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  • richardmitnick 5:17 pm on November 20, 2018 Permalink | Reply
    Tags: , , , , , ESO HARPS, HD186302-possible twin sibling to our Sung   

    From Instituto de Astrofísica e Ciências do Espaço via Science Alert: “Astronomers May Have Just Discovered Our Sun’s Long-Lost Identical Twin” 

    Instituto de Astrofísica e Ciências do Espaço

    via

    Science Alert

    20 NOV 2018
    MICHELLE STARR

    An international team [1], led by Instituto de Astrofísica e Ciências do Espaço (IA [2]) researcher Vardan Adibekyan, used a novel method to detect solar siblings. The article [3] was published in the journal Astronomy & Astrophysics.

    Solar siblings are the thousands of stars which formed in the same massive cluster as the Sun, about 4.6 billion years ago. As time went by, the stars in the cluster disbanded and scattered throughout our galaxy, making it very difficult to find them.

    Vardan Adibekyan (IA & University of Porto) explains the importance of finding these stars: “Since there isn’t much information about the Sun’s past, studying these stars can help us understand where in the Galaxy and under which conditions the Sun was formed.”

    He adds: “With the collaboration of Patrick de Laverny and Alejandra Recio-Blanco, from the Côte d’Azur observatory, we got a sample of 230 000 spectra from the AMBRE project.”

    Côte d’Azur Observatory, Nice, France Lunar Laser Ranging

    Côte d’Azur Observatory, Nice France

    AMBRE is a galactic archaeology project set up by ESO and the Observatoire de la Côte d’Azur, in order to determine the stellar atmospheric parameters for the archived spectra from ESO’s FEROS, HARPS [4], UVES and GIRAFFE spectrographs.

    ESO FEROS, a state-of-the-art bench-mounted, high-resolution, environmentally controlled, astronomical Échelle spectrograph. It is opertated at the European Southern Observatory (ESO) in La Silla, Chile

    UVES spectrograph mounted on the VLT at the Nasmyth B focus of UT2

    GIRAFFE on the VLT for intermediate and high resolution spectroscopy of galactic and extragalactic objects having a high spatial density used especially with FLAMES

    ESO/FLAMES on The VLT. FLAMES is the multi-object, intermediate and high resolution spectrograph of the VLT. Mounted at UT2, KUEYEN, FLAMES can access targets over a field of view 25 arcmin in diameter. FLAMES feeds two different spectrograph covering the whole visual spectral range:GIRAFFE and UVES.

    Next, the team used these very high quality spectral data from the AMBRE project together with very precise astrometric data retrieved from the second release of ESA’s GAIA mission, in order to: “make a selection of stars with chemical compositions which best match the Sun’s composition, followed by an estimate of these stars age and kinematic properties”, said Vardan Adibekyan.

    ESA/GAIA satellite

    ESA GAIA Release 2 map

    Although only a single solar sibling was found in this work – HD186302, it was a special one. This G3 type main sequence star is not only a solar sibling by both age and chemical composition, but it is also a solar twin.

    Solar siblings might also be good candidates to search for life since there is a possibility that life could have been transported between planets around stars of the solar cluster. The transfer of life between exoplanetary systems is called interstellar lithopanspermia.

    Adibekyan is cautiously excited about this possibility: “Some theoretical calculations show that there is non-negligible probability that life spread from Earth to other planets or exoplanetary systems, during the period of the late heavy bombardment. If we are lucky, and our sibling candidate has a planet, and the planet is a rocky type, in the habitable zone, and finally if this planet was ‘contaminated’ by the life seeds from Earth, then we have what one could dream – an Earth 2.0, orbiting a Sun 2.0.”

    The team at IA plans to start a campaign to search for planets around this star using both HARPS and ESPRESSO spectrographs [5]. Finding and characterizing planetary systems around solar siblings could return very important information about the outcome of planet formation in a common environment.

    Notes

    1.The team is Vardan Adibekyan, Sérgio Sousa, Elisa Delgado-Mena, Andressa Ferreira, Maria Tsantaki (Instituto de Astrofísica e Ciências do Espaço), Nuno Cardoso Santos (Instituto de Astrofísica e Ciências do Espaço and Faculdade de Ciências da Universidade do Porto), Patrick de Laverny, Alejandra Recio–Blanco, Georges Kordopatis (Observatoire de la Côte d’Azur), Ashot Hakobyan (Byurakan Astrophysical Observatory).

    2.The Instituto de Astrofísica e Ciências do Espaço (Institute of Astrophysics and Space Sciences – IA) is the largest Portuguese research unit of space sciences, which integrates researchers from University of Porto and University of Lisbon, and encompasses most of the field’s national scientific output. It was evaluated as Excellent in the last evaluation from the European Science Foundation (ESF). IA’s activity is funded by national and international funds, including Fundação para a Ciência e a Tecnologia (UID/FIS/04434/2013), POPH/FSE and FEDER through COMPETE 2020.

    3.The article “The AMBRE project: searching for the closest solar siblings” was published in the journal Astronomy & Astrophysics [link is above], Vol. 619, November 2018 (DOI: 10.1051/0004-6361/201834285).
    4.HARPS (High Accuracy Radial velocity Planet Searcher) is a high resolution spectrograph, installed at ESO’s 3.6 meter telescope in La Silla Observatory (Chile). It can detect variations in velocity smaller than 4 km/h (or roughly the speed of a person walking).

    ESO/HARPS at La Silla

    ESO 3.6m telescope & HARPS at LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    5.ESPRESSO (Echelle SPectrogaph for Rocky Exoplanet and Stable Spectroscopic Observations) is a high resolution spectrograph, installed at ESO’s Very Large Telescope (VLT). It has been designed with the goal of searching and detecting Earth-like planets, capable of supporting life. To do so, it can measure variations in velocity as low as 0.3 km/h. It also aims to test the stability of the fundamental constants of the Universe. The consortium that developed and built ESPRESSO gathers academic and scientific institutions from Portugal, Italy, Switzerland and Spain, as well as the European Southern Observatory (ESO). In Portugal, the effort was led by IA (University of Porto and University of Lisbon) and Faculdade de Ciências da Universidade de Lisboa (FCUL).

    ESO/ESPRESSO on the VLT,installed at the incoherent combined Coudé facility of the VLT. It is an ultra-stable fibre-fed échelle high-resolution spectrograph (R~140,000, 190,000, or 70,000) which collects the light from either a single UT or the four UTs simultaneously via the so-called UT Coudé trains

     
    • Artur Hakobyan 5:11 am on November 21, 2018 Permalink | Reply

      In the post please correct the name “Ashot Hakobyan”, must be “Artur Hakobyan”, thank you in advance.

