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  • richardmitnick 2:19 pm on August 18, 2017 Permalink | Reply
    Tags: , , , Brown dwarf binaries, CFHT, , Goal was to measure the masses of the objects in these binaries, ,   

    From CFHT: “Astronomers prove what separates true stars from wannabes” 

    CFHT icon
    Canada France Hawaii Telescope

    June 5, 2017 [Just presented in social media.]

    Dr. Roy Gal
    University of Hawaii at Manoa
    +1 301-728-8637
    rgal@ifa.hawaii.edu

    Dr. Trent Dupuy
    The University of Texas at Austin
    +1 318-344-0975
    tdupuy@astro.as.utexas.edu

    Dr. Michael Liu
    University of Hawaii at Manoa
    +1 808-956-6666
    mliu@ifa.hawaii.edu

    “When we look up and see the stars shining at night, we are seeing only part of the story,” said Trent Dupuy of the University of Texas at Austin and a graduate of the Institute for Astronomy at the University of Hawaii at Manoa. “Not everything that could be a star ‘makes it,’ and figuring out why this process sometimes fails is just as important as understanding when it succeeds.”

    1
    Professor Michael Liu stands in front of WIRCam, CFHT’s infrared camera that was used for this decade long study.

    Dupuy is the lead author of the study and will present his research today in a news conference at the semi-annual meeting of the American Astronomical Society in Austin.

    Stars form when a cloud of gas and dust collapses due to gravity, and the resulting ball of matter becomes hot enough and dense enough to sustain nuclear fusion at its core. Fusion produces huge amounts of energy — it’s what makes stars shine. In the Sun’s case, it’s what makes most life on Earth possible.

    But not all collapsing gas clouds are created equal. Sometimes, the collapsing cloud makes a ball that isn’t dense enough to ignite fusion. These ‘failed stars’ are known as brown dwarfs.

    This simple division between stars and brown dwarfs has been used for a long time. In fact, astronomers have had theories about how massive the collapsing ball has to be in order to form a star (or not) for over 50 years. However, the dividing line in mass has never been confirmed by experiment.

    Now, astronomers Dupuy and Michael Liu of the University of Hawaii, who is a co-author of the study, have done just that. They found that an object must weigh at least 70 Jupiters in order to start hydrogen fusion. If it weighs less, the star does not ignite and becomes a brown dwarf instead.

    How did they reach that conclusion? For a decade, the two studied 31 faint brown dwarf binaries (pairs of these objects that orbit each other) using two powerful telescopes in Hawaii — the W. M. Keck Observatory and Canada-France-Hawaii telescopes — as well as data from the Hubble Space Telescope.


    Keck Observatory, Maunakea, Hawaii, USA

    NASA/ESA Hubble Telescope

    Their goal was to measure the masses of the objects in these binaries, since mass defines the boundary between stars and brown dwarfs. Astronomers have been using binaries to measure masses of stars for more than a century. To determine the masses of a binary, one measures the size and speed of the stars’ orbits around an invisible point between them where the pull of gravity is equal (known as the “center of mass”). However, binary brown dwarfs orbit much more slowly than binary stars, due to their lower masses. And because brown dwarfs are dimmer than stars, they can only be well studied with the world’s most powerful telescopes.

    To measure masses, Dupuy and Liu collected images of the brown-dwarf binaries over several years, tracking their orbital motions using high-precision observations. They used the 10-meter Keck Observatory telescope, along with its laser guide star adaptive optics system, and the Hubble Space Telescope, to obtain the extremely sharp images needed to distinguish the light from each object in the pair.

    However, the price of such zoomed-in, high-resolution images is that there is no reference frame to identify the center of mass. Wide-field images from the Canada-France-Hawaii Telescope containing hundreds of stars provided the reference grid needed to measure the center of mass for every binary. The precise positions needed to make these measurements are one of the specialties of WIRCam, the wide field infrared camera at CFHT. “Working with Trent Dupuy and Mike Liu over the last decade has not only benefited their work but our understanding of what is possible with WIRCam as well” says Daniel Devost, director of science operations at CFHT. “This is one of the first programs I worked on when I started at CFHT so this makes this discovery even more exciting.”

    The result of the decade-long observing program is the first large sample of brown dwarf masses. The information they have assembled has allowed them to draw a number of conclusions about what distinguishes stars from brown dwarfs.

    Objects heavier than 70 Jupiter masses are not cold enough to be brown dwarfs, implying that they are all stars powered by nuclear fusion. Therefore 70 Jupiters is the critical mass below which objects are fated to be brown dwarfs. This minimum mass is somewhat lower than theories had predicted but still consistent with the latest models of brown dwarf evolution.

    In addition to the mass cutoff, they discovered a surface temperature cutoff. Any object cooler than 1,600 Kelvin (about 2,400 degrees Fahrenheit) is not a star, but a brown dwarf.

    This new work will help astronomers understand the conditions under which stars form and evolve — or sometimes fail. In turn, the success or failure of star formation has an impact on how, where, and why solar systems form.

    “As they say, good things come to those who wait. While we’ve had many interesting brown dwarf results over the past 10 years, this large sample of masses is the big payoff. These measurements will be fundamental to understanding both brown dwarfs and stars for a very long time,” concludes Liu.

    This research will be published in The Astrophysical Journal Supplement.

    See the full article here .
    See the U Hawaii press release here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The CFH observatory hosts a world-class, 3.6 meter optical/infrared telescope. The observatory is located atop the summit of Mauna Kea, a 4200 meter, dormant volcano located on the island of Hawaii. The CFH Telescope became operational in 1979. The mission of CFHT is to provide for its user community a versatile and state-of-the-art astronomical observing facility which is well matched to the scientific goals of that community and which fully exploits the potential of the Mauna Kea site.

    CFHT Telescope
    CFHT Interior
    CFHT

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  • richardmitnick 5:08 pm on July 17, 2017 Permalink | Reply
    Tags: , , , , CFHT, , , ,   

    From Webb: “Birth of Stars & Protoplanetary Systems” 

    NASA Webb Header

    NASA Webb Telescope

    James Webb Space Telescope

    1
    The Pillars of Creation in the Eagle Nebula captured in visible light by Hubble. Stellar nurseries are hidden within the towers of dust and gas. Credit: NASA/ESA/Hubble Heritage Team (STScI/AURA)/J. Hester, P. Scowen (Arizona State U.)

