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  • richardmitnick 4:17 pm on January 9, 2015 Permalink | Reply
    Tags: , , , Gemini Observatory   

    From Astronomy- “Galactic herding: new image brings galaxy diversity to life” 

    Astronomy magazine

    Astronomy Magazine

    January 08, 2015
    No Writer Credit
    By Gemini Observatory, Hilo, Hawaii

    A new Gemini image of galaxy group VV 166 provides clarity and definition to the group’s different morphological types.

    Gemini North telescope
    Gemini North Interior
    Gemini North, Mauna Kea, Hawaii

    Galaxy groups are the most evident structures in the nearby universe. They are important laboratories for studying how galaxies form and evolve beyond our Local Group of galaxies, which includes the Milky Way and the Andromeda Galaxy. Exploring the nature of these extragalactic “herds” may help unlock the secrets to the overall structure of the universe.

    l
    Andrew Z. Colvin

    Herd dynamics

    Unlike animal herds, which are generally the same species traveling together, most galaxies move through space in associations composed of myriad types, shapes, and sizes. Galaxy groups differ in their richness, size, and internal structure as well as the ages of their members. Some group galaxies are composed mainly of ancient stars, while others radiate with the power and splendor of youth.

    These facts raise important questions for astronomers: Do all the galaxies in a group share a common origin? Are some just chance alignments? Or do galaxy groups pick up “strays” along the way and amalgamate them into the group?

    Probing galactic group interiors

    The new Gemini image of a grouping called VV 166, named after its position in the catalog by B. Vorontsov-Vel’yaminov, provides clarity and definition to the group’s different morphological types despite its great distance of about 300 million light-years — some 30 times farther away than the closest galaxy groups to our Local Group. One of its most fascinating features is a perfect alignment of three disparate galaxies in a precise equilateral triangle: blue-armed spiral NGC 70 at top, elliptical galaxy NGC 68 to its lower right, and lenticular galaxy NGC 71 to its lower left.

    70
    NGC 70, located in the central NGC 68 group. The galaxies below are NGC 68 (right) and NGC 71 (left)

    The blue spiral (NGC 70) looks like an elephant among lions. This massive galaxy is impressive as it spans 180,000 light-years, or nearly twice the extent of the Milky Way’s reach. Its spiral arms appear blue because they are dominated by active regions of star formation. Here, hot young stars burn with an intense blue light that overpowers that from any older red and yellow stars that might populate the galaxy.

    The opposite is true in the galaxy’s central bulge, where the extinction of star formation has left it to glow with the warm light of ancient red giant and supergiant suns. The galaxy’s sharp starlike core is a telltale sign of an active galactic nucleus powered by a centrally located supermassive black hole feasting on a disk of interstellar gas only a few light-days across.

    In contrast, NGC 68 (lower right) is a much older system known as an elliptical galaxy. NGC 68 is about half the size of the blue spiral and hosts little dust and gas, so star formation is all but absent, as is any spiral structure; the galaxy’s overall yellowish hue reveals that most of its stars are old and red. If there’s an outlier in the image, it might be NGC 68, given that it is about 20 million light-years closer to us than NGC 70. In fact, some researchers have argued that NGC 68 is nothing but a chance alignment. Indeed, while small galaxy groups prevail in the nearby universe, many may not be real gravitationally bound systems at all. But this does not appear to be the case with VV 166, for most of these galaxies are indeed bound as a group.

    Although NGC 71 looks much like NGC 68 — a smooth featureless glow, below and to the left of NGC 68 — it is actually a lens-shaped galaxy seen face on, so it appears more like a sphere. Lenticular galaxies are mysterious creatures, as they appear to be trapped between classifications: like a spiral galaxy, it has a bulge and a disk but no spiral arms; like an elliptical galaxy, it is largely devoid of dust and gas. Possibly galaxies like NGC 71 were originally spiral systems and have either consumed or somehow lost their interstellar material through other galactic interactions.

    The image also shows possible evidence for such a dynamic interaction. Careful inspection reveals that blue spiral’s arms appear distorted between NGC 68 and NGC 71, indicating a possible tidal interaction with one or more of the galaxies. These graceful interactions are choreographed as the group whizzes collectively through space at about 4,000 miles (6,500 kilometers) per second. The image also sharply resolves a flurry of starlight around the elliptical and lenticular systems. Often the brightest cluster galaxy has an extraordinarily diffuse and extended outer halo.

    Just beyond the triangle to the lower left is the group’s fourth-brightest member, a barred spiral galaxy known as NGC 72. Its prominent bar slices across its nucleus. Dusty arms wind out from either end of the bar and form a distinct nuclear ring — the result of recent star formation. Our Milky Way Galaxy has a similar bar component spanning nearly 30,000 light-years from end to end, as well as a circumnuclear ring. But we have evidence that our Milky Way is a “grand-design” spiral with more splendid and numerous arms.

    Despite the apparent diversity of galaxy types in VV 166, the relative proportions of morphologies that we see here may provide a representative sample of galactic types found throughout the universe. It’s possible that some members of VV 166 may have grown by drawing in smaller galaxies from the local environment and consuming them. Or, perhaps, like some herds of animals, galaxy groups may be joined by other “species” — sometimes passively, sometimes violently; this would help to explain the observed mix of morphological types in these groups.

    On the larger cosmological scale, galaxy groups are like beads in the long filamentary structures that make up the skeleton of our universe. These filaments are made up of isolated galaxies, groups, clusters, and superclusters. In time, the isolated galaxies may merge with the groups, which will themselves merge with other groups to form larger clusters of galaxies. As with the animal kingdom, the universe has its hierarchy and includes all things great, and even greater.

    See the full article here.

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  • richardmitnick 4:52 pm on January 8, 2015 Permalink | Reply
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    From Gemini Observatory: “THE GEMINI PLANET IMAGER PRODUCES STUNNING OBSERVATIONS IN ITS FIRST YEAR” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    January 6, 2015
    Media Contacts:

    Peter Michaud
    Public Information and Outreach Manager
    Gemini Observatory, Hilo, HI
    Email: pmichaud”at”gemini.edu
    Cell: (808) 936-6643
    Desk: (808) 974-2510

    Science Contacts:

    Marshall Perrin
    STScI
    Email: mperrin”at”stsci.edu
    Phone: (410) 507-5483

    James R. Graham
    University of California Berkeley
    Email: jrg”at”berkeley.edu
    Cell: (510) 926-9820

    Stunning exoplanet images and spectra from the first year of science operations with the Gemini Planet Imager (GPI) were featured today in a press conference at the 225th meeting of the American Astronomical Society (AAS) in Seattle, Washington. The Gemini Planet Imager GPI is an advanced instrument designed to observe the environments close to bright stars to detect and study Jupiter-like exoplanets (planets around other stars) and see protostellar material (disk, rings) that might be lurking next to the star.

