Tagged: Exoplanets Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 12:02 pm on June 23, 2016 Permalink | Reply
    Tags: , , Exoplanets, Qatar exoplanet survey   

    From Astronomy: “Qatar exoplanet project announces the discovery of three new exoplanets” 

    Astronomy magazine

    Astronomy Magazine

    June 23, 2016
    John Wenz

    The Qatar Exoplanet Survey announced the discovery of three new exoplanets in a paper accepted for publication at the Monthly Notices of the Royal Astronomical Society.

    The three planets are called Qatar-3b, Qatar-4b, and Qatar-5b. All three are “hot Jupiter” planets, gas giants in orbits spanning just a few Earth days around their parent stars. 3b and 5b are roughly the same mass, at 4.31 and 4.32 Jupiter masses, while 4b is about 5.85 Jupiter masses. All three are slightly larger than Jupiter as well, with 4b weighing in as the largest at 1.55 times Jupiter’s radius. 3b orbits in 2.5 days around its parent star, while 4b takes 1.8 days, and 5b takes 2.87 days. All three parent stars are roughly the size of the sun.

    The planets were discovered using the transit method, where dips in starlight give away the presence of a planet. Through the analysis, the astronomers also discovered the Qatar-5 is a metal-rich planet, meaning it comes from later, newer generations of stars that utilize heavier elements in stellar fusion alongside hydrogen-helium fusion.

    Planet transit. NASA/Ames
    Planet transit. NASA/Ames

    As the names imply, these are the third, fourth, and fifth planetary objects found by the Qatar Exoplanet Survey. All five planets discovered are hot Jupiters, which are easier to detect due to their large size and swift orbits, making transit events more common. The last planet found by the survey was in 2011. Since that time, the survey has upgraded their systems and added more telescopes.

    As the names imply, these are the third, fourth, and fifth planetary objects found by the Qatar Exoplanet Survey. All five planets discovered are hot Jupiters, which are easier to detect due to their large size and swift orbits, making transit events more common. The last planet found by the survey was in 2011. Since that time, the survey has upgraded their systems and added more telescopes.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 12:26 pm on June 22, 2016 Permalink | Reply
    Tags: , , , Exoplanets, , Where the Wild (Planet)Things Are   

    From Astrobites: Where the Wild (Planet)Things Are 

    New research shows hot Jupiters find safety in numbers. According to radial velocity data, these giant exoplanets are more commonly found around stars in open clusters.

    Source: Where the Wild (Planet)Things Are

    Title: Search for giant planets in M67 III: excess of hot Jupiters in dense open clusters
    Authors: A. Brucalassi, L. Pasquini, R. Saglia, M.T. Ruiz, P. Bonifacio, I. Leão, B.L. Canto Martins, J.R. de Medeiros, L. R. Bedin, K. Biazzo, C. Melo, C. Lovis, and S. Randich

    First Author’s Institution: Max-Planck für extraterrestrische Physik, Garching bei München, Germany

    Status: Accepted for publication in A&A Journal Letters

    If you wanted to discover a new giant exoplanet, where would you look? New research, shows that star clusters are a good place to start, at least if you want to look for giant exoplanets close to their host star.

    Hot Jupiters are a breed of exoplanets that have masses about or larger than Jupiter and orbit a star in 10 days or less (for comparison, Mercury takes 88 days to go around the Sun). When they were first discovered, they posed a problem to planet formation models as it was thought gas giants could only form far from their host star where it was cool enough for ices to form, which allows for larger planets to be made. Since then, studies have shown these planets could form far out and migrate inwards over their lifetime. This can happen through interactions with the disk in which the planet forms (known as Type II migration), or through gravitational scattering with other planets or nearby stars.

    Brucalassi and her team decided to investigate an open cluster in the Milky Way (Messier 67) to look for hot Jupiters. Over several years they used three different telescopes (the ESO 3.6m telescope, the Hobby Eberly Telescope and the TNG on La Palma of the Canary Islands) to take high-precision spectra of 88 stars, 12 of which are binary stars. This spectra could then be analyzed for small blue- and redshifts which indicate the star is moving slightly. In this case, that movement is caused by the presence of another body, the exoplanet. This method is known as the radial velocity method and is the method that was used in the first exoplanet discoveries. To make sure that each star’s own activity wasn’t affecting its spectra, the group measured the Hα line which shows how active the star’s chromosphere is. Figure 1 shows an example of the radial velocity measurements.

    1
    Figure 1: Radial velocity measurements for YBP401. The coloured dots represent the different telescopes the measurements were made at. The measurements show an exoplanet with a period of just 4.08 days.