    Inside the Pillars of Creation

    While this image is spectacular, there are actually stars that Hubble can’t see inside those pillars of dust. And that’s because the visible light emitted by those stars is being obscured by the dust. But what if we used a telescope sensitive to infrared light to look at this nebula?

    The next image is another Hubble view, but this time in near-infrared. In the infrared more structure within the dust clouds is revealed and hidden stars have now become apparent. (And if Hubble, which is optimized for visible light, can capture a near-infrared image like this, imagine what JWST, which is optimized for near-infrared and 100x more powerful than Hubble, will do!)

    Another nebula, the “Mystic Mountains” of the Carina Nebula, shown in two Hubble images, one in visible light (left) and one in infrared (right).
    In the infrared image, we can see more stars that just weren’t visible before. Why is this?

    2
    The Pillars of Creation in the Eagle Nebula captured in infrared light by Hubble. The light from young stars being formed pierce the clouds of dust and gas in the infrared. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

    3
    Comparison of the Carina Nebula in visible light (left) and infrared (left), both images by Hubble. Credit: NASA/ESA/M. Livio & Hubble 20th Anniversary Team (STScI)

    How Do Infrared Cameras Work?

    We can try a thought experiment. What if you were to put your arm into a garbage bag? Your arm is hidden. Invisible.

    But what if you looked at your arm and the garbage bag with an infrared camera? Remember that infrared light is essentially heat. And that while your eyes may not be able to pick up the warmth of your arm underneath the cooler plastic of the bag, an infrared camera can. An infrared camera can see right through the bag!

    4
    5

    6
    ALMA image of the young star HL Tau and its protoplanetary disk. This best image ever of planet formation reveals multiple rings and gaps that herald the presence of emerging planets as they sweep their orbits clear of dust and gas. Credit: ALMA (NRAO/ESO/NAOJ); C. Brogan, B. Saxton (NRAO/AUI/NSF)

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    The Dusty Cocoons of Star and Planet Formation

    JWST’s amazing imaging and spectroscopy capabilities will allow us to study stars as they are forming in their dusty cocoons. Additionally, it will be able to image disks of heated material around these young stars, which can indicate the beginnings of planetary systems, and study organic molecules that are important for life to develop.

    _________________________________________________________________
    Key Questions

    JWST will address several key questions to help us unravel the story of the star and planet formation:

    How do clouds of gas and dust collapse to form stars?
    Why do most stars form in groups?
    Exactly how do planetary systems form?
    How do stars evolve and release the heavy elements they produce back into space for recycling into new generations of stars and planets?

    7
    Infrared Spitzer image of a star-forming region. Credit: NASA/JPL-Caltech/ Harvard-Smithsonian CfA

    NASA/Spitzer Telescope

    JWST’s Role in Answering These Questions

    To unravel the birth and early evolution of stars and planets, we need to be able to peer into the hearts of dense and dusty cloud cores where star formation begins. These regions cannot be observed at visible light wavelengths as the dust would make such regions opaque and must be observed at infrared wavelengths.

    Stars, like our Sun, can be thought of as “basic particles” of the Universe, just as atoms are “basic particles” of matter. Groups of stars make up galaxies, while planets and ultimately life arise around stars. Although stars have been the main topic of astronomy for thousands of years, we have begun to understand them in detail only in recent times through the advent of powerful telescopes and computers.

    A hundred years ago, scientists did not know that stars are powered by nuclear fusion, and 50 years ago they did not know that stars are continually forming in the Universe. Researchers still do not know the details of how clouds of gas and dust collapse to form stars, or why most stars form in groups, or exactly how planetary systems form. Young stars within a star-forming region interact with each other in complex ways. The details of how they evolve and release the heavy elements they produce back into space for recycling into new generations of stars and planets remains to be determined through a combination of observation and theory.

    8
    The stages of solar system formation. Credit: Shu et al. 1987

    The stages of solar system formation are illustrated to the right: starting with a protostar embedded in a gas cloud (upper left of diagram), to an early star with a circumstellar disk (upper right), to a star surrounded by small “planetesimals” which are starting to clump together (lower left) to a solar system like ours today.

    The continual discovery of new and unusual planetary systems has made scientists re-think their ideas and theories about how planets are formed. Scientists realize that to get a better understanding of how planets form, they need to have more observations of planets around young stars, and more observations of leftover debris around stars, which can come together and form planets.

    _________________________________________________________________

    Related Content
    More Comparison Images

    Here’s is another stunning comparison of visible versus infrared light views of the same object – the gorgeous Horsehead Nebula:

    9
    The Horsehead Nebula in visible light, captured by the Canada-France Hawaii Telescope. Credit: NASA

    Visible Light Horsehead Nebula


    CFHT Telescope, Maunakea, Hawaii, USA

    Infrared Light Horsehead Nebula

    9
    The Horsehead Nebula in infrared light, captured by the Hubble Space Telescope. Credit: NASA/Space Telescope Science Institute (STScI)

    NASA/ESA Hubble Telescope

    Related Video

    This video shows how JWST will peer inside dusty knots where the youngest stars and planets are forming.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The James Webb Space Telescope will be a large infrared telescope with a 6.5-meter primary mirror. Launch is planned for later in the decade.

    Webb telescope will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.

    Webb telescope was formerly known as the “Next Generation Space Telescope” (NGST); it was renamed in Sept. 2002 after a former NASA administrator, James Webb.

    Webb is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center is managing the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute will operate Webb after launch.

    Several innovative technologies have been developed for Webb. These include a folding, segmented primary mirror, adjusted to shape after launch; ultra-lightweight beryllium optics; detectors able to record extremely weak signals, microshutters that enable programmable object selection for the spectrograph; and a cryocooler for cooling the mid-IR detectors to 7K.

    There will be four science instruments on Webb: the Near InfraRed Camera (NIRCam), the Near InfraRed Spectrograph (NIRspec), the Mid-InfraRed Instrument (MIRI), and the Fine Guidance Sensor/ Near InfraRed Imager and Slitless Spectrograph (FGS-NIRISS). Webb’s instruments will be designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range. It will be sensitive to light from 0.6 to 28 micrometers in wavelength.
    Webb has four main science themes: The End of the Dark Ages: First Light and Reionization, The Assembly of Galaxies, The Birth of Stars and Protoplanetary Systems, and Planetary Systems and the Origins of Life.

    Launch is scheduled for later in the decade on an Ariane 5 rocket. The launch will be from Arianespace’s ELA-3 launch complex at European Spaceport located near Kourou, French Guiana. Webb will be located at the second Lagrange point, about a million miles from the Earth.

