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  • richardmitnick 10:34 am on November 8, 2017 Permalink | Reply
    Tags: , , , , , , Red Dots campaign   

    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 5:25 pm on July 27, 2017 Permalink | Reply
    Tags: , , , , Red Dots campaign, Ross 154   

    From Red Dots: “The rapidly rotating Ross 154 – by Mikko Tuomi” 

    Red Dots

    27th July 2017
    Mikko Tuomi

    1
    Depiction of high energy emission from an active red dwarf. Credits: NASA’s Goddard Space Flight Center/S. Wiessinger. Source : https://www.nasa.gov/content/goddard/nasas-swift-mission-observes-mega-flares-from-a-mini-star.

    Perhaps the least known star in the Red Dots campaign, Ross 154, is a rapidly rotating M dwarf star that shows elevated activity levels and and flares on its surface. This makes the Red Dots campaign targets more diverse than they otherwise would be – rapid rotation is typically interpreted as a sign of young age of such stellar objects as the rotation period is thought to gradually increase due to magnetic friction resulting in old M dwarfs with slow rotation rates such as Proxima Centauri whose rotation period has been estimated to be 83 days [1]. Indeed, Ross 154 has been estimated to have an age of less than one billion years [2].

    The rotation of Ross 154 induces a clear photometric cycle of 2.87 days in our All Sky Automated Survey V-band observations but the brightness of the star also varies with another cycle of 740 days that we interpret to be caused by the star’s activity cycle (Fig. 1). Knowing these two “fundamental” cycles helps interpreting any and all periodicities in the radial velocity data because periodicities that are independent from both rotation and magnetic and/or activity cycles could correspond to planets orbiting the star.

    2
    Fig. 1. Likelihood-ratio periodogram of ASAS V-band photometry of Ross 154 showing evidence for a rotation period of 2.87 days and a magnetic activity cycle of 740 days.

    Due to its young age, Ross 154 is an active star and its radial velocities obtained by four independent spectrographs have elevated noise levels due to the star’s active surface. These high-precision spectrographs are HARPS (3.6m telescope, La Silla, Chile), HIRES (Keck telescope, Mauna Kea, Hawaii), PFS (Magellan 6.5m telescope, Las Campanas, Chile), and UCLES (Anglo-Australian Telescope, Siding Springs Observatory, Australia) but their precision is limited by stellar activity that induces radial velocity noise of some 10-20 m/s in the data, depending on the instrument.

    Keck Observatory, Maunakea, Hawaii, USA

    Keck HIRES

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile.

    2
    Magellan Planet Finder Spectrograph (PFS)

    AAO Anglo Australian Telescope near Siding Spring, New South Wales, Australia

    5
    AAT UCLES spectrograph

    4
    Fig. 2. Probability distribution as a function of signal period for Ross 154. The dominant maximum corresponds to a signal caused by the star’s rotation.

    5
    Fig. 3. Probability distribution as a function of the period of a second hypothetical signal for Ross 154. The emerging maxima are probably caused by stellar differential rotation and aliasing.

    Although reasonably noisy due to elevated activity in comparison to the typical radial velocity noise in M dwarf data of 2-4 m/s[3], Ross 154 appears to have a moderately significant periodicity in its velocity data set caused by the stellar rotation and the co-rotation of starspots on the stellar surface (Fig. 2).

    The Ross 154 radial velocities also show hints of additional periodic signals (Fig. 3), although they are not significantly present in the data. These are likely caused by aliasing and differential rotation of the star but the interpretation is difficult because there is not enough data to rule out alternative solutions present as local probability maxima in Figs. 2 and 3. The current data set is severely limited because the most precise HARPS data set contains only eight velocities. Red Dots campaign will increase this number roughly by a factor of ten, making it possible to search for signals of planets orbiting Ross 154.

    References [Sorry, no links provided.]

    Anglada-Escudé G. et al. “A Terrestrial Candidate in a Temperate Orbit Around Proxima Centauri”, Nature, 536, 437 (2016).
    Johns-Krull, C. M. & Valenti, J. A. “Detection of Strong Magnetic Fields on M Dwarfs”, The Astrophysical Journal, 459, L95 (1996).
    Butler R. P. et al. “The LCES HIRES/Keck Precision Radial Velocity Exoplanet Survey”, The Astronomical journal, 153, 208 (2017).

    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, , , Red Dots campaign   

    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 1:05 pm on June 23, 2017 Permalink | Reply
    Tags: , , , Red Dots campaign,   

    From Red Dot: “Is there life around the nearest stars? 

    Red Dots

    13th June 2017
    Avi Loeb

    1

    Is there extra-terrestrial life just outside the solar system? The recent discovery of Proxima b [1], a habitable Earth-mass planet next to the nearest star, opened a unique opportunity in the search for extra-terrestrial life.

    Centauris Alpha Beta Proxima 27, February 2012. Skatebiker

    It is much easier to study nearby habitats for life, either by remote sensing of the feeble radiation signals from biologically-produced molecules (e.g. oxygen) or by sending spacecrafts that will image the planet’s surface or collect samples from its atmosphere through a close encounter. The Breakthrough Starshot initiative, announced in April 2016 (and whose advisory committee I chair) aims to send lightweight (gram scale) probes to the nearest stars at a fifth of the speed of light, so as to inform us of nearby life-hosting environments within our generation. To properly select the Starshot targets, we would like to know which nearby stars host habitable planets like Proxima b. The treasure of data expected from the Red Dots campaign will be invaluable for guiding and motivating the Starshot project.