      Like

      • richardmitnick 2:02 pm on November 21, 2018 Permalink | Reply

        You will have to contact the writer of the article for any connections. There is a link to the article for your use,

        Like

  • richardmitnick 7:24 am on November 15, 2017 Permalink | Reply
    Tags: , , , , ESO HARPS,   

    From ESO: “Closest Temperate World Orbiting Quiet Star Discovered” 

    ESO 50 Large

    European Southern Observatory

    15 November 2017
    Xavier Bonfils
    Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS
    Grenoble, France
    xavier.bonfils@univ-grenoble-alpes.fr

    Nicola Astudillo-Defru
    Geneva Observatory – University of Geneva
    Geneva, Switzerland
    nicola.astudillo@unige.ch

    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    rhook@eso.org

    1
    A temperate Earth-sized planet has been discovered only 11 light-years from the Solar System by a team using ESO’s unique planet-hunting HARPS instrument. The new world has the designation Ross 128 b and is now the second-closest temperate planet to be detected after Proxima b. It is also the closest planet to be discovered orbiting an inactive red dwarf star, which may increase the likelihood that this planet could potentially sustain life. Ross 128 b will be a prime target for ESO’s Extremely Large Telescope, which will be able to search for biomarkers in the planet’s atmosphere.

    A team working with ESO’s High Accuracy Radial velocity Planet Searcher (HARPS) at the La Silla Observatory in Chile has found that the red dwarf star Ross 128 is orbited by a low-mass exoplanet every 9.9 days. This Earth-sized world is expected to be temperate, with a surface temperature that may also be close to that of the Earth. Ross 128 is the “quietest” nearby star to host such a temperate exoplanet.

    ESO/HARPS at La Silla

    ESO 3.6m telescope & HARPS at Cerro LaSilla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    “This discovery is based on more than a decade of HARPS intensive monitoring together with state-of-the-art data reduction and analysis techniques. Only HARPS has demonstrated such a precision and it remains the best planet hunter of its kind, 15 years after it began operations,” explains Nicola Astudillo-Defru (Geneva Observatory – University of Geneva, Switzerland), who co-authored the discovery paper.

    Red dwarfs are some of the coolest, faintest — and most common — stars in the Universe. This makes them very good targets in the search for exoplanets and so they are increasingly being studied. In fact, lead author Xavier Bonfils (Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS, Grenoble, France), named their HARPS programme The shortcut to happiness, as it is easier to detect small cool siblings of Earth around these stars, than around stars more similar to the Sun [1].

    Many red dwarf stars, including Proxima Centauri, are subject to flares that occasionally bathe their orbiting planets in deadly ultraviolet and X-ray radiation.

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    However, it seems that Ross 128 is a much quieter star, and so its planets may be the closest known comfortable abode for possible life.

    2

    Although it is currently 11 light-years from Earth, Ross 128 is moving towards us and is expected to become our nearest stellar neighbour in just 79 000 years — a blink of the eye in cosmic terms. Ross 128 b will by then take the crown from Proxima b and become the closest exoplanet to Earth!

    With the data from HARPS, the team found that Ross 128 b orbits 20 times closer than the Earth orbits the Sun. Despite this proximity, Ross 128 b receives only 1.38 times more irradiation than the Earth. As a result, Ross 128 b’s equilibrium temperature is estimated to lie between -60 and 20°C, thanks to the cool and faint nature of its small red dwarf host star, which has just over half the surface temperature of the Sun. While the scientists involved in this discovery consider Ross 128b to be a temperate planet, uncertainty remains as to whether the planet lies inside, outside, or on the cusp of the habitable zone, where liquid water may exist on a planet’s surface [2].

    Astronomers are now detecting more and more temperate exoplanets, and the next stage will be to study their atmospheres, composition and chemistry in more detail. Vitally, the detection of biomarkers such as oxygen in the very closest exoplanet atmospheres will be a huge next step, which ESO’s Extremely Large Telescope (ELT) is in prime position to take [3].

    “New facilities at ESO will first play a critical role in building the census of Earth-mass planets amenable to characterisation. In particular, NIRPS, the infrared arm of HARPS, will boost our efficiency in observing red dwarfs, which emit most of their radiation in the infrared. And then, the ELT will provide the opportunity to observe and characterise a large fraction of these planets,” concludes Xavier Bonfils.
    Notes

    [1] A planet orbiting close to a low-mass red dwarf star has a larger gravitational effect on the star than a similar planet orbiting further out from a more massive star like the Sun. As a result, this “reflex motion” velocity is much easier to spot. However, the fact that red dwarfs are fainter makes it harder to collect enough signal for the very precise measurements that are needed.

    [2] The habitable zone is defined by the range of orbits around a star in which a planet can possess the appropriate temperature for liquid water to exist on the planet’s surface.

    [3] This is only possible for the very few exoplanets that are close enough to the Earth to be angularly resolved from their stars.
    More information

    This research was presented in a paper entitled “A temperate exo-Earth around a quiet M dwarf at 3.4 parsecs”, by X. Bonfils et al., to appear in the journal Astronomy & Astrophysics.

    The team is composed of X. Bonfils (Univ. Grenoble Alpes, CNRS, IPAG, Grenoble, France [IPAG]), N. Astudillo-Defru (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), R. Díaz (CONICET – Universidad de Buenos Aires, Instituto de Astronomía y Física del Espacio (IAFE), Buenos Aires, Argentina), J.-M. Almenara (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), T. Forveille (IPAG), F. Bouchy (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), X. Delfosse (IPAG), C. Lovis (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), M. Mayor (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), F. Murgas (Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain), F. Pepe (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), N. C. Santos (Instituto de Astrofísica e Ciências do Espaço and Universidade do Porto, Portugal), D. Ségransan (Observatoire de Genève, Université de Genève, Sauverny, Switzerland), S. Udry (Observatoire de Genève, Université de Genève, Sauverny, Switzerland) and A. Wü̈nsche (IPAG)

    See the full article here .

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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT
    VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level.

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level.

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres.

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m.

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert.