    The group’s measurements revealed a new exoplanet around the main sequence star YBP401. They were also able to get better measurements on two stars (YBP1194 and YBP1514) with known hot Jupiters. This brought the total number of hot Jupiters to 3 out of 88 stars. Although 3 might not seem like a very big number, it is larger than the number of hot Jupiters found around field stars (stars not in clusters). For the statistical analysis, Brucalassi compares the number of exoplanets with the number of main sequence and subgiant stars, i.e. stars that are not yet at the ends of their lives. Of the 88 stars, 66 are main sequence or subgiant, and of those only 53 are not binary stars. Most radial velocity studies choose to not observe binary stars so it is important to compare numbers with that in mind. A previous study from 2012 found a hot Jupiter frequency of 1.2% ± 0.38 around field stars. Brucalassi finds 4.5+4.5-2.5% when comparing with only single stars (not including binaries) in M67. To compare with statistics from the Kepler mission, binaries are included, as Kelper also surveys binaries, and the percentage for hot Jupiters in a cluster is 5.6+5.4-2.6%. The Kepler mission finds a frequency of hot Jupiters of just ~0.4%, which is considerably lower. And this trend isn’t seen just in M67. Combining radial velocity surveys for the clusters M67, Hyades, and Praesepe, there are 6 hot Jupiters in 240 surveyed stars, whereas the study from 2012 found only 12 in survey of 836 field stars.

    It’s known that systems with more metals tend to produce more planets and the star’s mass may also have an effect on planet production. However, the clusters stars and field stars are on average the same mass, so this alone cannot account for the differneces. M67 is also at solar metallicity (i.e. it’s stars tend to have the same amount of metals as our Sun) so this can also not account for the excess of hot Jupiters. Brucalassi concludes that the high number of hot Jupiters is due to the environment. Past simulations show that stars in a crowded cluster environment will experience at least one close encounter with another star, which is all that is needed to drive a Jupiter in to a closer orbit. This new research gives further evidence to this theory, putting us one step closer to understanding how exoplanets can form.

    3
    Figure 2: An artist’s rendition of the new hot Jupiter. Click on the image for a full animated video of the M67 cluster. Courtesy of the ESO press release (#eso1621).

     
  • richardmitnick 7:38 am on June 14, 2016 Permalink | Reply
    Tags: , , , Exoplanets   

    From ESO: “VLT Snaps An Exotic Exoplanet ‘First’ “ 

    ESO 50 Large

    European Southern Observatory

    6.13.16
    No writer credit found

    1

    Astronomers hunt for planets orbiting other stars (exoplanets) using a variety of methods. One successful method is direct imaging; this is particularly effective for planets on wide orbits around young stars, because the light from the planet is not overwhelmed by light from the host star and is thus easier to spot.

    This image demonstrates this technique. It shows a T-Tauri star named CVSO 30, located approximately 1200 light-years away from Earth in the 25 Orionis group (slightly northwest of Orion’s famous Belt). In 2012, astronomers found that CVSO 30 hosted one exoplanet (CVSO 30b) using a detection method known as transit photometry, where the light from a star observably dips as a planet travels in front of it.

    Planet transit. NASA
    Planet transit. NASA/Ames

    Now, astronomers have gone back to look at the system using a number of telescopes. The study combines observations obtained with the ESO’s Very Large Telescope (VLT) in Chile, the W. M. Keck Observatory in Hawaii, and the Calar Alto Observatory facilities in Spain.

    Keck Observatory, Mauna Kea, Hawaii, USA
    Keck Observatory Interior
    Keck Observatory, Mauna Kea, Hawaii, USA

    Calar Alto Observatory Province of Almería, SpainCalar Alto Observatory Interior
    Calar Alto Observatory, Province of Almería, Spain

    Using the data astronomers have imaged what is likely to be a second planet! To produce the image, astronomers exploited the astrometry provided by VLT’s NACO and SINFONI instruments.

    ESO/NACO
    ESO/NACO

    ESO SINFONI
    ESO/SINFONI

    This new exoplanet, named CVSO 30c, is the small dot to the upper left of the frame (the large blob is the star itself). While the previously-detected planet, CVSO 30b, orbits very close to the star, whirling around CVSO 30 in just under 11 hours at an orbital distance of 0.008 au, CVSO 30c orbits significantly further out, at a distance of 660 au, taking a staggering 27 000 years to complete a single orbit. (For reference, the planet Mercury orbits the Sun at an average distance of 0.39 au, while Neptune sits at just over 30 au.)