    1
    Figure 1. GPI imaging of the planetary system HR 8799 in K band, showing 3 of the 4 planets. (Planet b is outside the field of view shown here, off to the left.) These data were obtained on November 17, 2013 during the first week of operation of GPI and in relatively challenging weather conditions, but with GPI’s advanced adaptive optics system and coronagraph the planets can still be clearly seen and their spectra measured (see Figure 2). Image credit: Christian Marois (NRC Canada), Patrick Ingraham (Stanford University) and the GPI Team.

    2
    Figure 2. GPI spectroscopy of planets c and d in the HR 8799 system. While earlier work showed that the planets have similar overall brightness and colors, these newly-measured spectra show surprisingly large differences. The spectrum of planet d increases smoothly from 1.9-2.2 microns while planet c’s spectrum shows a sharper kink upwards just beyond 2 microns. These new GPI results indicate that these similar-mass and equal-age planets nonetheless have significant differences in atmospheric properties, for in-stance more open spaces between patchy cloud cover on planet c versus uniform cloud cover on planet d, or perhaps differences in atmospheric chemistry. These data are helping refine and improve a new generation of atmospheric models to explain these effects. Image credit: Patrick Ingraham (Stanford University), Mark Marley (NASA Ames), Didier Saumon (Los Alamos National Laboratory) and the GPI Team.

    Marshall Perrin (Space Telescope Science Institute), one of the instrument’s team leaders, presented a pair of recent and promising results at the press conference. He revealed some of the most detailed images and spectra ever of the multiple planet system HR 8799. His presentation also included never-seen details in the dusty ring of the young star HR 4796A. “GPI’s advanced imaging capabilities have delivered exquisite images and data,” said Perrin. “These improved views are helping us piece together what’s going on around these stars, yet also posing many new questions.”

    The GPI spectra obtained for two of the planetary members of the HR 8799 system presents a challenge for astronomers. GPI team member Patrick Ingraham (Stanford University), lead the paper on HR 8799. Ingraham reports that the shape of the spectra for the two planets differ more profoundly than expected based on their similar colors, indicating significant differences between the companions. “Current atmospheric models of exoplanets cannot fully explain the subtle differences in color that GPI has revealed. We infer that it may be differences in the coverage of the clouds or their composition.” Ingraham adds, “The fact that GPI was able to extract new knowledge from these planets on the first commissioning run in such a short amount of time, and in conditions that it was not even designed to work, is a real testament to how revolutionary GPI will be to the field of exoplanets.”

    Perrin, who is working to understand the dusty ring around the young star HR 4796A, said that the new GPI data present an unprecedented level of detail in studies of the ring’s polarized light. “GPI not only sees the disk more clearly than previous instruments, it can also measure how polarized its light appears, which has proven crucial in under-standing its physical properties.” Specifically, the GPI measurements of the ring show it must be partially opaque, implying it is far denser and more tightly compressed than similar dust found in the outskirts of our own Solar System, which is more diffuse. The ring circling HR 4796A is about twice the diameter of the planetary orbits in our Solar System and its star about twice our Sun’s mass. “These data taken during GPI commissioning show how exquisitely well its polarization mode works for studying disks. Such observations are critical in advancing our understanding of all types and sizes of planetary systems – and ultimately how unique our own solar system might be,” said Perrin.

    3
    Figure 3. GPI imaging polarimetry of the circumstellar disk around HR 4796A, a ring of dust and planetesimals similar in some ways to a scaled up version of the solar system’s Kuiper Belt.

    Kuiper Belt
    Kuiper Belt, for illustration of the discussion

    These GPI observations reveal a complex pattern of variations in brightness and polarization around the HR 4796A disk. The western side (tilted closer to the Earth) appears brighter in polarized light, while in total intensity the eastern side appears slightly brighter, particularly just to the east of the widest apparent separation points of the disk. Reconciling this complex and apparently-contradictory pattern of brighter and darker regions required a major overhaul of our understanding of this circumstellar disk. Image credit: Marshall Perrin (Space Telescope Science Institute), Gaspard Duchene (UC Berkeley), Max Millar-Blanchaer (University of Toronto), and the GPI Team.

    4
    Figure 4. Diagram depicting the GPI team’s revised model for the orientation and composition of the HR 4796A ring. To explain the observed polarization levels, the disk must consist of relatively large (> 5 µm) silicate dust particles, which scatter light most strongly and polarize it more for forward scattering. To explain the relative faintness of the east side in total intensity, the disk must be dense enough to be slightly opaque, comparable to Saturn’s optically thick rings, such that on the near side of the disk our view of its brightly illuminated inner portion is partially obscured. This revised model requires the disk to be much narrower and flatter than expected, and poses a new challenge for theories of disk dynamics to explain. GPI’s high contrast imaging and polarimetry capabilities together were essential for this new synthesis. Image credit: Marshall Perrin (Space Telescope Science Institute).

    During the commissioning phase, the GPI team observed a variety of targets, ranging from asteroids in our solar system, to an old star near its death. Other teams of scientists have been using GPI as well and already astronomers around the world have published eight papers in peer-reviewed journals using GPI data. “This might be the most productive new instrument Gemini has ever had,” said Professor James Graham of the University of California, who leads the GPI science team and who will describe the GPI exoplanet survey in a talk scheduled at the AAS meeting on Thursday, January 8th.

    The Gemini Observatory staff integrated the complex instrument into the telescope’s software and helped to characterize GPI’s performance. “Even though it’s so complicated, GPI now operates almost automatically,” said Gemini’s instrument scientist for GPI Fredrik Rantakyro. “This allows us to start routine science operations.” The instrument is now available to astronomers and their proposals are scheduled to start ob-serving in early 2015. In addition, “shared risk” observations are already underway, starting in November 2014.

    The one thing GPI hasn’t done yet is discovered a new planet. “For the early tests, we concentrated on known planets or disks” said GPI PI Bruce Macintosh. Now that GPI is fully operational, the search for new planets has begun. In addition to observations by astronomers world-wide, the Gemini Planet Imager Exoplanet Survey (GPIES) will look at 600 carefully selected stars over the next few years. GPI ‘sees’ planets through the infrared light they emit when they’re young, so the GPIES team has assembled a list of the youngest and closest stars. So far the team has observed 50 stars, and analysis of the data is ongoing. Discovering a planet requires confirmation observations to distinguish a true planet orbiting the target star from a distant star that happens to sneak into GPI’s field of view – a process that could take years with previous instruments. The GPIES team found one such object in their first survey run, but GPI observations were sensitive enough to almost immediately rule it out. Macintosh said, “With GPI, we can tell almost instantly that something isn’t a planet – rather than months of uncertainty, we can get over our disappointment almost immediately. Now it’s time to find some real planets!”