    NASA image

    ESA50 Logo large

    Canadian Space Agency

     
  • richardmitnick 2:33 pm on June 6, 2017 Permalink | Reply
    Tags: , , , , CFHT, ,   

    From CFHT: “Astronomers prove what separates true stars from wannabes” 

    CFHT icon
    Canada France Hawaii Telescope

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    HONOLULU — Astronomers have shown what separates real stars from the wannabes. Not in Hollywood, but out in the universe.

    6.5.17

    Dr. Roy Gal
    University of Hawaii at Manoa
    +1 301-728-8637
    rgal@ifa.hawaii.edu

    Dr. Trent Dupuy
    The University of Texas at Austin
    +1 318-344-0975
    tdupuy@astro.as.utexas.edu

    Dr. Michael Liu
    University of Hawaii at Manoa
    +1 808-956-6666
    mliu@ifa.hawaii.edu

    Mari-Ela Chock
    W. M. Keck Observatory
    808-554-0567
    mchock@keck.hawaii.edu

    1
    Professor Michael Liu stands in front of WIRCam, CFHT’s infrared camera that was used for this decade long study.

    “When we look up and see the stars shining at night, we are seeing only part of the story,” said Trent Dupuy of the University of Texas at Austin and a graduate of the Institute for Astronomy at the University of Hawaii at Manoa.

    “Not everything that could be a star ‘makes it,’ and figuring out why this process sometimes fails is just as important as understanding when it succeeds.

    Dupuy is the lead author of the study and will present his research today in a news conference at the semi-annual meeting of the American Astronomical Society in Austin.

    Stars form when a cloud of gas and dust collapses due to gravity, and the resulting ball of matter becomes hot enough and dense enough to sustain nuclear fusion at its core. Fusion produces huge amounts of energy — it’s what makes stars shine. In the Sun’s case, it’s what makes most life on Earth possible.

    But not all collapsing gas clouds are created equal. Sometimes, the collapsing cloud makes a ball that isn’t dense enough to ignite fusion. These ‘failed stars’ are known as brown dwarfs.

    This simple division between stars and brown dwarfs has been used for a long time. In fact, astronomers have had theories about how massive the collapsing ball has to be in order to form a star (or not) for over 50 years. However, the dividing line in mass has never been confirmed by experiment.

    Now, astronomers Dupuy and Michael Liu of the University of Hawaii, who is a co-author of the study, have done just that. They found that an object must weigh at least 70 Jupiters in order to start hydrogen fusion. If it weighs less, the star does not ignite and becomes a brown dwarf instead.

    How did they reach that conclusion? For a decade, the two studied 31 faint brown dwarf binaries (pairs of these objects that orbit each other) using two powerful telescopes in Hawaii — the W. M. Keck Observatory and Canada-France-Hawaii telescopes — as well as data from the Hubble Space Telescope.

    4
    Magnificent Failures: Discovery of a rare brown-dwarf eclipsing binary. http://astro.phy.vanderbilt.edu/~stassuk/research.htm

    NASA/ESA Hubble Telescope

    Their goal was to measure the masses of the objects in these binaries, since mass defines the boundary between stars and brown dwarfs. Astronomers have been using binaries to measure masses of stars for more than a century. To determine the masses of a binary, one measures the size and speed of the stars’ orbits around an invisible point between them where the pull of gravity is equal (known as the “center of mass”). However, binary brown dwarfs orbit much more slowly than binary stars, due to their lower masses. And because brown dwarfs are dimmer than stars, they can only be well studied with the world’s most powerful telescopes.

    To measure masses, Dupuy and Liu collected images of the brown-dwarf binaries over several years, tracking their orbital motions using high-precision observations. They used the 10-meter Keck Observatory telescope, along with its laser guide star adaptive optics system, and the Hubble Space Telescope, to obtain the extremely sharp images needed to distinguish the light from each object in the pair.

    However, the price of such zoomed-in, high-resolution images is that there is no reference frame to identify the center of mass. Wide-field images from the Canada-France-Hawaii Telescope containing hundreds of stars provided the reference grid needed to measure the center of mass for every binary. The precise positions needed to make these measurements are one of the specialties of WIRCam, the wide field infrared camera at CFHT. “Working with Trent Dupuy and Mike Liu over the last decade has not only benefited their work but our understanding of what is possible with WIRCam as well” says Daniel Devost, director of science operations at CFHT. “This is one of the first programs I worked on when I started at CFHT so this makes this discovery even more exciting.”

    The result of the decade-long observing program is the first large sample of brown dwarf masses. The information they have assembled has allowed them to draw a number of conclusions about what distinguishes stars from brown dwarfs.

    Objects heavier than 70 Jupiter masses are not cold enough to be brown dwarfs, implying that they are all stars powered by nuclear fusion. Therefore 70 Jupiters is the critical mass below which objects are fated to be brown dwarfs. This minimum mass is somewhat lower than theories had predicted but still consistent with the latest models of brown dwarf evolution.

    In addition to the mass cutoff, they discovered a surface temperature cutoff. Any object cooler than 1,600 Kelvin (about 2,400 degrees Fahrenheit) is not a star, but a brown dwarf.

    This new work will help astronomers understand the conditions under which stars form and evolve — or sometimes fail. In turn, the success or failure of star formation has an impact on how, where, and why solar systems form.

    “As they say, good things come to those who wait. While we’ve had many interesting brown dwarf results over the past 10 years, this large sample of masses is the big payoff. These measurements will be fundamental to understanding both brown dwarfs and stars for a very long time,” concludes Liu.

    This research will be published in The Astrophysical Journal Supplement.
    Additional information

    University of Hawaii press release.
    Scientific Paper on the arXiv

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Keck Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
    Keck UCal

    The CFH observatory hosts a world-class, 3.6 meter optical/infrared telescope. The observatory is located atop the summit of Mauna Kea, a 4200 meter, dormant volcano located on the island of Hawaii. The CFH Telescope became operational in 1979. The mission of CFHT is to provide for its user community a versatile and state-of-the-art astronomical observing facility which is well matched to the scientific goals of that community and which fully exploits the potential of the Mauna Kea site.