    Leiden MASCARA instrument, La Silla, located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    Leiden MASCARA cabinet at ESO Cerro la Silla located in the southern Atacama Desert 600 kilometres (370 mi) north of Santiago de Chile at an altitude of 2,400 metres (7,900 ft)

    ESO Next Generation Transit Survey at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    SPECULOOS four 1m-diameter robotic telescopes 2016 in the ESO Paranal Observatory, 2,635 metres (8,645 ft) above sea level

    ESO TAROT telescope at Paranal, 2,635 metres (8,645 ft) above sea level

     
  • richardmitnick 10:34 am on November 8, 2017 Permalink | Reply
    Tags: , , , , ESO HARPS, ,   

    From Red Dots: “Full HARPS 2017 dataset now available” 

    Red Dots

    7th November 2017
    Guillem Anglada-Escude

    1
    We have been a bit busy organizing the data, but the final HARPS dataset from Red Dots is now available for downloads at

    https://spasrv09.ph.qmul.ac.uk/owncloud/index.php/s/6CChGuyxNjPQRnP

    If you want make use of the data for scientific publications, remember that this is still preliminary, and that we welcome contributions and open discussions on this dataset. We mentioned the possibility of a second strong signal in Proxima’s RVs. Instead of forcing our conclusions into you, we let you take a look at all the observations and try to draw your initial conclusions (if you are new, we suggest using the systemic tool) For those with technical expertise in high resolution spectroscopy and science formats, you can access the ESO reduced files in the Proxima/Spectra folder, and the corresponding up-to-date radial velocities in Proxima/timeseries/.

    2
    Periodogram search on the ‘Red Dots 2017’ data set only. As in last year, the signal at ~11 days is significant in the new set, adding further robustness to the detection of Proxima b. This also implies we are likely to reach similar sensitivities on the other two stars (Barnard’s and Ross 154). Exciting. Combination with previous data might reveal additional signals, but these analyses will take more time and thinking. Image credits : Guillem Anglada/Red Dots

    A very quick analyses of the 2017 only data, shows that the signal of Proxima b is again detected with the new data set only! This was not the case for a while (data from first weeks was not as good as last year), but it looks like that in the end Proxima b’s signal remains in healthy confirmed state.

    3
    The spectrum taken on Sep 24th and a few other nights was not usable due to contamination by Sun-light. This typically happens due to twilight observation, moon proximity and/or the presence of high clouds scattering light. Red is the spectra registered on Sep 24th, and black is data registered in a good night with dark conditions. Image credits : Guillem Anglada-Escude/Red Dots

    It is worth mentioning that we dropped three spectra because they were badly contaminated with solar-like stray-light. That happens because they were taken a bit too early after the sunset, because the moon was near the star on the sky, presence of high clouds scattering sun & moonlight, or a combination of the three. These spectra are in Proxima/Spectra/contaminated/ in case anyone has a use for them.

    The photometric datasets are almost ready, but we need to clean them up and organize a little. Data is coming from more than a dozen observatories and the formats are not fully consistent with each other. Lot’s of spreadsheet work to do!

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Red dots is a project to attempt detection of the nearest terrestrial planets to the Sun. Terrestrial planets in temperate orbits around nearby red dwarf stars can be more easily detected using Doppler spectroscopy, hence the name of the project.

    ESO 3.6m telescope & HARPS at LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO/HARPS at La Silla

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

     
  • richardmitnick 2:49 pm on July 14, 2017 Permalink | Reply
    Tags: , , , Centauri System, , ESO HARPS,   

    From Red Dots: “Proxima Centauri HARPS data release #1” 

    Red Dots

    14th July 2017
    Guillem Anglada-Escude

    The first spectra obtained by HARPS are now publicly available at https://reddots.space/data/

    1
    New radial velocity measurements obtained since June 1st 2017 using HARPS. As in the other plot, the blue line is the best fit to a two sinusoid solution. Looks like the signal of Proxima b is holding well (phew!), but more data will be needed to figure out the nature of the second signal.

    We planned earlier releases, but weather conditions were not great. So far, we have collected 10 out of 22 possible epochs, which is not a great success rate. The data is organised as follows

    Proxima/timeseries

    Proxima/spectra

    In ‘Proxima/timeseries’, you will find the latest radial velocity measurements and the ‘historical’ data sets used in last year’s paper. They are provided as ‘night’ averages for simplicity. If you have never worked with time-series before, software packages such as Systemic should make your life easier. Check the community tools available here https://reddots.space/toolkit/

    The files are regular text (ASCII files) and can be imported to analysis and plotting tools such as Excel, LibreOffice, gnuplot, etc.

    The new data is showing interesting features when combined with previous ones. To avoid biasing you and our colleagues, we will refrain ourselves from commenting for now!

    3
    Radial velocities from Proxima Centauri as obtained by HARPS on 2016 (Pale Red Dot campaign). The blue line is the best fit model to two signals; Proxima b’s one and some longer term variability of (yet) unclear origin.

    If you have opinions and/or things you would like to discuss about the time-series and the spectra, please do so in the comments to this post, or via social media (including the @RedDotsSpace (Facebook and/or Twitter) or hashtag #reddots. Photometry and comments on the other stars to follow soon!

    4
    New radial velocity measurements obtained since June 1st 2017 using HARPS. As in the other plot, the blue line is the best fit to a two sinusoid solution. Looks like the signal of Proxima b is holding well (phew!), but more data will be needed to figure out the nature of the second signal.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Red dots is a project to attempt detection of the nearest terrestrial planets to the Sun. Terrestrial planets in temperate orbits around nearby red dwarf stars can be more easily detected using Doppler spectroscopy, hence the name of the project.

    ESO 3.6m telescope & HARPS at LaSilla, 600 km north of Santiago de Chile at an altitude of 2400 metres.

    ESO/HARPS at La Silla

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

     
  • richardmitnick 10:02 pm on May 26, 2017 Permalink | Reply
    Tags: , , , , , ESO HARPS, LHS 1140, MEarth-South telescope array at Cerro Tololo Inter-American Observatory,   

    From CfA: “Potentially Habitable Super-Earth is a Prime Target for Atmospheric Study” 

    Harvard Smithsonian Center for Astrophysics


    Center For Astrophysics

    April 19, 2017
    Megan Watzke
    Harvard-Smithsonian Center for Astrophysics
    +1 617-496-7998
    mwatzke@cfa.harvard.edu

    Peter Edmonds
    Harvard-Smithsonian Center for Astrophysics
    +1 617-571-7279
    pedmonds@cfa.harvard.edu

    1
    M. Weiss/CfA

    The study of alien worlds is entering its next phase as astronomers amass the best planets outside our Solar System to look for signs of life. A newly discovered “super-Earth” orbiting in the habitable zone of a nearby small star, has catapulted itself to the top of that list.

    “This is the most exciting exoplanet I’ve seen in the past decade,” said lead author Jason Dittmann of the Harvard-Smithsonian Center for Astrophysics (CfA). “We could hardly hope for a better target to perform one of the biggest quests in science − searching for evidence of life beyond Earth.”