    About GPI/GPIES

    The Gemini Planet Imager (GPI) instrument was constructed by an international collaboration led by Lawrence Livermore National Laboratory under Gemini’s supervision. The GPI Exoplanet Survey (GPIES) is the core science program to be carried out with it. GPIES is led by Bruce Macintosh, now a professor at Stanford University and James Graham, professor at the University of California at Berkeley and is designed to find young, Jupiter-like exoplanets. They survey will observe 600 young nearby stars in 890 hours over three years. Targets have been carefully selected by team members at Arizona State University, the University of Georgia, and UCLA. The core of the data processing architecture is led by Marshall Perrin of the Space Telescope Science Institute, with the core software originally written by University of Montreal, data management infrastructure from UC Berkeley and Cornell University, and contributions from all the other team institutions. The SETI institute located in California manages GPIES’s communications and public out-reach. Several teams located at the Dunlap Institute, the University of Western Ontario, the University of Chicago, the Lowell Observatory, NASA Ames, the American Museum of Natural History, University of Arizona and the University of California at San Diego and at Santa Cruz also contribute to the survey. The GPI Exoplanet Survey is supported by the NASA Origins Program NNX14AG80, the NSF AAG pro-gram, and grants from other institutions including the University of California Office of the President. Dropbox Inc. has generously provided storage space for the entire survey’s archive.

    See the full article here.

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    Gemini North
    Gemini North, Hawai’i

    Gemini South
    Gemini South, Chile
    AURA Icon

    The Gemini Observatory consists of twin 8.1-meter diameter optical/infrared telescopes located on two of the best observing sites on the planet. From their locations on mountains in Hawai‘i and Chile, Gemini Observatory’s telescopes can collectively access the entire sky.
    Gemini was built and is operated by a partnership of six countries including the United States, Canada, Chile, Australia, Brazil and Argentina. Any astronomer in these countries can apply for time on Gemini, which is allocated in proportion to each partner’s financial stake.

     
  • richardmitnick 4:25 pm on December 15, 2014 Permalink | Reply
    Tags: , , , , Gemini Observatory   

    From Gemini: “Good data from the last GeMS Run” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    11 Dec 2014
    M Paredes

    f

    An image of the the very young star form region N159W recently obtained with GeMS. Credit: Anais Bernard (Laboratoire d’Astrophysique de Marseille, LAM), Benoit Neichel (LAM).

    Gemini GeMS
    GeMS

    Successful Multi-conjugate Adaptive Optics Run at Gemini South

    The Gemini Multi-conjugate adaptive optics System (GeMS) at Gemini South has completed a successful run of 9 nights, with several programs executed and two completed. According to the AO* science fellow Vincent Garrel the performance of the system was, “among the best performances we’ve ever achieved.”

    Rodrigo Carrasco, associate astronomer at Gemini, reports that “During the nights of my shift, we obtained data with 70-80 milliarcsecond (mas) resolution. This is really good!”

    Classical (visiting) observers, Sarah Sweet (from the Australian National University) and Benoit Neichel also report obtaining a significant amount of data, with resolutions between 70 to 100 mas (see image with this post).

    Next Challenges…

    The GeMS team is now actively preparing for the next big hardware upgrade called the Natural Guide Star New Generation Sensor (NGS2) program, which is been building by the Australian National University. Watch for updates here and on the Gemini website.

    Also, a faulty detector, which is on one of the tip&tilt wavefront sensors, will be replaced – this has produced regular time loss. This repair should be ready for operations by the next GeMS run in January 2015.

    Watch for more details in early 2015 on continued progress with Gemini’s powerful adaptive optics capabilities.

    *Adaptive Optics

    See the full article here.

    Please help promote STEM in your local schools.

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    Gemini North
    Gemini North, Hawai’i

    Gemini South
    Gemini South, Chile
    AURA Icon

    The Gemini Observatory consists of twin 8.1-meter diameter optical/infrared telescopes located on two of the best observing sites on the planet. From their locations on mountains in Hawai‘i and Chile, Gemini Observatory’s telescopes can collectively access the entire sky.
    Gemini was built and is operated by a partnership of six countries including the United States, Canada, Chile, Australia, Brazil and Argentina. Any astronomer in these countries can apply for time on Gemini, which is allocated in proportion to each partner’s financial stake.

     
  • richardmitnick 3:55 pm on August 5, 2014 Permalink | Reply
    Tags: , , , , Gemini Observatory,   

    From Carnegie Institution for Science via Gemini Observatory: “Planet-like Object May Have Spent Its Youth as Hot as a Star” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    August 5, 2014
    No Writer Credit

    Astronomers have discovered an extremely cool object that could have a particularly diverse history—although it is now as cool as a planet, it may have spent much of its youth as hot as a star.

    four
    A four-stage sequence (left to right) showing the possible extreme temperature evolution for WISE J0304-2705. For about 20 million years, the object was as hot as a star, shining with a temperature of at least 5,100 degrees Fahrenheit (2800 degrees Celsius). After about 100 million years it had cooled to about 2,700 degrees Fahrenheit (1500 degrees Celsius), and by a billion years its temperature was about 1,800 degrees Fahrenheit (1000 degrees Celsius). The final stage is billions of years later, when WISE J0304-2705 has cooled to its current planetary temperature of 100-150 C. Artwork credit: John Pinfield

    The current temperature of the object is 200 to 300 degrees Fahrenheit (100 to 150 degrees Celsius), which is intermediate between that of the Earth and of Venus. However, the object shows evidence of a possible ancient origin, implying that a large change in temperature has taken place. In the past this object would have been as hot as a star for many millions of years.

    Called WISE J0304-2705, the object is a member of the recently established “Y dwarf” class—the coolest stellar temperature class yet defined, following the other classes O, B, A, F, G, K, M, L, and T. Although the temperature is similar to that of the planets, the object is dissimilar to the rocky Earth-like planets, and instead is a giant ball of gas like Jupiter.

    The international discovery team, led by David Pinfield from the University of Hertfordshire and including Carnegie’s Yuri Beletsky, identified the Y dwarf using the WISE observatory—a NASA space telescope that has imaged the entire sky in the mid-infrared. The team also measured the spectrum of light emitted by the Y dwarf, which allowed them to determine its current temperature and better understand its history. Their work is published by Monthly Notices of the Royal Astronomical Society.