    If it is confirmed that CVSO 30c orbits CVSO 30, this would be the first star system to host both a close-in exoplanet detected by the transit method and a far-out exoplanet detected by direct imaging. Astronomers are still exploring how such an exotic system came to form in such a short timeframe, as the star is only 2.5 million years old; it is possible that the two planets interacted at some point in the past, scattering off one another and settling in their current extreme orbits.
    Link:

    Research paper by Schmidt et al.

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition
    Visit ESO in Social Media-

    Facebook

    Twitter

    YouTube

    ESO Bloc Icon

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

    ESO LaSilla
    LaSilla

    ESO VLT
    VLT

    ESO Vista Telescope
    VISTA

    ESO NTT
    NTT

    ESO VLT Survey telescope
    VLT Survey Telescope

    ALMA Array
    ALMA

    ESO E-ELT
    E-ELT

    ESO APEX
    Atacama Pathfinder Experiment (APEX) Telescope

     
  • richardmitnick 11:53 am on June 8, 2016 Permalink | Reply
    Tags: , , Exoplanets,   

    From Smithsonian: “How Would You React If We Discovered Alien Life?” 

    smithsonian
    Smithsonian.com

    Experts weigh in on what the detection of other life forms might mean to the human race

    June 7, 2016
    David Levine

    1
    The most habitable exoplanets discovered so far – includes Kepler 438b, which is the most Earth-like planet yet discovered. Image credit: University of Puerto Rico at Arecibo

    For more than a century, from George Melies’ A Trip to the Moon to Stephen Spielberg’s E.T. and Close Encounters to this summer’s blockbuster sequel to Independence Day, mass media, and the general public, have pondered what will happen if we ever came into contact with extraterrestrial life forms. Carl Sagan’s book Contact, and Jodie Foster’s movie of the same name, explores one possible scenario in which a Search for Extraterrestrial Intelligence (SETI) scientist (played by Foster) discovers a signal repeating a sequence of prime numbers originating from star system Vega, the 5th brightest star visible from Earth. Even if Contact’s version of an alien encounter is more likely than that presented in Spielberg’s E.T., the possibilities are worth pondering.

    And yet experts believe that the odds of receiving a radio transmission composed of prime numbers or encountering intelligent extraterrestrial life in the near future are “astronomical.” even with Hillary Clinton’s promise that if elected President, she would open up the “X-files” (Area 51).

    But the odds may be increasing due to continuing advances in technology and money. At a press conference held in April in New York City, Russian billionaire and Breakthrough Prize co-founder Yuri Milner, along with famed physicist Stephen Hawking, announced Breakthrough Starshot, a 20-year voyage to the Alpha Centauri star system. Should the existence of planets in the Alpha Centauri system be confirmed, Starshot could provide us with the best measurements of an exoplanet atmosphere we could ever hope to get this century. Milner will spend $100 million dollars to fund the project. Facebook’s founder and CEO, Mark Zuckenberg, is on the project’s board of directors.

    The goal of NASA’s Kepler Mission was to find terrestrial planets in the habitable zone of stars both near and far where liquid water and possibly life might exist. To date, Kepler has confirmed the existence of 2,337 exoplanets, including 1,284 new planets announced as of this writing. In a press release issued by NASA, chief scientist Ellen Stofan, said, “This announcement more than doubles the number of confirmed planets from Kepler. This gives us hope that somewhere out there, around a star much like ours, we can eventually discover another Earth.”


    Transit graph

    But what would happen if we discovered life beyond Earth?

    Christof Koch, president and chief scientific officer of the Allen Institute for Brain Science, believes most people will be excited to learn that there is intelligent life out there. “For some ‘contact” would be a wish come true and fill us with awe. But for others it would raise concerns. One can’t assume that alien cultures are by definition benevolent,” Koch says. “If we look at the history of our world, lesser civilizations were often destroyed by more advanced ones. Would the same happen to us if we encountered an advanced alien civilization?” Hawking has warned against sending messages out into space for this very reason.

    Koch has devoted his life to defining what consciousness is whether it be the internet, robots, animals, etc. Since it is doubtful that our first contact will be with humans from another planet it is important for us to understand what consciousness is so we can better understand what we do discover as we explore space. “The first discovery would probably be bacteria which might excite some scientists but not the general public. Another scenario might be a radio signal whose origin would be questioned. Was it a deliberate signal sent to us or is it random noise that can be explained scientifically? I am not holding my breath for a signal that includes prime numbers,” Koch says.

    Mary A. Voytek is the senior scientist and head of NASA’s Astrobiology Program who started Nexus for Exoplanet System Science to search for life on exoplanets. She notes that NASA scientists are currently looking at the most extreme conditions on Earth to better understand what conditions can support life throughout the universe. “If we can determine what makes a habitable planet on Earth it will help guide us to look for conditions in the universe” she says.