    CFHT Telescope
    CFHT Interior
    CFHT

     
  • richardmitnick 4:38 pm on October 5, 2016 Permalink | Reply
    Tags: , , CFHT, Malin 1,   

    From CFHT: “A new look at the largest known disk galaxy” 

    CFHT icon
    Canada France Hawaii Telescope

    10.5.16
    Contact
    Dr. Samuel Boissier
    Laboratoire d’Astrophysique de Marseille (AMU, CNRS).
    Phone number: +33 4 91 05 59 37
    samuel.boissier@lam.fr

    1
    Combination of 4 NGVS images of Malin 1, obtained with MegaCam camera on CFHT. An indication of the size is given in the figure to show the amazing size of the disk of the galaxy (in comparison, the Milky Way has only a diameter around 30 kpc). Image Credit: Boissier/A&A/ESO/CFHT

    CFHT MegaCam
    CFHT MegaCam

    In a publication recently accepted in Astronomy and Astrophysics, an international team involving French researchers from the Laboratoire d’Astrophysique de Marseille and Canadian researchers from NRC Herzberg and Queens University have studied Malin 1, a nearby galaxy that has been known only since the eighty’s and that shows an extremely large disk of gas and stars. The new observations of Malin 1, a prototype of the class of “giant low surface brightness galaxies” allowed the team to obtain new results in contradiction with one of the hypotheses concerning the formation of this type of galaxies.

    Because they are very diffuse and of low surface brightness, giant low surface brightness galaxies, yet massive, are difficult to observe and are still poorly known. They could represent a significant percentage of the galaxies in the universe, especially because we could have missed such objects in our galaxy surveys. It is thus important do study them and understand their formation and evolution. This is now possible owing to the new generation of telescopes and modern detectors, with higher sensitivity to low surface brightness than in the past.

    This paper presents for the first time deep images obtained at 6 different wavelengths, from the UV of the GUViCS project to the optical and near-infrared obtained in the context of the Next Generation Virgo Survey with MegaCam on CFHT. Originally, these large observational campaigns were planned to study the Virgo cluster, but they also allow us to study background objects like Malin 1. The images offer us a new view of this spectacular galaxy, the largest galactic disk known, with a diameter above 250 kilo-parsec (in comparison, our Milky Way is only about 30 kpc wide).

    The team of researchers extracted from these data the variation of the luminosity with the distance to the center of the galaxy, as well as the variation of the colors (corresponding to the ratios between the luminosity at various wavelengths). These colors strongly depends on the star formation history. The comparison of the observations with predictions of various numerical models allowed the team to estimate for the first time what must have been the history of star formation in the giant disk of Malin 1. It suggests that the giant disk has been in place for several Gyr, and that star formation proceed at a regular long-term rhythm despite the very low density.

    This result is important as it clearly contradicts a scenario proposed a few years ago predicting that these giant galaxies are formed during violent interactions. Moreover, in the context of the cosmological formation of galaxies, numerous fusions and interaction should have perturbed the disk of Malin 1. The formation of such a structure and its survival for very long time offers then a challenge for cosmological simulations of the formation of galaxies.

    What is the future of Malin 1? The giant disk contains a large quantity of gas in which star formation will keep proceeding at a low rate for billions of years, increasing progressively the stellar mass of the galaxy. Unless another galaxy comes in the picture to interact with Malin 1 and totally change its destiny. Few galaxies, however, may play this role as Malin 1 is a relatively isolated galaxy.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The CFH observatory hosts a world-class, 3.6 meter optical/infrared telescope. The observatory is located atop the summit of Mauna Kea, a 4200 meter, dormant volcano located on the island of Hawaii. The CFH Telescope became operational in 1979. The mission of CFHT is to provide for its user community a versatile and state-of-the-art astronomical observing facility which is well matched to the scientific goals of that community and which fully exploits the potential of the Mauna Kea site.

    CFHT Telescope
    CFHT Interior
    CFHT

     
  • richardmitnick 10:10 am on October 1, 2016 Permalink | Reply
    Tags: A galaxy in distress: the spectacular tails of ionized gas in NGC 4569 the most massive spiral galaxy in the Virgo cluster, , , CFHT,   

    From CFHT: “A galaxy in distress: the spectacular tails of ionized gas in NGC 4569, the most massive spiral galaxy in the Virgo cluster” 

    CFHT icon
    Canada France Hawaii Telescope

    Feb 8 2016 [Just appeared in social media.]
    Alessandro Boselli
    Laboratoire d’Astrophysique de Marseille
    38, rue Joliot-Curie
    F-13388 Marseille cedex 13
    France

    An international team led by researchers from the Laboratoire d’Astrophysique de Marseille (LAM) has used MegaCam on CFHT to observe NGC 4569, the most massive spiral galaxy in the Virgo cluster. They observed, for the first time, spectacular tails of ionized gas that extend for over 300,000 light years, five times larger than NGC 4569 itself! This observation confirms that ram pressure stripping due to the intracluster medium is depriving NGC 4569 of its gas reservoir. This important constraint must be taken into account in any cosmological model striving to incorporate the effect of environment on the evolution of galaxies. The result also shows that MegaCam at CFHT is now a second-to-none world-class facility to study gas stripping and opens up a promising new avenue for understanding the role of environment in the evolution of galaxies.

    CFHT MegaCam
    CFHT MegaCam

    1
    The colour image of the galaxy NGC 4569 in the Virgo cluster, obtained with MegaCam at the CFHT. The red filaments at the right of the galaxy show the ionised gas removed by ram pressure. This is about 95% of the gas reservoir of the galaxy needed to feed the formation of new stars (image ©2015 CFHT/Coelum).

    Galaxies are not distributed uniformly throughout the universe. Some are found in dense clusters that can contain hundred to thousands of galaxies. Astrophysicists suspect that living in a cluster environment can have a strong influence in the way galaxies evolve. The tell-tail signs have long been recognized: for instance, compared to less dense regions, clusters contain proportionally more elliptical galaxies (spheroidal systems with little to no gas and dust) and fewer spirals (gas rich disky systems in which new stars are continuously formed from the gas in the interstellar medium). And even the few spiral galaxies found in clusters generally contain less gas and have an older population of stars than isolated spiral galaxies.

    Several mechanisms have been proposed to explain the difference observed between galaxies in different environments. First, when two galaxies interact, tidal forces tend to rip apart and disrupt the outermost, less gravitationally bound and most diffuse parts. A second mechanism is the “dynamical pressure” exerted on the interstellar medium of a galaxy as it travels through the hot, diffuse medium that permeates the space in between galaxies, a process known as `ram pressure stripping’ (a biker travelling at high speed would experience a similar kind of pressure from the ambient air!). These two processes are able to lift gas from the disks of spiral galaxies, and therefore inhibit the formation of new stars. There is also a third mechanism that is thought to affect mostly the most massive galaxies: these galaxies host very massive black holes at their centres, and the energy liberated by the accretion onto these black holes, injected into the surrounding medium, can unbind the gas.