    NASA Wise Telescope
    NASA/Wise

    Only 20 other Y dwarfs have been discovered to-date, and amongst these WISE J0304-2705 is defined as “peculiar” due to unusual features in its emitted light spectrum.

    “Our measurements suggest that this Y dwarf may have a composition and/or age characteristic of one of the Galaxy’s older members,” Pinfield explained. “This would mean its temperature evolution could have been rather extreme.”

    The reason that WISE J0304-2705 undergoes such extensive evolutionary cooling is because it is “sub-stellar,” meaning its interior never gets hot enough for hydrogen fusion, the process that has kept our Sun hot for billions of years, and without an energy source maintaining a stable temperature, cooling and fading is inevitable.

    If WISE J0304-2705 is an ancient object, then its temperature evolution would have followed through an understood series of stages: During its first approximately 20 million years it would have a temperature of at least 5,100 degrees Fahrenheit (2800 degrees Celsius), the same as red dwarf stars like Proxima Centauri (the nearest star to the Sun). After 100 million years it would have cooled to about 2,700 degrees Fahrenheit (1,500 degrees Celsius), with silicate clouds condensing out in its atmosphere. At a billion years of age it would have cooled to about 1,800 degrees Fahrenheit (1,000 degrees Celsius), so cool that methane gas and water vapor would dominate its appearance. And since then it would have continued to cool to its current temperature, barely enough to boil water for a cup of tea.

    WISE J0304-2705 is as massive as 20-30 Jupiters combined, which is intermediate between the more massive stars and typical planets. But in terms of temperature it may have actually “taken the journey” from star-like to planet-like conditions.

    Having identified WISE 0304-2705, Pinfield’s team made crucial ground-based observations with some of the world’s largest telescopes—the 8-meter Gemini South Telescope, the 6.5-meter Magellan Telescope and the European Southern Observatory’s 3.6-meter New Technology Telescope, all located in the Chilean Andes.

    Gemini South telescope
    Gemini South

    Magellan 6.5 meter telescopes
    Magellan

    ESO NTT
    ESO/NTT

    Team member Mariusz Gromadzki said: “The ground based measurements were very challenging, even with the largest telescopes. It was exciting when the results showed just how cool this object was, and that it was unusual”.

    “The discovery of WISE J0304-2705, with its peculiar light spectrum, poses ongoing challenges for the most powerful modern telescopes that are being used for its detailed study” remarked Maria Teresa Ruiz, team member from the Universidad de Chile.

    WISE J0304-2705 is located in the Fornax (Furnace) constellation, belying its cool temperature.

    There is currently no lower limit for Y dwarf temperatures, and there could be many even cooler and more diverse objects un-detected in the solar neighborhood. WISE went into hibernation in February 2011 after carrying out its main survey mission. However, by popular demand it was revived in December 2013, and is continuing to observe as part of a three-year mission extension [Neowise].

    “WISE gives us wonderful sensitivity to the coolest objects” said Pinfield, “and with three more years of observations we will be able to search the sky for more Y dwarfs, and more diverse Y dwarfs.”

    The paper, to be published by Monthly Notices of the Royal Astronomical Society, is available on astro-ph

    See the full article here.

    Gemini North
    Gemini North, Hawai’i

    Gemini South
    Gemini South, Chile
    AURA Icon

    The Gemini Observatory consists of twin 8.1-meter diameter optical/infrared telescopes located on two of the best observing sites on the planet. From their locations on mountains in Hawai‘i and Chile, Gemini Observatory’s telescopes can collectively access the entire sky.
    Gemini was built and is operated by a partnership of six countries including the United States, Canada, Chile, Australia, Brazil and Argentina. Any astronomer in these countries can apply for time on Gemini, which is allocated in proportion to each partner’s financial stake.

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  • richardmitnick 9:23 am on July 10, 2014 Permalink | Reply
    Tags: , , , , Gemini Observatory   

    From Fermilab- “The sky is not the limit: DES gets time on Gemini telescope” 


    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    Thursday, July 10, 2014
    Hanae Armitage

    In an ambitious five-year mission, the Dark Energy Survey team has devoted itself to mapping the southern sky in unprecedented detail, ultimately hoping to decipher what may stand as the most bewildering phenomenon of our expanding universe.

    In March, DES applied to the Large and Long Program at the Gemini Observatory, a program meant to foster scientific exploration through global collaboration. Although the Gemini Observatory has existed since 2000, the Large and Long Program launched just last year as another means to probe the shrapnel of the big bang. It offers time on two of the world’s finest telescopes, one located atop an 8,900-foot mountain in the Chilean Andes (Gemini South) and the other on Mauna Kea, Hawaii (Gemini North).

    Gemini North telescope
    Gemini North

    Gemini South telescope
    Gemini South

    Just last month, co-leader of the Strong Lensing Science Working Group at DES, Liz Buckley-Geer, received the email she’d been waiting for: Spread over the next three years, DES had been awarded a lofty total of 276 hours on Gemini South.

    “Because we were asking for such a big block of time I really didn’t think we had much of a chance,” Buckley-Geer said. “I was pretty gobsmacked when I got the email two weeks ago.”

    With a hefty 8.1-meter mirror, the Gemini telescope is twice as large as the telescope on which DECam is currently mounted. But DES scientists don’t plan to take new images with Gemini South. DECam images are plenty clear and show high-quality snapshots of galaxies and galaxy clusters. Instead of imaging, DES scientists will use an instrument called a spectrograph to further inspect the images and, in some cases, confirm a rare phenomenon called strong lensing.

    DECam
    DECam

    One of five methods DES uses to explore dark energy, strong lensing is the bending of light from a distant galaxy, or source, due to the gravitational influence of a massive foreground object, or lens. Lensing changes the observed shape of the distant galaxy and intensifies brightness. To find these strong lensing systems in the DECam images, DES scientists look for objects that look distorted, often appearing as long bright arcs, multiple blue knots or, in the rarest cases, an Einstein ring. DES will focus on certain classes of strong lenses that can be used to study dark energy.

    “The strong lenses provide a kind of peephole to the more distant, fainter universe that wouldn’t be available if the lenses weren’t there,” said DES Operations Scientist Tom Diehl.

    But what appear to be strong lenses are not always so. To separate the lenses from the impostors, scientists measure the redshifts of both the lens and the source. A true strong lens is one in which the source redshift is larger than the lens redshift.

    A redshift occurs when light wavelengths increase, or shift toward the red side of the electromagnetic spectrum. The measured redshift of a galaxy is related to the expansion of the universe as a function of time, and it allows DES scientists to calculate the distance to the object.