    The newfound planet is described in a paper appearing in the April 20th issue of the journal Nature.

    Located just 40 light-years away, the planet was found using the transit method, in which a star dims as a planet crosses in front of it as seen from Earth.

    Planet transit. NASA/Ames

    By measuring how much light this planet blocks, the team determined that it is about 11,000 miles in diameter, or about 40 percent larger than Earth.

    The researchers have also weighed the planet to be 6.6 times the mass of Earth, showing that it is dense and likely has a rocky composition. Small, potentially habitable planets have been found in the TRAPPIST-1 system, located a similar distance from Earth, but only one of those worlds has had its density measured accurately, showing that it isn’t rocky. Therefore, some or all of the others also might not be rocky.

    Since this planet transits its star, unlike the closest world to the solar system Proxima Centauri b, it can be examined for the presence of air. As the planet moves in front of the star, the star’s light will be filtered through any atmosphere and leave an imprint. Large, next-generation telescopes will be needed to tease out these subtle signals.

    “This planet will be an excellent target for the James Webb Space Telescope when it launches in 2018, and I’m especially excited about studying it with the ground-based Giant Magellan Telescope, which is under construction,” said co-author David Charbonneau of the CfA.

    NASA/ESA/CSA Webb Telescope annotated

    Giant Magellan Telescope, to be at Las Campanas Observatory, to be built some 115 km (71 mi) north-northeast of La Serena, Chile

    The planet orbits a tiny, faint star known as LHS 1140, which is only one-fifth the size of the Sun. Since the star is so dim and cool, its habitable zone (the distance at which a planet might be warm enough to hold liquid water) is very close. This planet, designated LHS 1140 b, orbits its star every 25 days. At that distance, it receives about half as much sunlight from its star as Earth.

    Although the planet is potentially habitable now, it might have faced a hellish past. When the star was young, it would have bathed the planet in a harsh ultraviolet glare that could have stripped any water from the atmosphere, leading to a runaway greenhouse effect like we see on Venus.

    However, since the planet is larger than Earth, it might have possessed a magma ocean on its surface for millions of years. Powered by heat from naturally radioactive elements, that churning ocean of lava may have fed steam into the atmosphere long after the star calmed to its current, steady glow. This process could have replenished the planet with water, making it suitable for life as we know it.

    “Right now we’re just making educated guesses about the content of this planet’s atmosphere,” said Dittmann. “Future observations might enable us to detect the atmosphere of a potentially habitable planet for the first time. We plan to search for water, and ultimately molecular oxygen.”

    In contrast with the TRAPPIST-1 star, LHS 1140 spins slowly and does not emit much high-energy radiation, which also may help the likelihood of life on its planet.

    LHS 1140 b was discovered using the MEarth-South telescope array at Cerro Tololo Inter-American Observatory.

    2
    MEarth-South telescope array at Cerro Tololo Inter-American Observatory

    This collection of eight telescopes, with its companion facility MEarth-North, studies faint, red stars known as M dwarfs to locate orbiting planets using the transit method.

    In follow-up work the team was able to detect LHS 1140 wobbling as the planet orbits it, using the High Accuracy Radial velocity Planet Searcher (HARPS) installed on the European Southern Observatory’s 3.6m telescope at La Silla Observatory in Chile.

    ESO/HARPS at La Silla


    ESO 3.6m telescope & HARPS at LaSilla

    This information was combined with data from the transit method, allowing the team to make good measurements of the planet’s size, mass and density.

    The MEarth Project is supported by the National Science Foundation, the David and Lucile Packard Foundation, and the John Templeton Foundation.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

     
  • richardmitnick 12:54 pm on April 19, 2017 Permalink | Reply
    Tags: , , , , , ESO HARPS, , MEarth North AZ USA, Red dwarfs   

    From ESO: “Newly Discovered Exoplanet May be Best Candidate in Search for Signs of Life” 

    ESO 50 Large

    European Southern Observatory

    19 April 2017
    Jason Dittmann
    Harvard-Smithsonian Center for Astrophysics
    Cambridge, USA
    Email: jdittmann@cfa.harvard.edu

    Nicola Astudillo-Defru
    Geneva Observatory – Université of Geneva
    Geneva, Switzerland
    Email: nicola.astudillo@unige.ch

    Xavier Bonfils
    Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS
    Grenoble, France
    Email: xavier.bonfils@univ-grenoble-alpes.fr

    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Megan Watzke
    Harvard-Smithsonian Center for Astrophysics
    Cambridge, USA
    Tel: +1 617-496-7998
    Email: mwatzke@cfa.harvard.edu

    1
    An exoplanet orbiting a red dwarf star 40 light-years from Earth may be the new holder of the title “best place to look for signs of life beyond the Solar System”. Using ESO’s HARPS instrument at La Silla, and other telescopes around the world, an international team of astronomers discovered a “super-Earth” orbiting in the habitable zone around the faint star LHS 1140.

    ESO/HARPS at La Silla

    ESO 3.6m telescope & HARPS at LaSilla

    This world is a little larger and much more massive than the Earth and has likely retained most of its atmosphere. This, along with the fact that it passes in front of its parent stars as it orbits, makes it one of the most exciting future targets for atmospheric studies. The results will appear in the 20 April 2017 issue of the journal Nature.

    The newly discovered super-Earth LHS 1140b orbits in the habitable zone around a faint red dwarf star, named LHS 1140, in the constellation of Cetus (The Sea Monster) [1]. Red dwarfs are much smaller and cooler than the Sun and, although LHS 1140b is ten times closer to its star than the Earth is to the Sun, it only receives about half as much sunlight from its star as the Earth and lies in the middle of the habitable zone. The orbit is seen almost edge-on from Earth and as the exoplanet passes in front of the star once per orbit it blocks a little of its light every 25 days.

    “This is the most exciting exoplanet I’ve seen in the past decade,” said lead author Jason Dittmann of the Harvard-Smithsonian Center for Astrophysics (Cambridge, USA). “We could hardly hope for a better target to perform one of the biggest quests in science — searching for evidence of life beyond Earth.”

    “The present conditions of the red dwarf are particularly favourable — LHS 1140 spins more slowly and emits less high-energy radiation than other similar low-mass stars,” explains team member Nicola Astudillo-Defru from Geneva Observatory, Switzerland [2].

    For life as we know it to exist, a planet must have liquid surface water and retain an atmosphere. When red dwarf stars are young, they are known to emit radiation that can be damaging for the atmospheres of the planets that orbit them. In this case, the planet’s large size means that a magma ocean could have existed on its surface for millions of years. This seething ocean of lava could feed steam into the atmosphere long after the star has calmed to its current, steady glow, replenishing the planet with water.