    Voytek notes that NASA acknowledges that the discovery of life has significance beyond science: “In order to fully understand the societal implications, we must talk to the experts-scholars in sociology and the humanities as well as theologians.”

    “When I give lectures about my work ,most people are excited about the possibility of the discovery of extraterrestrial life,” Voytek says. “This is nothing new… The ancient Greek atomists in the fourth century B.C. wrote about it. There is a quote by Democritus that I like to cite. ‘To consider the Earth as the only populated world in infinite space is as absurd as to assert that in an entire field sown with millet only one grain will grow.’”

    Douglas Vakoch, president of Messaging Extraterrestrial Intelligence (METI) has devoted much of his career with SETI to exploring what would happen on first contact and how we could even initiate it through interstellar messages. He says the majority of people believe that intelligent life is widespread in the cosmos.

    3

    2

    4

    5

    6

    7

    8

    9

    10

    11

    He agrees that a discovery of something like a radio signal would result in arguments, as well as a fading lack of interest due to time. “It could take decades or even hundreds of years for us to get a response from a signal we send out. For people who are used to instant communication, this will be frustrating,” Vakoch says.

    Others think we’ll have a more dramatic experience. Susan Schneider, a professor of philosophy and cognitive science at the University of Connecticut and a fellow of the Center for Theological Inquiry, believes that if we do find intelligent life, it will be most likely be in the form of super-intelligent artificial intelligence. “For some people this would be hard to accept. Discovering a civilization that is no longer biological would be scary for us,” But Schneider is optimistic that most people will find the discovery of benevolent intelligent life exciting. “People are excited by the unknown. And the discovery of a new civilization might have many potential benefits. Perhaps an advanced civilization will share their knowledge with us,” Schneider says.

    The Catholic Church has come a long way since the days of Galileo. Pope Francis made headlines when he said he would baptize Martians. Many were surprised at the Pope’s remarks, but the Vatican has been positive about aliens for many years. Father Jose Gabriel Funes, a priest and an astronomer, views aliens as brothers and said the Church has no problem with the idea of intelligent life in the cosmos. Jesuit Brother Guy Consolmagno is the first clergyman to win the Carl Sagan Medal and the current president of the Vatican Observatory Foundation. In a 2014 article in the Christian Post, Consolmagno said “the general public will not be too surprised when life on other planets is eventually discovered, and will react in much the same way it did when news broke in the ’90s that there are other planets orbiting far off stars.”

    A similar view is held by Orthodox Jews. In an e-mail to me, Rabbi Ben Tzion Krasnianski, director of Chabad of the Upper East Side of Manhattan, wrote, “Jews believe in other life forms. The universe is populated with infinite amount of them. They are not physical, however, rather they are angels who are spiritual conscious beings that are beyond anything we could imagine. The Talmud says one angel’s mind is the equivalent of a third of the world’s population’s intelligence combined. For us it’s no surprise that we are not alone in the larger universe.”

    Vakoch said people must keep in mind that we are only at the beginning of exploration. “We have just started looking. It has only been a few hundred years that we’ve been a technologically advanced society. That’s a very small amount of time in our universe.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Smithsonian magazine and Smithsonian.com place a Smithsonian lens on the world, looking at the topics and subject matters researched, studied and exhibited by the Smithsonian Institution — science, history, art, popular culture and innovation — and chronicling them every day for our diverse readership.

     
  • richardmitnick 11:56 am on May 16, 2016 Permalink | Reply
    Tags: , , Exoplanets, , Recent Kepler release of planets   

    From INVERSE: “Identify 1,284 New Exoplanets in One Fell Swoop” 

    INVERSE

    INVERSE

    May 12, 2016
    Neel V. Patel

    Before Tuesday, there were no shortage of theories about what NASA’s discovery announcement would entail. (Full disclosure: I was responsible for much of that speculation.) Then Tuesday hit and we found out exactly what the big news was: NASA scientists just confirmed the identify of 1,284 new exoplanets in the universe — including nine planets that have the potential to be habitable to life.

    It’s an announcement that has already inspired scientists and ordinary individuals around the world to ponder whether we might seriously find extraterrestrial life soon enough. But the new study raises an interesting question: what changed between the last few years and now that allowed scientists to identify so many new exoplanets all at once? Did all of these planets just show up at once? Did we develop better technology? Did the Kepler Space Telescope miraculously get better (after weirdly almost breaking down)? What gives?

    NASA/Kepler Telescope
    NASA/Kepler Telescope

    The answer: It all comes down to a new method of validating exoplanet candidates that provides ”astrophysical false positive probability calculations” for such objects, according to a new paper* published in the latest issue of The Astrophysical Journal. Basically, the new method ascribes a number to every object found by Kepler that determines the likelihood that object is an exoplanet, and not an “imposter.” Call it a planet score. The higher the number, the more likely it’s a planet.