    Identifying which of these processes is dominant is critical to constrain cosmological simulations that follow the evolution of galaxies. Observationally, however, observing the low density gas as it is being stripped is a tremendous challenge. The MegaCam Camera on the Canada France Hawaii Telescope (CFHT) has recently been equipped with a new, high efficient narrow-band filter that isolates the H-alpha emission line from the ionized gas, allowing it to be detected with high efficiency.

    An international team led by researchers from the Laboratoire d’Astrophysique de Marseille (LAM) has used this instrument to observe NGC 4569, the most massive spiral galaxy in the Virgo cluster (at 45 million light years, the massive cluster of galaxies closest to the Milky Way). The Virgo cluster is still evolving, and therefore offers the opportunity to observe the transformation of galaxies as it takes place. NGC 4569 is moving through the cluster at a staggering 1200 km/s. The H-alpha image obtained with MegaCam at CFHT shows for the first time spectacular tails of ionized gas that extend for over 300,000 light years, five times larger than NGC 4569 itself ! This observation confirms that ram pressure stripping due to the intracluster medium is depriving NGC 4569 of its gas reservoir. An estimate of the mass of gas in these tails shows that 95% of the interstellar medium has already been removed from the disk of the galaxy, greatly limiting its ability to form new stars.

    For a galaxy as massive as NGC 4569, it is perhaps surprising that internal gravitational forces are not strong enough to hold the gas together, counteracting the action of ram pressure stripping. Indeed, in cosmological models, it is hypothesised that in such massive galaxies, it is the activity related to the central supermassive black hole to cause the gas to be lost. The new observations show instead that the dominant effect is ram pressure: this important constraint must be taken into account in any cosmological model striving to incorporate the effect of environment on the evolution of galaxies.

    The result also shows that MegaCam at CFHT is now a second-to-none world-class facility to study gas stripping and opens up a promising new avenue for understanding the role of environment in the evolution of galaxies.

    Scientific article

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The CFH observatory hosts a world-class, 3.6 meter optical/infrared telescope. The observatory is located atop the summit of Mauna Kea, a 4200 meter, dormant volcano located on the island of Hawaii. The CFH Telescope became operational in 1979. The mission of CFHT is to provide for its user community a versatile and state-of-the-art astronomical observing facility which is well matched to the scientific goals of that community and which fully exploits the potential of the Mauna Kea site.

    CFHT Telescope
    CFHT Interior
    CFHT

     
  • richardmitnick 9:50 am on October 1, 2016 Permalink | Reply
    Tags: , , , CFHT,   

    From CFHT: “An unexpected use of large optical telescope: Imaging the small scale structure of the diffuse interstellar medium” 

    CFHT icon
    Canada France Hawaii Telescope

    7.12.16 [Just appeared in social media.]
    Information:
    Media contact
    Mary Beth Laychak
    Canada-France-Hawaii Telescope
    (808) 885-3121
    mary@cfht.hawaii.edu

    Science contacts
    Marc-Antoine Miville-Deschênes
    IAS (CNRS/Université Paris Sud/Université Paris-Saclay)
    mamd@ias.u-psud.fr
    Tel: 01 69 85 85 79

    Pierre-Alain Duc
    AIM (CEA/CNRS/Université Paris Diderot/Université Paris-Saclay)
    paduc@cea.fr
    Tel:01 69 08 92 68

    By combining multi-wavelength data obtained from space with Planck and WISE, and from the ground with MegaCam on CFHT, a team of researchers has revealed the structure of the diffuse interstellar medium over several square degrees with unprecedented details. In particular, this study reveals the statistical properties of interstellar turbulence over a wide range of scales, from 0.01 to 10 pc.

    CFHT MegaCam
    CFHT MegaCam

    ESA/Planck
    ESA/Planck

    NASA/WISE Telescope
    NASA/WISE Telescope

    1
    Optical images in true colours of the cirrus field obtained with MegaCam on the CFHT. Image credits: MATLAS collaboration, Pierre-Alain Duc.

    The main innovation of this work is the use of a large optical telescope (the CFHT) to study the structure of the interstellar medium at high resolution and on a large area on the sky, something that is very challenging to obtain with more classical observations done in the infrared. This mapping of these interstellar cirrus clouds located within a few hundred parsec from the Sun can be done because interstellar dust grains scatter starlight. This scattered light has been detected for decades by optical telescopes. Here it is the first time that is exploited scientifically to study the structure of interstellar clouds which is composed of faint filamentary structures of various sizes. The result obtained benefit from specific image processing and data acquisition techniques developed in the context of the MATLAS Large Program at CFHT that aims at detecting faint diffuse emission around galaxies.

    2
    Combined power spectrum : black is Planck radiance, red is WISE and blue is MegaCam. The units of the y axis are arbitrary; each power spectrum was scaled in order to match the others. For each power spectrum, we show data points corresponding to scales larger than the beam and where the power is above the noise component. The data points shown here are noise subtracted and divided by the beam function. The best fit gives P(k) ~ k^(2.9±0.1). Figure from Miville-Deschênes et al. 2016.

    One advantage of the high angular resolution provided by the CFHT data is to eventually reach the angular scale at which turbulent energy dissipates. Understanding the exact process by which kinetic energy is dissipated and heats gas is essential. It is key in the formation of dense structures that lead to the formation of stars. For instance, recent studies based on Herschel observations of molecular clouds have revealed the presence of filaments with widths of 0.1 pc that seem constant whatever their mass. This observational fact has been attributed to the energy dissipation process, namely ambipolar diffusion (friction between neutrals and ions). The present study shows that the dissipation scale in the interstellar medium is smaller than 0.01 pc which brings important constraints on the exact process resposible for this dissipation.

    These results emphasize the fact that scattered light from cirrus, an important source of pollution for deep imaging destined to mapping diffuse structures around massive galaxies, is carrying potentially precious information about the nature of the physical processes involved in the evolution of matter in our own galaxy.

    Additional information
    CNRS/INSU press release (In French only)
    Scientific paper

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The CFH observatory hosts a world-class, 3.6 meter optical/infrared telescope. The observatory is located atop the summit of Mauna Kea, a 4200 meter, dormant volcano located on the island of Hawaii. The CFH Telescope became operational in 1979. The mission of CFHT is to provide for its user community a versatile and state-of-the-art astronomical observing facility which is well matched to the scientific goals of that community and which fully exploits the potential of the Mauna Kea site.