    The discovery was initially made with the MEarth facility, which detected the first telltale, characteristic dips in light as the exoplanet passed in front of the star. ESO’s HARPS instrument, the High Accuracy Radial velocity Planet Searcher, then made crucial follow-up observations which confirmed the presence of the super-Earth. HARPS also helped pin down the orbital period and allowed the exoplanet’s mass and density to be deduced [3].

    2
    On a dramatic ridge in the Coronado National Forest, the MEarth-North observatory is housed in single enclosure with a roll-off roof on Mount Hopkins, AZ, USA

    The astronomers estimate the age of the planet to be at least five billion years. They also deduced that it has a diameter 1.4 times larger than the Earth — almost 18 000 kilometres. But with a mass around seven times greater than the Earth, and hence a much higher density, it implies that the exoplanet is probably made of rock with a dense iron core.

    This super-Earth may be the best candidate yet for future observations to study and characterise its atmosphere, if one exists. Two of the European members of the team, Xavier Delfosse and Xavier Bonfils both at the CNRS and IPAG in Grenoble, France, conclude: “The LHS 1140 system might prove to be an even more important target for the future characterisation of planets in the habitable zone than Proxima b or TRAPPIST-1. This has been a remarkable year for exoplanet discoveries!” [4,5].

    In particular, observations coming up soon with the NASA/ESA Hubble Space Telescope will be able to assess exactly how much high-energy radiation is showered upon LHS 1140b, so that its capacity to support life can be further constrained.

    Further into the future — when new telescopes like ESO’s Extremely Large Telescope are operating — it is likely that we will be able to make detailed observations of the atmospheres of exoplanets, and LHS 1140b is an exceptional candidate for such studies.

    Notes

    [1] The habitable zone is defined by the range of orbits around a star, for which a planet possesses the appropriate temperature needed for liquid water to exist on the planet’s surface.

    [2] Although the planet is located in the zone in which life as we know it could potentially exist, it probably did not enter this region until approximately forty million years after the formation of the red dwarf star. During this phase, the exoplanet would have been subjected to the active and volatile past of its host star. A young red dwarf can easily strip away the water from the atmosphere of a planet forming within its vicinity, leading to a runaway greenhouse effect similar to that on Venus.

    [3] This effort enabled other transit events to be detected by MEarth so that the astronomers could nail down the detection of the exoplanet once and for all.

    [4] The planet around Proxima Centauri (eso1629) is much closer to Earth, but it probably does not transit its star, making it very difficult to determine whether it holds an atmosphere.

    [5] Unlike the TRAPPIST-1 system (eso1706), no other exoplanets around LHS 1140 have been found. Multi-planet systems are thought to be common around red dwarfs, so it is possible that additional exoplanets have gone undetected so far because they are too small.

    More information

    This research was presented in a paper entitled A temperate rocky super-Earth transiting a nearby cool star, by J. A. Dittmann et al. to appear in the journal Nature [link is above in image caption] on 20 April 2017.

    The team is composed of Jason A. Dittmann (Harvard Smithsonian Center for Astrophysics, USA), Jonathan M. Irwin (Harvard Smithsonian Center for Astrophysics, USA), David Charbonneau (Harvard Smithsonian Center for Astrophysics, USA), Xavier Bonfils (Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS, France), Nicola Astudillo-Defru (Observatoire de Genève, Switzerland), Raphaëlle D. Haywood (Harvard Smithsonian Center for Astrophysics, USA), Zachory K. Berta-Thompson (University of Colorado, USA), Elisabeth R. Newton (MIT, USA), Joseph E. Rodriguez (Harvard Smithsonian Center for Astrophysics, USA), Jennifer G. Winters (Harvard Smithsonian Center for Astrophysics, USA), Thiam-Guan Tan (Perth Exoplanet Survey Telescope, Australia), José-Manuel Almenara (Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS, France; Observatoire de Genève, Switzerland), François Bouchy (Aix Marseille Université, France), Xavier Delfosse (Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes / CNRS, France), Thierry Forveille (Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes/CNRS, France), Christophe Lovis (Observatoire de Genève, Switzerland), Felipe Murgas (Institut de Planétologie et d’Astrophysique de Grenoble – Université Grenoble-Alpes / CNRS, France; IAC, Spain), Francesco Pepe (Observatoire de Genève, Switzerland), Nuno C. Santos (Instituto de Astrofísica e Ciências do Espaço and Universidade do Porto, Portugal), Stephane Udry (Observatoire de Genève, Switzerland), Anaël Wünsche (CNRS/IPAG, France), Gilbert A. Esquerdo (Harvard Smithsonian Center for Astrophysics, USA), David W. Latham (Harvard Smithsonian Center for Astrophysics, USA) and Courtney D. Dressing (Caltech, USA).

    See the full article here .

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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres

    ESO VLT
    VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert

     
  • richardmitnick 10:24 am on March 27, 2017 Permalink | Reply
    Tags: , , , , ESO HARPS, , , IRAS F23128-5919, Stars Born in Winds from Supermassive Black Holes   

    From ESO: “Stars Born in Winds from Supermassive Black Holes” 

    ESO 50 Large

    European Southern Observatory

    27 March 2017
    Roberto Maiolino
    Cavendish Laboratory, Kavli Institute for Cosmology
    University of Cambridge, UK
    Email: r.maiolino@mrao.cam.ac.uk

    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    1
    Observations using ESO’s Very Large Telescope have revealed stars forming within powerful outflows of material blasted out from supermassive black holes at the cores of galaxies. These are the first confirmed observations of stars forming in this kind of extreme environment. The discovery has many consequences for understanding galaxy properties and evolution. The results are published in the journal Nature.

    A UK-led group of European astronomers used the MUSE and X-shooter instruments on the Very Large Telescope (VLT) at ESO’s Paranal Observatory in Chile to study an ongoing collision between two galaxies, known collectively as IRAS F23128-5919, that lie around 600 million light-years from Earth. The group observed the colossal winds of material — or outflows — that originate near the supermassive black hole at the heart of the pair’s southern galaxy, and have found the first clear evidence that stars are being born within them [1].

    2
    IRAS F23128-5919 https://inspirehep.net/record/1265769/plots


    ESO/MUSE on VLT


    ESO X-shooter on VLT

    Such galactic outflows are driven by the huge energy output from the active and turbulent centres of galaxies. Supermassive black holes lurk in the cores of most galaxies, and when they gobble up matter they also heat the surrounding gas and expel it from the host galaxy in powerful, dense winds [2].