    To determine the redshift of a galaxy, the scientists will compare the spectrum of the obtained light with known features in the spectrum of various chemical compounds found on Earth. If the same features are seen in an observed spectrum from a distant source but occur at shifted wavelengths, then the redshift can be calculated.

    “The observations with Gemini will give us the redshifts of all these objects, and armed with that information we can move on to the next step,” Buckley-Geer said. “It’s not all the information we need, but it’s one piece of the jigsaw puzzle closer to understanding these system in relation to dark energy.”

    See the full article here.

    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics.


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  • richardmitnick 4:12 pm on May 20, 2014 Permalink | Reply
    Tags: , , , , Gemini Observatory,   

    From Gemini Observatory: “Tour of the Telescope” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    gpi

    May 15, 2014
    Jason Wang

    Yesterday, we had a chance to see the telescope in all of its glory. And it is HUGE!

    scope
    The Gemini South Telescope with the dome lights on.

    It really makes you appreciate the amount of equipment you need to directly image these faint extrasolar planets that are orbiting other stars. Andrew, the telescope operator, then pointed the telescope down so that we could get some nice photographs with the 8-meter mirror. Here’s my telescope selfie:

    j
    Telescope selfie!

    The 8 meter mirror is so big it’s hard to fit into one single shot. This was the best I could do. Although some others are a bit more serious about their photography…

    men
    Markus sprawling out to get a nice shot of Lee, a journalist visiting us, with the telescope.

    Before the sun fully set, I ran outside to grab this image of the telescope dome open.

    g2
    The telescope dome open at sunset .

    Now back to observing!

    About Jason Wang
    Jason is a graduate student at the University of California, Berkeley. He is currently working with Professor James Graham on the Gemini Planet Imager (GPI). He works on GPI astrometry, the image reduction pipeline, and high contrast imaging techniques.

    See the full article here.

    Gemini North
    Gemini North, Hawai’i

    Gemini South
    Gemini South, Chile
    AURA Icon

    The Gemini Observatory consists of twin 8.1-meter diameter optical/infrared telescopes located on two of the best observing sites on the planet. From their locations on mountains in Hawai‘i and Chile, Gemini Observatory’s telescopes can collectively access the entire sky.
    Gemini was built and is operated by a partnership of six countries including the United States, Canada, Chile, Australia, Brazil and Argentina. Any astronomer in these countries can apply for time on Gemini, which is allocated in proportion to each partner’s financial stake.


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  • richardmitnick 6:13 am on May 15, 2014 Permalink | Reply
    Tags: , , , , Gemini Observatory   

    From Gemini Observatory: “Odd planet, so far from its star… “ 

    NOAO

    Gemini Observatory
    Gemini Observatory

    Science Contacts:

    Marie-Ève Naud
    CRAQ – Université de Montréal
    514 343-6111, ext 3797
    naud “at” astro.umontreal.ca

    René Doyon
    Director, Observatoire du Mont-Mégantic
    Professor, Department of Physics
    CRAQ – Université de Montréal
    514 343-6111, ext 3204
    doyon “at” astro.umontreal.ca

    Media Contacts:

    Olivier Hernandez, Ph. D.
    CRAQ – Université de Montréal / Head of Media Relations
    olivier “at” astro.umontreal.ca
    514 343-6111, ext 4681

    Peter Michaud
    Gemini Observatory Public Information and Outreach Office
    Hilo, Hawai‘i
    pmichaud “at” gemini.edu
    Desk: (808) 974-2510
    Cell: (808) 936-6643

    An international team led by Université de Montréal researchers has discovered and photographed a new planet 155 light years from our solar system.

    A gas giant has been added to the short list of exoplanets discovered through direct imaging. It is located around GU Psc, a star three times less massive than the Sun and located in the constellation Pisces. The international research team, led by Marie-Ève Naud, a PhD student in the Department of Physics at the Université de Montréal, was able to find this planet by combining observations from the Gemini Observatory, the Observatoire Mont-Mégantic (OMM), the Canada-France-Hawaii Telescope (CFHT) and the W.M. Keck Observatory.

    Canada-France-Hawaii Telescope
    Canada-France-Hawaii

    Keck Observatory
    Keck on Mauna Kea in Hawaii

    A distant planet that can be studied in detail

    GU Psc b is around 2,000 times the Earth-Sun distance from its star, a record among exoplanets. Given this distance, it takes approximately 80,000 Earth years for GU Psc b to make a complete orbit around its star! The researchers also took advantage of the large distance between the planet and its star to obtain images. By comparing images obtained in different wavelengths (colours) from the OMM and CFHT, they were able to correctly detect the planet.

    “Planets are much brighter when viewed in infrared rather than visible light, because their surface temperature is lower compared to other stars,” says Naud. “This allowed us to indentify GU Psc b.”

    Knowing where to look

    The researchers were looking around GU Psc because the star had just been identified as a member of the young star group AB Doradus. Young stars (only 100 million years old) are prime targets for planetary detection through imaging because the planets around them are still cooling and are therefore brighter. This does not mean that planets similar to GU Psc b exist in large numbers, as noted by by Étiene Artigau, co-supervisor of Naud’s thesis and astrophysicist at the Université de Montréal. “We observed more than 90 stars and found only one planet, so this is truly an astronomical oddity!”

    Observing a planet does not directly allow determining its mass. Instead, researchers use theoretical models of planetary evolution to determine its characteristics. The light spectrum of GU Psc b obtained from the Gemini North Telescope in Hawaii was compared to such models to show that it has a temperature of around 800°C. Knowing the age of GU Psc due to its location in AB Doradus, the team was able to determine its mass, which is 9-13 times that of Jupiter.

    Gemini North telescope
    Gemini North, Mauna Kea Hawaii

    In the coming years, the astrophysicists hope to detect planets that are similar to GU Psc but much closer to their stars, thanks, among other things, to new instruments such as the GPI (Gemini Planet Imager) recently installed on the Gemini South telescope in Chile. The proximity of these planets to their stars will make them much more difficult to observe. GU Psc b is therefore a model for better understanding these objects.

    Gemini South telescope
    Gemini South, Cerro Pachón, Chile

    “GU Psc b is a true gift of nature. The large distance that separates it from its star allows it to be studied in depth with a variety of instruments, which will provide a better understanding of giant exoplanets in general,” says René Doyon, co-supervisor of Naud’s thesis and OMM Director.

    The team has started a project to observe several hundred stars and detect planets lighter than GU Psc b with similar orbits. The discovery of GU Psc, a rare object indeed, raises awareness of the significant distance that can exist between planets and their stars, opening the possibility of searching for planets with powerful infrared cameras using much smaller telescopes such at the one at the Observatoire du Mont-Mégantic. The researchers also hope to learn more about the abundance of such objects in the next few years, in particular, using the Gemini Planet Imager, the CFHT’s SPIRou, and the James Webb Space Telescope’s FGS/NIRISS.