    CFHT Telescope
    CFHT Interior
    CFHT

     
  • richardmitnick 9:16 am on October 1, 2016 Permalink | Reply
    Tags: , , CFHT, Dwarf planet designated 2015 RR245,   

    From CFHT: “New Distant Dwarf Planet Beyond Neptune” 

    CFHT icon
    Canada France Hawaii Telescope

    July 11, 2016 [Just appeared in social media.]
    Media contacts:
    Mary Beth Laychak
    Canada-France-Hawaii Telescope
    (808) 885-3121
    mary@cfht.hawaii.edu

    Thandi Fletcher
    The University of British Columbia
    (604) 822-2234
    thandi.fletcher@ubc.ca

    Science contacts:
    Dr. Michele Bannister
    Postdoctoral Fellow with the Outer Solar System Origins Survey
    Department of Physics and Astronomy
    University of Victoria, Victoria BC
    micheleb@uvic.ca
    tel: +1 250 580 3085

    Dr. Jean-Marc Petit
    Institut UTINAM – UMR CNRS 6213
    Observatoire de Besancon
    41 bis Avenue de l’Observatoire BP 1615
    Jean-Marc.Petit@normalesup.org
    tel: (33) [0]695 207 174

    Dr Ying-Tung (Charles) Chen 陳英同, IAA
    Academia Sinica, Taipei
    ytchen@asiaa.sinica.edu.tw
    tel: +886-2-2366-5356

    An international team of astronomers have discovered a new dwarf planet orbiting in the disk of small icy worlds beyond Neptune. The new object is roughly 700 kilometers in size and has one of the largest orbits for a dwarf planet. Designated 2015 RR245 by the International Astronomical Union’s Minor Planet Center, it was found using the Canada-France-Hawaii Telescope on Maunakea, Hawaii, as part of the ongoing Outer Solar System Origins Survey (OSSOS).

    1
    Discovery images of RR245. The images show RR245’s slow motion across the sky over three hours. Credit OSSOS team.

    “The icy worlds beyond Neptune trace how the giant planets formed and then moved out from the Sun. They let us piece together the history of our Solar System. But almost all of these icy worlds are painfully small and faint: it’s really exciting to find one that’s large and bright enough that we can study it in detail.” said Dr Michele Bannister of the University of Victoria in British Columbia, who is a postdoctoral fellow with the Survey.

    National Research Council of Canada’s Dr JJ Kavelaars first sighted RR245 in February 2016 in the OSSOS images from September 2015.”There it was on the screen— this dot of light moving so slowly that it had to be at least twice as far as Neptune from the Sun.” said Bannister.

    The team became even more excited when they realized that the object’s orbit takes it more than 120 times further from the Sun than Earth. The size of RR245 is not yet exactly known, as its surface properties need further measurement. “It’s either small and shiny, or large and dull.” said Bannister.

    2
    Rendering of the orbit of RR245 (orange line). Objects as bright or brighter than RR245 are labeled. The blue circles show the projected orbits of the major planets. The Minor Planet Center describes the object as the 18th largest in the Kuiper Belt. Credit: Alex Parker OSSOS team.

    The vast majority of the dwarf planets like RR245 were destroyed or thrown from the Solar System in the chaos that ensued as the giant planets moved out to their present positions: RR245 is one of the few dwarf planets that has survived to the present day — along with Pluto and Eris, the largest known dwarf planets. RR245 now circles the Sun among the remnant population of tens of thousands of much smaller trans-Neptunian worlds, most of which orbit’s is unseen.

    Worlds that journey far from the Sun have exotic geology with landscapes made of many different frozen materials, as the recent flyby of Pluto by the New Horizons spacecraft showed.

    After hundreds of years further than 12 billion km (80 astronomical units, AU) from the Sun, RR245 is travelling towards its closest approach at 5 billion km (34 AU), which it will reach around 2096. RR245 has been on its highly elliptical orbit for at least the last 100 million years.

    As RR245 has only been observed for one of the seven hundred years it takes to orbit the Sun, where it came from and how its orbit will slowly evolve in the far future is still unknown; its precise orbit will be refined over the coming years, after which RR245 will be given a name. As discoverers, the OSSOS team can submit their preferred name for RR245 to the International Astronomical Union for consideration.

    “OSSOS was designed to map the orbital structure of the outer Solar System to decipher its history.” said Prof. Brett Gladman of the University of British Columbia in Vancouver. “While not designed to efficiently detect dwarf planets, we’re delighted to have found one on such an interesting orbit”.

    RR245 is the largest discovery and the only dwarf planet found by OSSOS, which has discovered more than five hundred new trans-Neptunian objects. “OSSOS is only possible due to the exceptional observing capabilities of the Canada-France-Hawaii Telescope. CFHT is located at one of the best optical observing locations on Earth, is equipped with an enormous wide-field imager, and can quickly adapt its observing each night to new discoveries we make. This facility is truly world leading.” said Gladman.

    Previous surveys have mapped almost all the brighter dwarf planets. 2015 RR245 may be one of the last large worlds beyond Neptune to be found until larger telescopes, such as LSST, come online in the mid 2020s.

    OSSOS involves a collaboration of fifty scientists at institutes and universities from around the world.

    OSSOS is based on observations obtained with MegaPrime/MegaCam, a joint project of the Canada-France-Hawaii Telescope (CFHT) and CEA/DAPNIA, and on data produced and hosted at the Canadian Astronomy Data Centre. CFHT is operated by the National Research Council of Canada, the Institute National des Sciences de l’Universe of the Centre National de la Recherche Scientifique of France, and the University of Hawaii, with OSSOS receiving additional access due to contributions from the Institute of Astronomy and Astrophysics, Academia Sinica, Taiwan.

    Additional information
    International Astronomical Union electronic discovery announcement
    International Astronomical Union orbital information
    Chinese release, ASIAA-Taiwan site
    OSSOS Project website

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The CFH observatory hosts a world-class, 3.6 meter optical/infrared telescope. The observatory is located atop the summit of Mauna Kea, a 4200 meter, dormant volcano located on the island of Hawaii. The CFH Telescope became operational in 1979. The mission of CFHT is to provide for its user community a versatile and state-of-the-art astronomical observing facility which is well matched to the scientific goals of that community and which fully exploits the potential of the Mauna Kea site.