    The new method only allows an object to move from the “candidate” category to “exoplanet” if Kepler researchers can say so with 99 percent reliability or higher.

    1
    This is an artist’s conception of Kepler-20e, the first planet smaller than the Earth discovered to orbit a star other than the sun. A year on Kepler-20e only lasts six days, as it is much closer to its host star than the Earth is to the sun.

    We should slow down at this point and expound on exactly how astronomers find and evaluate potential exoplanets. Basically, through Kepler and a few other instruments**, scientists stare at distant stars and measure the brightness of light emitting from those balls of fiery energy. When a star has a planet in orbit, its brightness will dim as that planet transits past it in relation to the telescope we’re using to watch it (a recent, albeit small, example is Mercury passing in front of the sun). As long as that dimming isn’t just a technical error, it’s a sign that something is passing through the neighborhood. A consistent dimming occurring regularly over time is further evidence it might be a planet.

    In the past, scientists had to pore over the brightness numbers along with assessing a variety of different data that might be attainable, like radio velocity observation or high-resolution imaging. Unfortunately, doing that kind of work is extremely time consuming, and we don’t always have the resources to find what we need.

    So in this day-and-age, we turn to computers for help. Timothy Morton, a Princeton researcher who studies exoplanets, developed a new method for exoplanet validation that combines previous exoplanet observations and the current brightness measurements scientists are gathering with Kepler.

    There are two kinds of simulations. The first looks at how the dimming compares to that from known exoplanets and imposter objects. The second goes a step further and deduces whether dimming is indicative of exoplanet behavior given what we already about how exoplanets are distributed and laid around the Milky Way.

    The two simulations are used to determine the statistical likelihood the object in question is an exoplanet. It’s a faster way of doing this work — and by all accounts, it’s even more accurate. In fact, the method is actually being used to verify previously confirmed exoplanets and determine whether they might actually be false-positives.

    This is crucial for the direction of future exoplanet research. The work accomplished since Kepler’s launch in 2009 has been huge in illustrating just how many other worlds exist in the universe — and it has given humans a staggering amount of hope we may find another habitable planet, or even alien life.

    NASA is already getting ready to launch the Transiting Exoplanet Survey Satellite (TESS) in late 2017, and the James Webb Space Telescope in 2018.

    NASA/TESS
    NASA/TESS

    NASA/ESA/CSA Webb Telescope annotated
    NASA/ESA/CSA Webb Telescope annotated

    Both will play a pivotal role in exoplanet investigations by acquiring lots more data that we’ve ever dealt with. Morton’s model will help our scientists on the ground sift through that data and identify potentially habitable exoplanets faster than we could have hoped.

    Photos via NASA/Ames/JPL-Caltech, NASA/JPL-Caltech

    *SCience paper:
    FALSE POSITIVE PROBABILITIES FOR ALL KEPLER OBJECTS OF INTEREST: 1284 NEWLY VALIDATED PLANETS AND 428 LIKELY FALSE POSITIVES

    **The only other telescope that is specifically referenced, NASA/Spitzer, is referenced in the Science paper.

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 5:40 pm on April 17, 2016 Permalink | Reply
    Tags: , , Exoplanets,   

    From CNN: “The planet hunter searching for another Earth” Sara Seager 

    1
    CNN

    April 15, 2016
    Jacopo Prisco

    “I want to find another Earth. That’s what I’m living for.”
    MIT astrophysicist Sara Seager has been looking at planets beyond our solar system, known as exoplanets, for almost 20 years.
    When the first ones were discovered in the 1990s, many questioned the finding and didn’t think it was real. But since then, with better technology, we have observed more than 6,000 of them, most of which are giant balls of gas.

    Today, the list grows every week.

    With so many planets now coming out of hiding, the race is on to identify one that resembles Earth: a rocky world with liquid water just like ours, and suitable to host life.
    Seager believes she knows how to make that discovery.

    ‘These aren’t planets!’

    It’s not easy to see exoplanets as you can’t just look at them through a telescope. This is due to the blinding light coming from their host stars, which can be very different in size and features compared to our sun. The process is often described as trying to spot a firefly circling a lighthouse, from thousands of miles away.

    The first ones were discovered indirectly, in 1995, by just looking at stars to see if they would wobble slightly, responding to the pull of another object’s gravity.