    About the study

    The article Discovery of a Wide Planetary-Mass Companion to the Young M3 Star GU Psc will be published in The Astrophysical Journal on May 20, 2014. The team, led by Marie-Ève Naud, doctoral student at the Department of Physics of the Université de Montréal and member of the CRAQ, consisted mainly of UdeM students and researchers, including Étienne Artigau, Lison Malo, Loïc Albert, René Doyon, David Lafrenière, Jonathan Gagné, and Anne Boucher. Collaborators from other institutions also participated, including Didier Saumon, Los Alamos National Laboratory, New Mexico; Caroline Morley, UC Santa Cruz, California; France Allard and Derek Homeier, Centre for Astrophysical Research, Lyon, France; and Christopher Gelino and Charles Beichman, Caltech, California. The study was made possible with funding from the Fonds de recherche du Québec – Nature et technologies and the Natural Sciences and Engineering Research Council of Canada.

    See the full article here.

    Gemini North
    Gemini North, Hawai’i

    Gemini South
    Gemini South, Chile
    AURA Icon

    The Gemini Observatory consists of twin 8.1-meter diameter optical/infrared telescopes located on two of the best observing sites on the planet. From their locations on mountains in Hawai‘i and Chile, Gemini Observatory’s telescopes can collectively access the entire sky.
    Gemini was built and is operated by a partnership of six countries including the United States, Canada, Chile, Australia, Brazil and Argentina. Any astronomer in these countries can apply for time on Gemini, which is allocated in proportion to each partner’s financial stake.


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  • richardmitnick 8:39 am on April 7, 2014 Permalink | Reply
    Tags: , , , , Gemini Observatory,   

    From SETI Institute: “The orbit of the exoplanet Beta Pictoris b – The first peer-reviewed article with GPI” 


    No Date

    Franck Marchis, Researcher at the Carl Sagan Center of the SETI Institute since July 2007

    Following our very successful first light observing runs in late 2013, the first publication based on Gemini Planet Imager observations is now complete! It has been accepted for publication in the Proceedings of the National Academy of Sciences as part of a special issue on exoplanets, and is now available on Astro-ph. We report in this publication the performance of the Gemini Planet Imager based on the first light tests. The first scientific result demonstrates that right from the start, GPI has been performing well enough to yield new insights into exoplanets: Our astrometric observations from November 2013 gave us important new information on the orbit of the planet Beta Pictoris b.

    bp
    An annotated view of the Beta Pictoris system.

    NOAO Gemini Planet Imager
    Gemini Planet Imager

    Beta Pictoris b is a young planet orbiting the bright star Beta Pictoris located 63 light-year away from us. This young star is known for its debris disk which was the first one ever imaged. In 2010, direct imaging observations revealed the presence of a planet embedded in the disk.

    Only 12 million years old, or less than three-thousandths of the age of the Sun, Beta Pictoris is 75% more massive than our parent star. It is located about 60 light-years away towards the constellation of Pictor (the Painter) and is one of the best-known examples of a star surrounded by a dusty debris disk (Credit: ESO)

    With a declination of -51 deg and a magnitude in visible of 3.9 ( visible with unaided eye), Beta Pictoris was the perfect target to test our “brand new” adaptive optics system on November 18. The planet was observed in H-band, at roughly ~1.65 micron (in the near-infrared) and obtained 22 individual 60-second images in coronagraphic mode.

    The on-site observers reported with amazement that they were able to see the planet in a single, raw, 60-s exposure frame. This illustrated the great potential of our instrument to detect exoplanets, since with previous instrument the planet was only visible after roughly 1h of observation.

    The figure below shows the resulting image after applying the TLOCI algorithm. The planet in orbit around Beta Pictoris is detected with a signal-to-noise ratio of ~100.

    image

    The observations of GPI revealed a motion of the planet with respect to previous observations collected with previous AO systems on 6-8m class telescopes such as VLT/NACO, Gemini/NICI and the Magellan AO system. After gathering all those astrometric positions, and adding our point, we found out that the planet orbits at ~9 AU from its star with a period of ~20.5 years.

    The orbit is in agreement with previous orbit estimates but this additional point improved its accuracy significantly. First this work showed that the planet has recently turned around on its orbit. Secondly, it confirmed that the planet orbits in the same plane as the disk. Finally, the refined orbital parameters allowed to predict with a few percent confidence that the planet might transit its star in September through December 2017. It is possible that a similar transit of the planet across the star was observed in 1981.

    This work suggests that GPI, and other Extreme AO instruments with high contrast imaging, are about to open a new era in planetary system characterizations.

    Clear skies,

    Franck M.

    See the full article here.

    SETI Institute – 189 Bernardo Ave., Suite 100
    Mountain View, CA 94043
    Phone 650.961.6633 – Fax 650-961-7099
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  • richardmitnick 8:14 am on April 7, 2014 Permalink | Reply
    Tags: , , , , Gemini Observatory   

    From SETI Institute: “World’s Most Powerful Planet Finder Turns its Eye to the Sky – Gemini Planet Imager Obtains First Light Images -“ 

    Tuesday, January 07 2014

    Karen Randall
    SETI Institute
    Email: krandall@seti.org
    Desk: (650) 960-4537

    Peter Michaud
    Gemini Observatory, Hilo, HI
    Email: pmichaud@gemini.edu
    Cell: (808) 936-6643
    Desk: (808) 974-2510

    Science Contacts:

    Bruce Macintosh
    Lawrence Livermore National Laboratory
    Email: macintosh1@llnl.gov
    Cell: 650-793-0969
    Desk: (650) 725-4116

    James Graham
    University of California
    Email: jrg@berkeley.edu

    Franck Marchis
    SETI Institute
    Email: fmarchis@seti.org
    Cell: (510) 599-0604

    After nearly a decade of development, construction, and testing, the world’s most advanced instrument for directly imaging and analyzing planets around other stars is pointing skyward and collecting light from distant worlds.

    The instrument, called the Gemini Planet Imager (GPI), was designed, built, and optimized for imaging faint planets next to bright stars and probing their atmospheres, and studying dusty disks around young stars. It is the most advanced such instrument to be deployed on one of the world’s biggest telescopes – the 8-meter Gemini South telescope in Chile.

    NOAO Gemini South
    Gemini South

    NOAO Gemini Planet Imager
    GPI

    “Even these early first-light images are almost a factor of 10 better than the previous generation of instruments. In one minute, we are seeing planets that used to take us an hour to detect,” says Bruce Macintosh of the Lawrence Livermore National Laboratory who led the team that built the instrument.