    “Astronomers have thought for a while that conditions within these outflows could be right for star formation, but no one has seen it actually happening as it’s a very difficult observation,” comments team leader Roberto Maiolino from the University of Cambridge. “Our results are exciting because they show unambiguously that stars are being created inside these outflows.”

    The group set out to study stars in the outflow directly, as well as the gas that surrounds them. By using two of the world-leading VLT spectroscopic instruments, MUSE and X-shooter, they could carry out a very detailed study of the properties of the emitted light to determine its source.

    Radiation from young stars is known to cause nearby gas clouds to glow in a particular way. The extreme sensitivity of X-shooter allowed the team to rule out other possible causes of this illumination, including gas shocks or the active nucleus of the galaxy.

    The group then made an unmistakable direct detection of an infant stellar population in the outflow [3]. These stars are thought to be less than a few tens of millions of years old, and preliminary analysis suggests that they are hotter and brighter than stars formed in less extreme environments such as the galactic disc.

    As further evidence, the astronomers also determined the motion and velocity of these stars. The light from most of the region’s stars indicates that they are travelling at very large velocities away from the galaxy centre — as would make sense for objects caught in a stream of fast-moving material.

    Co-author Helen Russell (Institute of Astronomy, Cambridge, UK) expands: “The stars that form in the wind close to the galaxy centre might slow down and even start heading back inwards, but the stars that form further out in the flow experience less deceleration and can even fly off out of the galaxy altogether.”

    The discovery provides new and exciting information that could better our understanding of some astrophysics, including how certain galaxies obtain their shapes [4]; how intergalactic space becomes enriched with heavy elements [5]; and even from where unexplained cosmic infrared background radiation may arise [6].

    Maiolino is excited for the future: “If star formation is really occurring in most galactic outflows, as some theories predict, then this would provide a completely new scenario for our understanding of galaxy evolution.”
    Notes

    [1] Stars are forming in the outflows at a very rapid rate; the astronomers say that stars totalling around 30 times the mass of the Sun are being created every year. This accounts for over a quarter of the total star formation in the entire merging galaxy system.

    [2] The expulsion of gas through galactic outflows leads to a gas-poor environment within the galaxy, which could be why some galaxies cease forming new stars as they age. Although these outflows are most likely to be driven by massive central black holes, it is also possible that the winds are powered by supernovae in a starburst nucleus undergoing vigorous star formation.

    [3] This was achieved through the detection of signatures characteristic of young stellar populations and with a velocity pattern consistent with that expected from stars formed at high velocity in the outflow.

    [4] Spiral galaxies have an obvious disc structure, with a distended bulge of stars in the centre and surrounded by a diffuse cloud of stars called a halo. Elliptical galaxies are composed mostly of these spheroidal components. Outflow stars that are ejected from the main disc could give rise to these galactic features.

    [5] How the space between galaxies — the intergalactic medium — becomes enriched with heavy elements is still an open issue, but outflow stars could provide an answer. If they are jettisoned out of the galaxy and then explode as supernovae, the heavy elements they contain could be released into this medium.

    [6] Cosmic-infrared background radiation, similar to the more famous cosmic microwave background, is a faint glow in the infrared part of the spectrum that appears to come from all directions in space. Its origin in the near-infrared bands, however, has never been satisfactorily ascertained. A population of outflow stars shot out into intergalactic space may contribute to this light.
    More information

    This research was presented in a paper entitled “Star formation in a galactic outflow” by Maiolino et al., to appear in the journal Nature on 27 March 2017 [link is above with image detail].

    The team is composed of R. Maiolino (Cavendish Laboratory; Kavli Institute for Cosmology, University of Cambridge, UK), H.R. Russell (Institute of Astronomy, Cambridge, UK), A.C. Fabian (Institute of Astronomy, Cambridge, UK), S. Carniani (Cavendish Laboratory; Kavli Institute for Cosmology, University of Cambridge, UK), R. Gallagher (Cavendish Laboratory; Kavli Institute for Cosmology, University of Cambridge, UK), S. Cazzoli (Departamento de Astrofisica-Centro de Astrobiología, Madrid, Spain), S. Arribas (Departamento de Astrofisica-Centro de Astrobiología, Madrid, Spain), F. Belfiore ((Cavendish Laboratory; Kavli Institute for Cosmology, University of Cambridge, UK), E. Bellocchi (Departamento de Astrofisica-Centro de Astrobiología, Madrid, Spain), L. Colina (Departamento de Astrofisica-Centro de Astrobiología, Madrid, Spain), G. Cresci (Osservatorio Astrofisico di Arcetri, Firenze, Italy), W. Ishibashi (Universität Zürich, Zürich, Switzerland), A. Marconi (Osservatorio Astrofisico di Arcetri, Firenze, Italy), F. Mannucci (Osservatorio Astrofisico di Arcetri, Firenze, Italy), E. Oliva (Osservatorio Astrofisico di Arcetri, Firenze, Italy), and E. Sturm (Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany).

    See the full article here .

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    ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

    ESO LaSilla
    ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres

    ESO VLT
    VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    ESO Vista Telescope
    ESO/Vista Telescope at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    ESO NTT
    ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres

    ESO VLT Survey telescope
    VLT Survey Telescope at Cerro Paranal with an elevation of 2,635 metres (8,645 ft) above sea level

    ALMA Array
    ALMA on the Chajnantor plateau at 5,000 metres

    ESO E-ELT
    ESO/E-ELT to be built at Cerro Armazones at 3,060 m

    ESO APEX
    APEX Atacama Pathfinder 5,100 meters above sea level, at the Llano de Chajnantor Observatory in the Atacama desert

     
  • richardmitnick 2:27 pm on August 25, 2016 Permalink | Reply
    Tags: , , ESO HARPS, , ,   

    From Don Lincoln via CNN: “A new planet in our neighborhood — how likely is life?” 

    1
    CNN

    August 24, 2016

    1
    Dr. Don Lincoln is a senior physicist at Fermilab and does research using the Large Hadron Collider. He has written numerous books and produces a series of science education videos. He is the author of Alien Universe: Extraterrestrial Life in Our Minds and in the Cosmos. Follow him on Facebook. The opinions expressed in this commentary are solely those of the author.

    Space. The final frontier.

    These words inspired many young people to enter science (including me), but I’ll bet that’s especially true for the team who announced Wednesday that they had found evidence of an Earth-like planet orbiting Proxima Centauri, our closest star. This planet is tentatively called Proxima b.