    At this time, Seager was a graduate student at Harvard searching for a topic for her Ph.D. and she was intrigued by the newborn field of faraway planets.
    “Since the planets were discovered indirectly, most people didn’t believe that the discoveries were real. They’d say to me ‘Why are you doing this? These aren’t planets!’,” says Seager.
    The contrarians weren’t entirely wrong: the wobble can be caused by other factors such as another star and several planet discoveries have been retracted over time for this reason.
    But then a different technique was found to make their hunt easier, called transit.

    Planet transit. NASA
    Planet transit. NASA

    This is when a planet moves in front of its host star and causes the star’s light to dim slightly.

    “One of the planets from the wobble technique showed transit: it went in front of the star at exactly the time it was predicted to and that was basically incontrovertible,” says Seager.
    Exoplanets were real.

    1
    Dwarfing even Jupiter – HD-106906b is a gaseous planet 11 times more massive than Jupiter. The planet is believed to have formed in the center of its solar system, before being sent flying out to the edges of the region by a violent gravitational event. No image credit.

    Alien atmospheres

    Seager did not want to simply look for distant planets. She set her sights on something more specific — their atmosphere. She was the first person to do so.
    “Atmospheres are important because they’re a way to look for signs of life: we look at gases that don’t belong and may have been produced by some life form,” she explains.
    But if seeing an exoplanet is already difficult, how do you observe an atmosphere? For this purpose the light from the star can come in handy. “When a planet transits in front of its star, we can very carefully analyze the atmosphere’s composition, thanks to the light of the star shining through it,” says Seager.

    The process becomes similar to looking at a rainbow.
    “If you look at a rainbow very closely, you see tiny little dark lines between the colors, pieces that are missing. Those lines are there because Earth’s atmosphere is taking away some of the light.”
    The dark lines are like fingerprints for specific gases and special tools can decode which ones are there. In 1999, Seager suggested that one particular element, sodium, should leave a detectable fingerprint.
    “It’s like skunk spray: a tiny bit of sodium can make a very big signature,” she says.

    Seager was right — her prediction was independently confirmed two years later using the Hubble telescope.

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    Sodium was found in the atmosphere of a “Hot Jupiter,” the name given to the first exoplanets ever discovered. These are huge spheres of gas many times larger than Earth — like our Jupiter — orbiting dangerously close to their stars, making them very hot.
    Because of their size, Hot Jupiters are the easiest exoplanets to spot, and hundreds have been found to date. But as they don’t have a solid surface, they are nothing like Earth.
    To find life, we need small, rocky planets — like ours.

    The Goldilocks Zone

    Compared to finding “Hot Jupiters”, searching for rocky planets is far more difficult, mainly because of their smaller size. And when spotting gases, it’s not sodium we’re after.

    “The number one thing we want to see in a planet’s atmosphere is water vapor,” says Seager.
    We see water vapour in some of the giant planets, like Jupiter, as they have it naturally within their atmosphere. “We have not seen that yet in a rocky planet.”
    Detecting water vapor on a rocky planet would be the tell-tale sign of a liquid ocean, and therefore the potential for life. “All life on Earth needs water, and we believe that all life needs a liquid,” says Seager.
    The need for liquid to create life is theorized due to the chemistry of molecules, as they require liquids to react and reform into other things — such as lifeforms. “Water is simply the most abundant liquid out there,” says Seager.
    For a planet to have liquid water, some basic conditions must be met. The planet must be such that its surface temperature is not too hot — or water will boil away — and not too cold — or it will freeze into ice. This all depends on its distance from the parent star: either too close, or too far.
    Astronomers call this sweet spot the “Goldilocks zone,” from the children’s tale “The Three Bears,” in which young Goldilocks likes her porridge “Not too cold, not too hot, but just right.”

    Habitable planets Current Potential Planetary Habitability Laboratory U Puerto Rico Arecibo
    Habitable planets Current Potential Planetary Habitability Laboratory U Puerto Rico Arecibo.

    These planets are not rare, but the challenge in spotting them can make it seem that way.
    “As many as one in five stars like the sun could have a planet with liquid water. And even though this number could be wrong, as things change quickly, we know for sure that small rocky planets are not rare,” says Seager.
    There may be billions of Earth-like planets in our galaxy alone.

    The galaxy’s finest

    Out of the 6,000 planets discovered so far, approximately 2,000 have been confirmed to be actual planets — work is underway on the rest — but only about 30 are considered potentially habitable.

    In 2014, NASA found the first Earth-sized planet orbiting a star in the habitable zone. This was named Kepler-186f — after the Kepler space telescope, used to spot it — and is about 500 light-years away in the constellation Cygnus, the galactic equivalent of our neighbourhood since the Milky Way is about 100,000 light years across.