    CFHT Telescope
    CFHT Interior
    CFHT

     
  • richardmitnick 10:45 am on July 26, 2016 Permalink | Reply
    Tags: An Extremely Weak Magnetic Field in a White Dwarf, , , CFHT,   

    From ING: “An Extremely Weak Magnetic Field in a White Dwarf” 

    Isaac Newton Group of Telescopes Logo
    Isaac Newton Group of Telescopes

    A team of astronomers reports the discovery of one of the very weakest magnetic fields ever securely detected in a white dwarf. The observation was made using the ISIS spectropolarimeter on the William Herschel Telescope (WHT), in just one hour of exposure time and using the red and the blue arms of the spectrograph. This is part of a large survey of bright white dwarfs to search for such weak magnetic fields.

    1
    First observation of Zeeman splitting in the core of Hydrogen alpha due to a field of about 60 kilogauss in WD2047+372. The ISIS observation is in blue, the ESPaDOnS observation (at higher resolving power) is shown in red. The circular polarisation spectrum is shown below the intensity profile, shifted up by +0.4 to facilitate comparison with the spectral line profile. The green lines bracketing the circular polarisation are ± one sigma. Figure extracted from Landstreet et al. (2016).

    The strength of the magnetic field found in LTT 16093 = WD2047+372 is only about 60 kilogauss (6 teslas), 2 or 3 orders of magnitude smaller than the typical fields of tens of megagauss found in a few percent of white dwarfs. The field was marginally detected in polarimetery, but clear Zeeman splitting into a triplet was present in the sharp core of Hydrogen alpha. This first detection using ISIS was confirmed by a spectropolarimetric observation a month later with the higher resolving power spectropolarimeter ESPaDOnS on the Canada-France-Hawaii Telescope [CFHT].

    CFHT ESPaDOns preferred
    CFHT ESPaDOns

    CFHT Telescope, Mauna Kea, Hawaii, USA
    CFHT Interior
    CFHT

    It is not yet understood how the magnetic fields of white dwarfs are formed, or how they evolve during white dwarf cooling. In spite of many detections of megagauss fields in white dwarfs, mostly very faint, little is known about the low-field regime, and very little modelling of the fields of individual white dwarfs is available. This current ISIS survey is intended to increase the very small sample and to provide data for detailed modelling, and ultimately to provide data to constrain field formation scenarios.

    It is found that ISIS is a very powerful tool for searches for such weak fields; it is able to detect fields of tens of kilogauss using either Hydrogen-alpha spectroscopy or spectropolarimetry of Hydrogen or Helium line wings, or both, in white dwarfs fainter than V = 15.

    More information:

    J. D. Landstreet, S. Bagnulo, A. Martin, and G. Valyavin, 2016, Discovery of an extremely weak magnetic field in the white dwarf LTT 16093 WD2047+372, A&A, 591, A80 [ADS ].

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    Isaac Newton Group telescopes
    Isaac Newton Group telescopes

    ING William Herschel Telescope
    ING William Herschel Interior
    ING William Herschel Telescope

     
  • richardmitnick 3:47 pm on July 12, 2016 Permalink | Reply
    Tags: , , , CFHT   

    From CFHT: “An unexpected use of large optical telescope… 

    CFHT icon
    Canada France Hawaii Telescope

    … Imaging the small scale structure of the diffuse interstellar medium”

    7.12.16

    Media contact
    Mary Beth Laychak
    Canada-France-Hawaii Telescope
    (808) 885-3121
    mary@cfht.hawaii.edu

    Science contacts
    Marc-Antoine Miville-Deschênes
    IAS (CNRS/Université Paris Sud/Université Paris-Saclay)
    mamd@ias.u-psud.fr
    Tel: 01 69 85 85 79

    Pierre-Alain Duc
    AIM (CEA/CNRS/Université Paris Diderot/Université Paris-Saclay)
    paduc@cea.fr
    Tel:01 69 08 92 68

    1
    Optical images in true colours of the cirrus field obtained with MegaCam on the CFHT. Image credits: MATLAS collaboration, Pierre-Alain Duc.

    CFHT Megacam
    CFHT Megacam

    By combining multi-wavelength data obtained from space with Planck and WISE, and from the ground with MegaCam on the CFHT, a team of researchers has revealed the structure of the diffuse interstellar medium over several square degrees with unprecedented details. In particular, this study reveals the statistical properties of interstellar turbulence over a wide range of scales, from 0.01 to 10 pc.

    ESA/Planck
    ESA/Planck

    NASA/Wise Telescope
    NASA/WISE

    The main innovation of this work is the use of a large optical telescope (the CHFT) to study the structure of the interstellar medium at high resolution and on a large area on the sky, something that is very challenging to obtain with more classical observations done in the infrared. This mapping of these interstellar cirrus clouds located within a few hundred parsec from the Sun can be done because interstellar dust grains scatter starlight. This scattered light has been detected for decades by optical telescopes. Here it is the first time that is exploited scientifically to study the structure of interstellar clouds which is composed of faint filametary structures of various sizes. The result obtained benefit from specific image processing and data acquisition techniques developped in the context of the MATLAS Large Program of the CHFT that aims at detecting faint diffuse emission around galaxies.

    3
    Combined power spectrum : black is Planck radiance, red is WISE and blue is MegaCam. The units of the y axis are arbitrary; each power spectrum was scaled in order to match the others. For each power spectrum, we show data points corresponding to scales larger than the beam and where the power is above the noise component. The data points shown here are noise subtracted and divided by the beam function. The best fit gives P(k) ~ k^(2.9±0.1). Figure from Miville-Deschênes et al. 2016.

    One advantage of the high angular resolution provided by the CFHT data is to eventually reach the angular scale at whcih turbulent energy dissipates. Understanding the exact process by which kinetic energy is dissipated and heat the gas is essential as it is key in the formation of dense structures that lead to the formation of stars. For instance, recent studies based on Herschel observations of molecular clouds have revealed the presence of filaments with width of 0.1 pc that seem constant whatever their mass. This observational fact has been attributed to the energy dissipation process, namely the ambipolar diffusion (friction between neutrals and ions). The present study is showing that the dissipation scale in the interstellar medium is smaller than 0.01 pc which brings important constraints on the exact process resposible for this dissipation.

    These results are emphasizing the fact that scattered light from cirrus, an important source of pollution for deep imaging destined to mapping diffuse structures around massive galaxies, is carrying potentially precious information about the nature of the physical processes involved in the evolution of matter in our own galaxy.