    Pale Red Dot
    Pale Red Dot project at ESO

    Scientists working at the European Southern Observatory (ESO), using the La Silla telescope, claim to have discovered the closest exoplanet to Earth.

    ESO 3.6m telescope & HARPS at LaSilla
    ESO 3.6m telescope & HARPS at LaSilla, Chile

    Exoplanet, of course, means planets orbiting stars other than the Sun. Over 3,000 exoplanets have been discovered by facilities like the ESO and the Kepler orbiting observatory. Most of them are huge planets orbiting very near their star — Jupiter-like planets heated to temperatures guaranteed to sterilize them of life as we know it.

    In recent years, instrumentation has improved to the point that not only can individual planets be found, but even complete solar systems, consisting of many planets. This has been a heady time for planet hunters.

    The goal of those inspired by Star Trek’s opening words has not been to find planets, but to find planets that are like Earth — meaning at a temperature on which liquid water could be present and which could theoretically support some form of life. This is what astronomers call “the habitable zone.” In addition, we’d like to find a planet that is nearby.

    After all, space is huge and human spacecraft using current technology would take tens of thousands of years to get to even this, our closest celestial neighbor. To give a sense of scale, that’s longer than human civilization has existed. There are plans under discussion that might reduce travel time to a more manageable duration, even less than a single human lifespan.

    3
    Related article: Proxima b: Closest rocky planet to our solar system found

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker
    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    So what might this newly discovered planet look like? Well, even though its temperature is thought to be such that liquid water could exist, you shouldn’t imagine a lush and verdant world, with lovely blue waters, sandy beaches, lush and green plants, with an excited alien fish occasionally breaching the waters. There are lots of reasons why these are unreasonable expectations.

    Setting aside the possibility of life for a moment, Proxima Centauri is a red dwarf, which is the most common type of star in the galaxy. Red dwarfs are much smaller than our Sun. For instance, Proxima Centauri is only about 1.5 times larger than Jupiter. Red dwarfs are very dim. For instance, in the visible spectrum that we use to see, Proxima Centauri gives off 0.0056% as much as light as the Sun.

    Most of the light given off by Proxima Centauri is in the infrared region, but even if you compare all of the light emitted by Proxima Centauri in all wavelengths to the amount emitted by the Sun, Proxima Centauri still emits only 0.17% as much light as our own life-giving stellar companion. The star also emits as much x-rays as our own Sun, but Proxima b is much closer to its stellar parent, so the surface receives far more x-rays than Earth.

    In addition to being a very dim star, Proxima Centauri is known to be a “flare star,” which means the star periodically gives off far more light than usual. During these flares, the x-ray emission can go up tenfold.

    Because of the star’s small size, a planet in the habitable zone will have to be in a very small orbit, taking under two weeks to complete a single orbit. Any planet that close to a star will be “tidally locked,” which means that one face of the planet will constantly face the star. This is just like the Earth and Moon, where we see only one side of the Moon throughout the course of the Month. Proxima Centauri’s planetary companion will likely have one side in perpetual daylight, while the other is in perpetual night.

    So what about life? Are there any chances that an alien lizard might bask in Proxima Centauri’s light or try to find shade under an alien tree? Well, given the instability of the light emitted by the parent star, the answer is likely no, although the real answer to that question is obviously something for observations to answer.

    Given the very dim light output of the star, it is likely that any hypothetical plants would have to be black, as black is the most light-absorbent color. “Sunlight” would be precious and evolution would drive alien plants to find ways to collect every bit of energy that falls on them.

    Realistically, the prospect of life is improbable. This planet is unlikely to be a haven for people trying to escape the ecological issues of Earth, so we should not view this discovery as a way to ignore our own ecosystem.

    Still, the question of extraterrestrial life is a fascinating one, so astronomers are devising techniques to look at the planet’s atmosphere. Certain chemicals, like oxygen or methane, cannot exist long in a planet’s atmosphere without being constantly replenished by living organisms. Observing them would be strong evidence for life.

    So, what’s the bottom line? First, the discovery, if confirmed is extremely exciting. The existence of a nearby planet in the habitable zone will perhaps increase the interest in efforts like Project Starshot, which aims to send microprobes to Proxima Centauri with a transit time of about twenty years. It may well be that this discovery will excite an entirely new generation of the prospect “to boldly go where no one has gone before.”

    See the full article here .

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  • richardmitnick 8:33 am on March 16, 2016 Permalink | Reply
    Tags: , , Bight spots on Ceres, ESO HARPS   

    From ESO: “Unexpected Changes of Bright Spots on Ceres Discovered” 

    ESO 50 Large

    European Southern Observatory

    16 March 2016
    Paolo Molaro
    INAF-Osservatorio Astronomico di Trieste
    Trieste, Italy
    Email: molaro@inaf.oats.it

    Richard Hook
    ESO Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    Ceres with bright spot ESO Harps
    Ceres with bright spot. ESO Harps

    Observations made using the HARPS spectrograph at ESO’s La Silla Observatory in Chile have revealed unexpected changes in the bright spots on the dwarf planet Ceres.

    ESO 3.6m telescope & HARPS at LaSilla
    Telescopio Nazionale Galileo - Harps North
    HARPS

    ESO LaSilla
    La Silla

    Although Ceres appears as little more than a point of light from the Earth, very careful study of its light shows not only the changes expected as Ceres rotates, but also that the spots brighten during the day and also show other variations. These observations suggest that the material of the spots is volatile and evaporates in the warm glow of sunlight.

    Ceres is the largest body in the asteroid belt between Mars and Jupiter and the only such object classed as a dwarf planet.

    Asteroid belt  Mdf
    Asteroid belt. Mdf

    NASA’s Dawn spacecraft has been in orbit around Ceres for more than a year and has mapped its surface in great detail.

    NASA Dawn Spacescraft
    NASA/Dawn

    One of the biggest surprises has been the discovery of very bright spots, which reflect far more light than their much darker surroundings [1]. The most prominent of these spots lie inside the crater Occator and suggest that Ceres may be a much more active world than most of its asteroid neighbours.

    New and very precise observations using the HARPS spectrograph at the ESO 3.6-metre telescope at La Silla, Chile, have now not only detected the motion of the spots due to the rotation of Ceres about its axis, but also found unexpected additional variations suggesting that the material of the spots is volatile and evaporates in sunlight.

    ESO 3.6m telescope & HARPS at LaSilla
    ESO 3.6 meter telescope interior
    ESO 3.6 meter telescope at La Silla

    The lead author of the new study, Paolo Molaro, at the INAF–Trieste Astronomical Observatory, takes up the story: “As soon as the Dawn spacecraft revealed the mysterious bright spots on the surface of Ceres, I immediately thought of the possible measurable effects from Earth. As Ceres rotates the spots approach the Earth and then recede again, which affects the spectrum of the reflected sunlight arriving at Earth.”