    2
    Artistic’s conception showing the Starshot project concept. A laser beam propels a light sail towards a nearby exoplanet such as Proxima b. The sail carries on its center a lightweight probe with several measuring instruments. Starshot will start soon the first five-year phase of technology demonstration at a funding level of $100M, provided by the entrepreneur and physicist Yuri Milner (Credit: Breakthrough Starshot).

    The chemistry of life as we know it requires liquid water, but being at the right distance from the host star for a comfortable temperature on the planet’s surface, is not a sufficient condition. The planet also needs to have an atmosphere. In the absence of an external atmospheric pressure, the warming of water ice transforms it into directly into gas phase rather than liquid. The warning sign is just next door: Mars has a tenth of the Earth’s mass and lost its atmosphere. Does Proxima b have an atmosphere? If so, the atmosphere and any surface ocean it sustains, will moderate the temperature contrast between its permanent day and night sides. In collaboration with Laura Kreidberg, we showed [2] that the James Webb Space Telescope, scheduled for launch in October 2018, will be able to distinguish between the temperature contrast expected if Proxima b is bare rock compared to the case where its climate is moderated by an atmosphere.

    NASA/ESA/CSA Webb Telescope annotated

    Proxima Centauri is a red dwarf star with 12% of the mass of the Sun. Another dwarf star, TRAPPIST-1, with 8% of the solar mass, was discovered recently [3],[4] to host 3 habitable planets out of a total of 7 and if life forms in one of the three it will likely spread to the others [5].

    The TRAPPIST-1 star, an ultracool dwarf, is orbited by seven Earth-size planets (NASA).

    ESO Belgian robotic Trappist National Telescope at Cerro La Silla, Chile interior

    ESO Belgian robotic Trappist-South National Telescope at Cerro La Silla, Chile

    Such dwarf stars have a lifetime that is up to a thousand times longer than the Sun. Hence, they provide excellent prospects for life in the distant future, a trillion years from now, long after the Sun will die and turn into an Earth-size cold remnant, known as a white dwarf. I therefore advise my wealthy friends to buy real estate on Proxima b, since its value is likely to go up dramatically in the future. But this also raises an important scientific question: is life most likely to emerge at the present cosmic time near a star like the Sun? By studying the habitability of the Universe throughout cosmic history from the birth of the first stars 30 million years after the Big Bang to the death of the last stars in ten trillion years, I concluded [6],[7] that unless habitability around low mass stars is suppressed, life is most likely to exist near dwarf stars like Proxima or TRAPPIST-1 ten trillion years from now. This highlights the importance of searching for life around these nearby red dwarf stars, namely the Red Dots campaign. Finding bio-signatures in the atmospheres of transiting Earth-mass planets around such stars will determine whether present-day life is indeed premature or typical from a cosmic perspective.

    References [no links provided]:

    Anglada-Escudé G. et al. “A Terrestrial Candidate in a Temperate Orbit Around Proxima Centauri”, Nature, 536, 437 (2016).
    Kreidberg, L. & Loeb, A. “Prospects for Characterising the Atmosphere of Proxima b”, ApJ, 832, L12 (2016).
    Gillon, M. et al. “Temperate Earth-Sized Planets Transiting a Nearby Ultracool Dwarf Star”, Nature, 533, 221 (2016).
    Gillon, M, et al. “Seven temperate terretrial planets around the nearby ultracool dwarf star TRAPPIST-1”, Nature, 542, 456–460
    Lingam, M., & Loeb, A. “Enhanced Interplanetary Panspermia in the TRAPPIST-1 System”, PNAS, in press (2017); arXiv: 1703.00878.
    Loeb, A., Batista, R. A., & Sloan, D. “Relative Likelihood for Life as a Function of Cosmic Time”, JCAP, 8, 40 (2016). “
    Loeb, A. “On the Habitability of Our Universe”, chapter for the book “Consolidation of Fine Tuning”, edited by R. Davies, J. Silk and D. Sloan (Oxford University, 2017); arXiv:1606.0892

    See the full article here .

    It seems to me that the author should have made mention of the Breakthrough Listen Project, a modest initiative using ground based telescopic assets.

    Lick Automated Planet Finder telescope, Mount Hamilton, CA, USA



    GBO radio telescope, Green Bank, West Virginia, USA

    and

    CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

    Not to mention also missing

    Breakthrough Starshot Initiative Observatories

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

    SPACEOBS, the San Pedro de Atacama Celestial Explorations Observatory is located at 2450m above sea level, north of the Atacama Desert, in Chile, near to the village of San Pedro de Atacama and close to the border with Bolivia and Argentina

    SNO Sierra Nevada Observatory is a high elevation observatory 2900m above the sea level located in the Sierra Nevada mountain range in Granada Spain and operated maintained and supplied by IAC

    Teide Observatory in Tenerife Spain, home of two 40 cm LCO telescopes

    Observatori Astronòmic del Montsec (OAdM), located in the town of Sant Esteve de la Sarga (Pallars Jussà), 1,570 meters on the sea level

    Bayfordbury Observatory,approximately 6 miles from the main campus of the University of Hertfordshire

    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.

     
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