    Science paper:
    Probing interstellar turbulence in cirrus with deep optical imaging: no sign of energy dissipation at 0.01 pc scale

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The CFH observatory hosts a world-class, 3.6 meter optical/infrared telescope. The observatory is located atop the summit of Mauna Kea, a 4200 meter, dormant volcano located on the island of Hawaii. The CFH Telescope became operational in 1979. The mission of CFHT is to provide for its user community a versatile and state-of-the-art astronomical observing facility which is well matched to the scientific goals of that community and which fully exploits the potential of the Mauna Kea site.

    CFHT Telescope
    CFHT Interior
    CFHT

     
  • richardmitnick 2:18 pm on July 11, 2016 Permalink | Reply
    Tags: , , CFHT,   

    From CFHT: “New Distant Dwarf Planet Beyond Neptune” 

    CFHT icon
    Canada France Hawaii Telescope

    7.11.16

    Mary Beth Laychak
    Canada-France-Hawaii Telescope
    (808) 885-3121
    mary@cfht.hawaii.edu

    Thandi Fletcher
    The University of British Columbia
    (604) 822-2234
    thandi.fletcher@ubc.ca

    Science contacts:
    Dr. Michele Bannister
    Postdoctoral Fellow with the Outer Solar System Origins Survey
    Department of Physics and Astronomy
    University of Victoria, Victoria BC
    micheleb@uvic.ca
    tel: +1 250 580 3085

    Dr. Jean-Marc Petit
    Institut UTINAM – UMR CNRS 6213
    Observatoire de Besancon
    41 bis Avenue de l’Observatoire BP 1615
    Jean-Marc.Petit@normalesup.org
    tel: (33) [0]695 207 174

    Dr Ying-Tung (Charles) Chen 陳英同, IAA
    Academia Sinica, Taipei
    ytchen@asiaa.sinica.edu.tw
    tel: +886-2-2366-5356

    1
    Discovery images of RR245. The images show RR245’s slow motion across the sky over three hours (.gif file). Credit OSSOS team.

    An international team of astronomers have discovered a new dwarf planet orbiting in the disk of small icy worlds beyond Neptune. The new object is roughly 700 kilometers in size and has one of the largest orbits for a dwarf planet. Designated 2015 RR245 by the International Astronomical Union’s Minor Planet Center, it was found using the Canada-France-Hawaii Telescope on Maunakea, Hawaii, as part of the ongoing Outer Solar System Origins Survey (OSSOS).

    “The icy worlds beyond Neptune trace how the giant planets formed and then moved out from the Sun. They let us piece together the history of our Solar System. But almost all of these icy worlds are painfully small and faint: it’s really exciting to find one that’s large and bright enough that we can study it in detail.” said Dr Michele Bannister of the University of Victoria in British Columbia, who is a postdoctoral fellow with the Survey.

    National Research Council of Canada’s Dr JJ Kavelaars first sighted RR245 in February 2016 in the OSSOS images from September 2015.”There it was on the screen— this dot of light moving so slowly that it had to be at least twice as far as Neptune from the Sun.” said Bannister.

    The team became even more excited when they realized that the object’s orbit takes it more than 120 times further from the Sun than Earth. The size of RR245 is not yet exactly known, as its surface properties need further measurement. “It’s either small and shiny, or large and dull.” said Bannister.

    2
    Rendering of the orbit of RR245 (orange line). Objects as bright or brighter than RR245 are labeled. The Minor Planet Center describes the object as the 18th largest in the Kuiper Belt. Credit: Alex Parker OSSOS team.

    The vast majority of the dwarf planets like RR245 were destroyed or thrown from the Solar System in the chaos that ensued as the giant planets moved out to their present positions: RR245 is one of the few dwarf planets that has survived to the present day — along with Pluto and Eris, the largest known dwarf planets. RR245 now circles the Sun among the remnant population of tens of thousands of much smaller trans-Neptunian worlds, most of which orbit’s is unseen.

    Worlds that journey far from the Sun have exotic geology with landscapes made of many different frozen materials, as the recent flyby of Pluto by the New Horizons spacecraft showed.

    After hundreds of years further than 12 billion km (80 astronomical units, AU) from the Sun, RR245 is travelling towards its closest approach at 5 billion km (34 AU), which it will reach around 2096. RR245 has been on its highly elliptical orbit for at least the last 100 million years.

    As RR245 has only been observed for one of the seven hundred years it takes to orbit the Sun, where it came from and how its orbit will slowly evolve in the far future is still unknown; its precise orbit will be refined over the coming years, after which RR245 will be given a name. As discoverers, the OSSOS team can submit their preferred name for RR245 to the International Astronomical Union for consideration.

    “OSSOS was designed to map the orbital structure of the outer Solar System to decipher its history.” said Prof. Brett Gladman of the University of British Columbia in Vancouver. “While not designed to efficiently detect dwarf planets, we’re delighted to have found one on such an interesting orbit”.

    RR245 is the largest discovery and the only dwarf planet found by OSSOS, which has discovered more than five hundred new trans-Neptunian objects. “OSSOS is only possible due to the exceptional observing capabilities of the Canada-France-Hawaii Telescope. CFHT is located at one of the best optical observing locations on Earth, is equipped with an enormous wide-field imager, and can quickly adapt its observing each night to new discoveries we make. This facility is truly world leading.” said Gladman.

    Previous surveys have mapped almost all the brighter dwarf planets. 2015 RR245 may be one of the last large worlds beyond Neptune to be found until larger telescopes, such as LSST, come online in the mid 2020s.

    OSSOS involves a collaboration of fifty scientists at institutes and universities from around the world.

    OSSOS is based on observations obtained with MegaPrime/MegaCam, a joint project of the Canada-France-Hawaii Telescope (CFHT) and CEA/DAPNIA, and on data produced and hosted at the Canadian Astronomy Data Centre.

    CFHT is operated by the National Research Council of Canada, the Institute National des Sciences de l’Universe of the Centre National de la Recherche Scientifique of France, and the University of Hawaii, with OSSOS receiving additional access due to contributions from the Institute of Astronomy and Astrophysics, Academia Sinica, Taiwan.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The CFH observatory hosts a world-class, 3.6 meter optical/infrared telescope. The observatory is located atop the summit of Mauna Kea, a 4200 meter, dormant volcano located on the island of Hawaii. The CFH Telescope became operational in 1979. The mission of CFHT is to provide for its user community a versatile and state-of-the-art astronomical observing facility which is well matched to the scientific goals of that community and which fully exploits the potential of the Mauna Kea site.

    CFHT Telescope
    CFHT Interior
    CFHT

     
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