    Ceres spins every nine hours and calculations showed that the effects due to the motion of the spots towards and away from the Earth caused by this rotation would be very small, of order 20 kilometres per hour. But this motion is big enough to be measurable via the Doppler effect with high-precision instruments such as HARPS.

    The team observed Ceres with HARPS for a little over two nights in July and August 2015. “The result was a surprise,” adds Antonino Lanza, at the INAF–Catania Astrophysical Observatory and co-author of the study. “We did find the expected changes to the spectrum from the rotation of Ceres, but with considerable other variations from night to night.”

    The team concluded that the observed changes could be due to the presence of volatile substances that evaporate under the action of solar radiation [2]. When the spots inside the Occator crater are on the side illuminated by the Sun they form plumes that reflect sunlight very effectively. These plumes then evaporate quickly, lose reflectivity and produce the observed changes. This effect, however, changes from night to night, giving rise to additional random patterns, on both short and longer timescales.

    If this interpretation is confirmed Ceres would seem to be very different from Vesta and the other main belt asteroids. Despite being relatively isolated, it seems to be internally active [3]. Ceres is known to be rich in water, but it is unclear whether this is related to the bright spots. The energy source that drives this continual leakage of material from the surface is also unknown.

    Dawn is continuing to study Ceres and the behaviour of its mysterious spots. Observations from the ground with HARPS and other facilities will be able to continue even after the end of the space mission.
    Notes

    [1] Bright spots were also seen, with much less clarity, in earlier images of Ceres from the NASA/ESA Hubble Space Telescope taken in 2003 and 2004.

    NASA Hubble Telescope
    NASA/ESA Hubble

    [2] It has been suggested that the highly reflective material in the spots on Ceres might be freshly exposed water ice or hydrated magnesium sulphates.

    [3] Many of the most internally active bodies in the Solar System, such as the large satellites of Jupiter and Saturn, are subjected to strong tidal effects due to their proximity to the massive planets.

    More information

    This research was presented in a paper entitled Daily variability of Ceres’ Albedo detected by means of radial velocities changes of the reflected sunlight, by P. Molaro et al., which appeared in the journal Monthly Notices of the Royal Astronomical Society.

    The team is composed of P. Molaro (INAF-Osservatorio Astronomico di Trieste, Trieste, Italy), A. F. Lanza (INAF-Osservatorio Astrofisico di Catania, Catania, Italy), L. Monaco (Universidad Andres Bello, Santiago, Chile), F. Tosi (INAF-IAPS Istituto di Astrofisica e Planetologia Spaziali, Rome, Italy), G. Lo Curto (ESO, Garching, Germany), M. Fulle (INAF-Osservatorio Astronomico di Trieste, Trieste, Italy) and L. Pasquini (ESO, Garching, Germany).

    See the full article here .

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  • richardmitnick 2:12 pm on December 25, 2015 Permalink | Reply
    Tags: , , ESO HARPS, , Rocky Planet Found Around Star with Least Metal Yet,   

    From SPACE.com: “Rocky Planet Found Around Star with Least Metal Yet” 

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    SPACE.com

    December 25, 2015
    Jesse Emspak

    Temp 1
    Neptune-size planets like this one, drawn orbiting the star Gliese 436, may be able to form around stars that contain far less metal than previously thought. Credit: NASA

    How low can you go? Astronomers have found a star with an incredibly low concentration of heavy elements that still has a sizable planet around it — the most metal-poor star ever discovered with an orbiting, rocky planet.

    The planet found circling the unlikely star suggests that other Earths could be more common than once thought.

    A team led by Annelies Mortier, an exoplanet researcher at the University of St. Andrews in the United Kingdom, found the star, called HD175607, and its Neptune-size planet about 147 light-years from Earth, using the High Accuracy Radial Velocity Planet Searcher (HARPS) spectrograph in Chile.

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    The star is a yellowish dwarf, with about 0.74 times the mass of the sun, and it contains fewer heavy elements than any other star of its kind that has rocky planets. The ratio of iron to hydrogen, for example, is only 23 percent that of the sun’s.

    To make planets, you need elements heavier than hydrogen and helium. In astronomical parlance, these elements are known as metals, even though they include substances like oxygen, silicon and carbon. Astronomers can measure a star’s metallicity, or the ratio of heavy elements to hydrogen, by looking at the wavelengths of light coming from the star and comparing its metal content to the surrounding regions of the galaxy. The metallicity of a star also tells you what was likely in the cloud of gas and dust that formed it in the first place.

    Researchers generally expect stars with high metallicity to be more likely to have giant planets like Jupiter — in fact, astronomers target such stars in order to boost the odds of seeing a planet, Mortier told Space.com in an email. But for rocky, Neptune-size planets and those that are smaller, that correlation doesn’t appear to hold. That’s why the HARPS is looking at low-metallicity stars to see how low that ratio can go before the star no longer has planets at all.

    “For Neptunes and Earthlike planets, it is not as clear yet what the role of metallicity is,” Mortier said.

    In this case, the star HD175607 appears to have a planet orbiting it at a distance that’s about a third of Mercury’s to the sun. It completes a “year” of orbit in 29 days and weighs between 7.88 and 10.08 times as much as Earth, putting it at about two-thirds the mass of Neptune — which has a mass that’s about 17 times that of Earth’s.

    Planets are hard to see to begin with; finding the one around HD 175607 took months of observations spread out over nine years. The researchers had a much easier time measuring the star’s metallicity.

    Knowing what kinds of stars to target would go far toward helping observers discover other Earths — and a big question that remains is what kinds of planets are around what kinds of stars, Mortier said.

    Jarrett Johnson, a scientist at Los Alamos National Laboratory who has studied exoplanets and their relation to metallicity, told Space.com that this discovery of a rocky planet around a metal-poor star bodes well for finding more of them.

    “This is good news as it is evidence that lower and lower mass planets are being found around metal-poor stars, as more data is gathered with more powerful techniques [like HARPS],” he said.

    The discovery will also help refine models of planet formation. Currently, many scientists think that planets form when smaller objects group into bigger ones, which is called the core accretion model. In a 2012 study, Johnson worked out estimates of how much iron and other heavy elements had to be present to accrete planets, and new discoveries like this one could show whether those estimates are correct.

    The study was accepted for publication in the journal Astronomy & Astrophysics in November.

    See the full article here .

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