    NASA/Kepler Telescope
    NASA/Kepler Telescope

    This planet is 10% larger than Earth.
    Described by NASA as “a significant step toward finding worlds like our planet Earth,” Kepler-186f orbits around a type of common star known as a red dwarf, which is about half the size of our sun.
    Then, in 2015, astronomers found the first Earth-like planet orbiting a star just like our sun, called Kepler-452b. This was dubbed Earth’s “bigger, older cousin,” as the planet is 60% larger than Earth and completes one orbit in 385 days, making its years remarkably close to our own
    With our current technology, however, it’s hard to know much more than the size of an exoplanet and how far it is from its star.
    But that’s about to change.

    New eyes in the sky

    The majority of exoplanet discoveries have been made by the Kepler space telescope, after which most of them have been named. Launched in 2009, the telescope has now entered emergency mode 75 million miles away from Earth, due to a malfunction.
    To study the atmospheres of potential Earth twins, scientists need new eyes in the sky.
    To date, Seager has only been able to study the atmospheres of a handful of exoplanets — all gas giants — but she’s involved in a new NASA program launching in 2017 to just scout the brightest nearby stars for small rocky planets in the habitable zone.


    Access mp4 video here .

    Called TESS (Transiting Exoplanet Survey Satellite), the two-year mission will accumulate data that will then be fed into the James Webb Space Telescope, the next Hubble, which is due to launch in 2018: “It’s going to be amazing,” says Seager.

    NASA/TESS
    NASA/TESS

    NASA/ESA/CSA Webb Telescope annotated
    NASA/ESA/CSA Webb Telescope annotated

    The James Webb telescope — named after the head of NASA during the pioneering era of the 1960s — will look at the cosmos with unprecedented clarity thanks to its use of a primary mirror about five times larger than Hubble’s. It will also offer direct imaging of exoplanets by blocking the blinding light of their host stars with special instruments that make them more visible. This will allow Seager and other astronomers to study exoplanets like never before.
    Seager believes many of the planets in their search will be the rocky, watery worlds she’s been looking for.
    “I’m absolutely confident they’re out there.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 6:31 pm on April 11, 2016 Permalink | Reply
    Tags: , , , Exoplanets   

    From Carnegie: “New tool refines exoplanet search” 

    Carnegie Institution for Science
    Carnegie Institution for Science

    April 11, 2016
    No writer credit found

    Planet-hunting is an ongoing process that’s resulting in the discovery of more and more planets orbiting distant stars. But as the hunters learn more about the variety among the tremendous number of predicted planets out there, it’s important to refine their techniques. New work led by Carnegie’s Jonathan Gagné, Caltech’s Peter Gao, and Peter Plavchan from Missouri State University reports on a technological upgrade for one method of finding planets or confirming other planetary detections. The result is published by The Astrophysical Journal.

    One of the most-popular and successful techniques for finding and confirming planets is called the radial velocity method. A planet is obviously influenced by the gravity of the star it orbits; that’s what keeps it in orbit. This technique takes advantage of the fact that the planet’s gravity also affects the star in return. As a result, astronomers are able to detect the tiny wobbles the planet induces as its gravity tugs on the star. Using this method, astronomers have detected hundreds of exoplanets.

    For certain kinds of low-mass stars, however, there are limitations to the standard radial velocity method, which can cause false positives—in other words, find something that looks like a planet, but isn’t.

    To address this issue, Gagné, Gao, and Plavchan decided to use the radial velocity technique, but they examined a different, longer wavelength of light.

    “Switching from the visible spectrum to the near-infrared, the wobble effect caused by an orbiting planet will remain the same regardless of wavelength,” Gagné explained. “But looking in the near-infrared will allow us to reject false positives caused by sunspots and other phenomena that will not look the same in near-infrared as they do in visible light,”

    Radial velocity work in the near-infrared wavelengths has been conducted before, but it has trailed behind planet hunting in the visible spectrum, partially due to technical challenges. The research team was able to develop a better calibration tool to improve the overall technology for near-infrared radial velocity work, which should make it a better option going forward.

    They examined 32 low-mass stars using this technological upgrade at the NASA Infrared Telescope Facility atop Mauna Kea, Hawaii.

    NASA Infrared Telescope facility
    NASA Infrared Telescope facility Mauna Kea Hawaii USA

    Their findings confirmed several known planets and binary systems, and also identified a few new planetary candidates.

    “Our results indicate that this planet-hunting tool is precise and should be a part of the mix of approaches used by astronomers going forward,” Gao said. “It’s amazing to think that two decades ago we’d only just confirmed exoplanets actually existed and now we’re able to refine and improve those methods for further discoveries.”