    GPI detects infrared (heat) radiation from young Jupiter-like planets in wide orbits around other stars, those equivalent to the giant planets in our own Solar System not long after their formation. Every planet GPI sees can be studied in detail.

    “Most planets that we know about to date are only known because of indirect methods that tell us a planet is there, a bit about its orbit and mass, but not much else,” says Macintosh. “With GPI we directly image planets around stars – it’s a bit like being able to dissect the system and really dive into the planet’s atmospheric makeup and characteristics.”

    GPI carried out its first observations last November – during an extremely trouble-free debut for an extraordinarily complex astronomical instrument the size of a small car. “This was one of the smoothest first-light runs Gemini has ever seen” says Stephen Goodsell, who manages the project for the observatory.

    For GPI’s first observations, the team targeted previously known planetary systems, including the well-known Beta Pictoris system; in it GPI obtained the first-ever spectrum of the very young planet Beta Pictoris b. The first-light team also used the instrument’s polarization mode – which can detect starlight scattered by tiny particles – to study a faint ring of dust orbiting the very young star HR4796. With previous instruments, only the ends of this dust ring, (which may be the debris remaining from planet formation), could be seen, but with GPI astronomers can follow the entire circumference of the ring. The group also observed the system of planets orbiting HR8799.

    Although GPI was designed to look at distant planets, it can also observe objects in our Solar System. The accompanying test images of Jupiter’s moon Europa, for example, can allow scientists to map changes in the satellite’s surface composition. The images were released today at the 223rd meeting of the American Astronomical Society in Washington DC.

    europa
    (Above) Comparison of Europa observed with Gemini Planet Imager in K1 band on the right and visible albedo visualization based on a composite map made from Galileo SSI and Voyager 1 and 2 data (from USGS) on the left. While GPI is not designed for ‘extended’ objects like this, its observations could help in following surface alterations on icy satellites of Jupiter or atmospheric phenomena (e.g. clouds, haze) on Saturn’s moon Titan. The GPI near-infrared color image is a combination of 3 wavelength channels.Processing by Marshall Perrin, Space Telescope, Science Institute and Franck Marchis, SETI Institute

    “Seeing a planet close to a star after just one minute, was a thrill, and we saw this on only the first week after the instrument was put on the telescope!” says Fredrik Rantakyro a Gemini staff scientist working on the instrument. “Imagine what it will be able to do once we tweak and completely tune its performance.”

    Exoplanets are extraordinarily faint and difficult to see next to a bright star,” notes GPI chief scientist Professor James R. Graham of the University of California who has worked with Macintosh on the project since its inception. GPI can see planets a million times fainter than their parent stars. Often described, ‘like trying to see a firefly circling a streetlight thousands of kilometers away,’ instruments used to image exoplanets must be designed and built to “excruciating tolerances,” points out Leslie Saddlemyer of NRC Herzberg (part of the National Research Council of Canada), who served as GPI’s systems engineer. “Each individual mirror inside GPI has to be smooth to within a few times the size of an atom,” Saddlemyer adds.

    “GPI represents an amazing technical achievement for the international team of scientists who conceived, designed, and constructed the instrument, as well as a hallmark of the capabilities of the Gemini telescopes. It is a highly-anticipated and well-deserved step into the limelight for the Observatory”, says Dr. Gary Schmidt, program officer at the National Science Foundation (NSF), which funded the project along with the other countries of the Gemini Observatory partnership.

    “After years of development and simulations and testing, it’s incredibly exciting now to be seeing real images and spectra of exoplanets observed with GPI. It’s just gorgeous data,” says Marshall Perrin of the Space Telescope Science Institute.

    “The entire exoplanet community is excited for GPI to usher in a whole new era of planet finding,” says physicist and exoplanet expert Sara Seager of the Massachusetts Institute of Technology. Seager, who is not affiliated with the project adds, “Each exoplanet detection technique has its heyday. First it was the radial velocity technique (ground-based planet searches that started the whole field). Second it was the transit technique (namely Kepler). Now,” she says, “it is the ‘direct imaging’ planet-finding technique’s turn to make waves.”

    In 2014, the GPI team will begin a large-scale survey, looking at 600 young stars to see what giant planets orbit them. GPI will also be available to the whole Gemini community for other projects, ranging from studies of planet-forming disks to outflows of dust from massive, dying stars.

    Looking through Earth’s turbulent atmosphere, even with advanced adaptive optics, GPI will only be able to see Jupiter-sized planets. But similar technology is being proposed for future space telescopes.

    “Some day, there will be an instrument that will look a lot like GPI, on a telescope in space,” Macintosh projects. “And the images and spectra that will come out of that instrument will show a little blue dot that is another Earth.”

    GPI is an international project led by the Lawrence Livermore National Laboratory (LLNL) under Gemini’s supervision, with Macintosh as Principal Investigator and LLNL engineer David Palmer as project manager. LLNL also produced the advanced adaptive optics system that measures and corrects for atmospheric turbulence a thousand times a second. Scientists at the American Museum of Natural History, led by Ben Oppenheimer, who also led a project demonstrating some of the same technologies used in GPI on the 5-meter Palomar project, designed special masks that are part of the instrument’s coronagraph which blocks the bright starlight that can obscure faint planets. Engineer Kent Wallace and a team from NASA’s Jet Propulsion Laboratory constructed an ultra-precise infrared wavefront sensor to measure small distortions in starlight that might mask a planet. A team at the University of California Los Angeles’ Infrared Laboratory, under the supervision of Professor James Larkin, together with Rene Doyon at the University of Montreal, assembled the infrared spectrograph that dissects the light from planets. Data analysis software written at University of Montreal and the Space Telescope Science Institute assembles the raw spectrograph data into three-dimensional cubes. NRC Herzberg in British Columbia Canada, built the mechanical structure and software that knits all the pieces together. James R. Graham, as project scientist, led the definition of the instrument’s capabilities. The instrument underwent extensive testing in a laboratory at the University of California Santa Cruz before shipping to Chile in August. The SETI institute in California manages GPI’s data and communications.

    See the full article here.

    SETI Institute – 189 Bernardo Ave., Suite 100
    Mountain View, CA 94043
    Phone 650.961.6633 – Fax 650-961-7099
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  • richardmitnick 8:09 pm on April 2, 2014 Permalink | Reply
    Tags: , , , , Gemini Observatory   

    From Gemini Observatory: “Sakurai’s Object: Stellar Evolution in Real Time” 

    NOAO

    Gemini Observatory
    Gemini Observatory

    April 2, 2014
    Joint NOAO/Gemini Observatory Press Release

    Media Contacts:
    Dr. Katy Garmany
    Deputy Press Officer
    National Optical Astronomy Observatory
    950 N Cherry Ave, Tucson AZ 85719 USA
    Email: kgarmany”at”noao.edu
    Desk: +1 520-318-8526

    Peter Michaud
    Pubic Information and Outreach Manager
    Gemini Observatory, Hilo, HI
    Email: pmichaud”at”gemini.edu
    Cell: (808) 936-6643
    Desk: (808) 974-2510
    Science Contacts:
    Dr. Ken Hinkle
    National Optical Astronomy Observatory
    950 N Cherry Ave, Tucson AZ 85719 USA
    Email: hinkle”at”noao.edu
    Desk:

    Stellar lifetimes are measured in billions of years, so changes in their appearance rarely take place on a human timescale. Thus an opportunity to observe a star passing from one stage of life to another on a timescale of months to years is very exciting, as there are only a very few examples known. One such star is Sakurai’s Object (V4334 Sgr). First reported by a Japanese amateur astronomer in 1996 as a “nova-like object,” Sakurai’s Object had been only a few years before the faint central star of a planetary nebula. In the 1990’s Sakurai’s Object brightened by a factor of 10000. This brightening has been attributed to a final helium shell flash. In this process the burned out core of the star at the center of the planetary nebula re-ignites.

    The final helium shell flash is violent, ejecting a cloud of dust and gas that forms a thick cocoon around the star blocking all visible light. By 2000 the dust cloud was so thick that Sakurai’s Object was not visible even with the Hubble Space Telescope (HST). Scientists at the National Optical Astronomy Observatory (NOAO) have been observing the sky in the area of Sakurai’s Object waiting for infrared radiation to break through the dust cloud. Infrared radiation penetrates dust much more efficiently than optical light. A detection of the infrared light would mean that the dust cloud is breaking apart, ultimately permitting light from the star to escape.

    Using the Altair adaptive optics (AO) system with the Gemini North telescope on Mauna Kea in Hawai’i to compensate for distortions to starlight caused by the Earth’s atmosphere, two NOAO astronomers were able to observe the shell of escaping material around the star. According to Dr. Richard Joyce, who was in charge of the imaging program, “Using AO at Gemini gave us an unprecedented view into the heart of this object and showed us a number of faint stars where Sakurai’s Object should be.” The team compared the Gemini images to views by the Hubble Space Telescope, taken before Sakurai’s Object had faded from view, to obtain a precise location for the object. The Gemini AO images have a resolution of 0.04 arc second (this is equivalent to asking someone to tell if you are holding up one finger or two – from a distance of 200 miles) which clearly resolved many of the stars that ordinarily would be blurred together from ground-based telescopic views. “The initial Gemini images in 2010 showed a faint fuzzy spot near the Sakurai location. It’s amazing that we could see this level of detail,” says Joyce. “By 2013 Sakurai’s Object was obvious at this location with two ejected clouds thanks to these remarkable observations.”

    Gemini Altair Adaptive Optics System
    Altair adaptive optics (AO) system

    NOAO Gemini North
    NOAO Gemini North

    Dr. Kenneth Hinkle, lead author, says, “Sakurai’s object appears to be forming a bipolar nebula: in the past three years two lobes of gas have been observed moving outward from the central star. The bipolar nebula is roughly aligned to the planetary nebula. The planetary nebula is formed from gas lost more than 10000 years ago by the red giant. The co-alignment suggests that there is either a companion star or planet in the system.“ The accompanying artist’s conception represents what the present expanding shell of gas and dust around the star may look like. Because it is enshrouded in dust, Sakurai’s object is much brighter in the infrared region of the spectrum than in visible light. In this illustration the star appears bright red since blue light from the star is absorbed by the dust.

    bpn
    This image shows an example of a bipolar planetary nebula known as PN Hb 12 — popularly known as Hubble 12 — in the constellation of Cassiopeia. The striking shape of this nebula, reminiscent of a butterfly or an hourglass, was formed as a Sun-like star approached the end of its life and puffed its outer layers into the surrounding space. For bipolar nebulae, this material is funnelled towards the poles of the ageing star, creating the distinctive double-lobed structure.

    bpe
    The figure shows an oil painting done by Stephen Mack that represents what the present expanding shell of gas and dust around the star may look like. Mack is a member of the Tohono O’odham Nation, the Native American tribe on whose land the Kitt Peak National Observatory, which is managed by NOAO, is located.

    Observations using the NASA/ESA Hubble Space Telescope and the [ESO] NTT have found that bipolar planetary nebulae located towards the central bulge of our Milky Way appear to be strangely aligned in the sky — a surprising result given their varied and chaotic formation.

    As stars like the sun reach the end of their lives they expand and cool to become luminous red giants. When their nuclear fuel is exhausted a resulting stellar core, a cooling ember, is called a white dwarf. However, in 10-15 percent of stars like the sun enough hydrogen and helium remains to start nuclear burning again, rapidly re-igniting the faint white dwarf. This phase is called a final flash. While not uncommon, this pulse lasts for such a short time that seeing it is very rare: there are only three stars currently known to be undergoing final flash evolution. Estimates of the frequency of such a final flash object in our galaxy suggest that one occurs about once every ten years. The previous one observed by astronomers erupted in 1919.

    wd
    Image of Sirius A and Sirius B taken by the Hubble Space Telescope. Sirius B, which is a white dwarf, can be seen as a faint pinprick of light to the lower left of the much brighter Sirius A.

    Located in the constellation Sagittarius, in the direction of the center of our Milky Way galaxy, the distance to Sakurai’s object can be measured from the expansion of the dust cloud. The current data show that it is about 6800 to 12000 light years from Earth. As the cloud of debris expands it will be possible to refine our knowledge of the distance and other parameters of this interesting object.

    The team’s results will be published in The Astrophysical Journal.

    The National Optical Astronomy Observatory (NOAO) is operated by Association of Universities for Research in Astronomy Inc. (AURA) under a cooperative agreement with the National Science Foundation.

    See the full article here.

    Gemini North
    Gemini North, Hawai’i

    Gemini South
    Gemini South, Chile
    AURA Icon

    The Gemini Observatory consists of twin 8.1-meter diameter optical/infrared telescopes located on two of the best observing sites on the planet. From their locations on mountains in Hawai‘i and Chile, Gemini Observatory’s telescopes can collectively access the entire sky.
    Gemini was built and is operated by a partnership of six countries including the United States, Canada, Chile, Australia, Brazil and Argentina. Any astronomer in these countries can apply for time on Gemini, which is allocated in proportion to each partner’s financial stake.


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