    Carnegie planet hunting tool cell that contains methane gas
    Carnegie planet hunting tool cell that contains methane gas

    Other members of the team were: Guillem Anglada-Escude of University of London and the Centre for Astrophysics Research; Elise Furlan, Carolyn Brinkworth, Chas Beichman, and David Ciardi of the NASA Exoplanet Science Institute (Brinkworth also of the National Center for Atmospheric Research); Cassy Davison, Todd Henry, and Russel White of Georgia State University; Angelle Tanner of Mississippi State University; Adric Riedel and Michael Bottom of the California Institute of Technology; David Latham and John Johnson of the Harvard-Smithsonian Center for Astrophysics; Sean Mills of University of Chicago; Kent Wallace, Bertrand Mennesson, Gautam Vasisht, and Timothy Crawford of the Jet Propulsion Laboratory; Kaspar Von Braun and Lisa Prato of Lowell Observatory; Stephen Kane of San Francisco State University; Eric Mamajek of University of Rochester; Bernie Walp of the NASA Dryden Flight Research Center; Raphael Rougeot of the Euroopean Space Research and Technology Centre; Claire Geneser of Missouri State; and Joseph Catanzarite of NASA Ames Research Center.

    This work was supported by an Infrared Processing and Analysis Center (IPAC) fellowship, a grant from the Fond de Recherche Québécois – Nature et Technologie and the Natural Science, a grant from the Engineering Research Council of Canada, an iREx postdoctoral Fellowship, and a JPL Research and Technology Development Grant. This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by the National Aeronautics and Space Administration (NASA) through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Carnegie Institution of Washington Bldg

    Andrew Carnegie established a unique organization dedicated to scientific discovery “to encourage, in the broadest and most liberal manner, investigation, research, and discovery and the application of knowledge to the improvement of mankind…” The philosophy was and is to devote the institution’s resources to “exceptional” individuals so that they can explore the most intriguing scientific questions in an atmosphere of complete freedom. Carnegie and his trustees realized that flexibility and freedom were essential to the institution’s success and that tradition is the foundation of the institution today as it supports research in the Earth, space, and life sciences.

     
  • richardmitnick 2:04 pm on March 15, 2016 Permalink | Reply
    Tags: , , Exoplanets,   

    From phys.org: “Four new giant planets detected around giant stars” 

    physdotorg
    phys.org

    March 15, 2016
    Tomasz Nowakowski

    Gas giants
    Artist’s concept of a giant extrasolar planet. Credit: NASA/JPL-Caltech.

    An international team of astronomers reports the discovery of four new giant exoplanets orbiting stars much bigger than our sun. The newly detected alien worlds are enormous, with masses from 2.4 to 5.5 the mass of Jupiter and have very long orbital periods ranging from nearly two to slightly more than four Earth years. The findings were published on Mar. 11 in a research paper available online at arXiv.org.

    The team, led by Matias Jones of the Pontifical Catholic University of Chile, made the discovery during observations under the EXPRESS (EXoPlanets aRound Evolved StarS) radial velocity program. They used two telescopes located in the Atacama desert in Chile: the 1.5 m telescope at the Cerro Tololo Inter-American Observatory and the 2.2 m telescope at La Silla observatory. Complementary observations were conducted at the 3.9 m Anglo-Australian telescope [AAT] in Australia.

    NOAO SMARTS
    NOAO /CTIO SMARTS CHIRON 1.5 meter telescope

    NOAO Cerro Tolo
    NOAO CTIO

    ESO 2.2 meter telescope
    ESO 2.2 meter telescope at La Silla

    ESO LaSilla
    La Silla

    AAO Anglo Australian Telescope Exterior
    AAO Anglo Australian Telescope Interior
    AAT

    Using spectrographs mounted on these telescopes, the researchers were monitoring a sample of 166 bright giant stars that are observable from the southern hemisphere. They took several spectra for each of the stars in the sample thanks to these instruments. The observation campaign lasted from 2009 to 2015.

    The astronomers have computed a series of precision radial velocities of four giant stars: HIP8541, HIP74890, HIP84056 and HIP95124. According to them, these velocities show periodic signal variations. The team concluded that the most probable explanation of the periodic radial velocity signals observed in these stars must be the presence of planetary companions.

    “These velocities show periodic signals, with semi-amplitudes between approximately 50 to 100 ms−1, which are likely caused by the doppler shift induced by orbiting companions. We performed standard tests (chromospheric emission, line bisector analysis and photometric variability) aimed at studying whether these radial velocity signals have an intrinsic stellar origin. We found no correlation between the stellar intrinsic indicator with the observed velocities,” the paper reads.

    HIP8541b is the most massive of the newly found quartet of planets. With a mass of about 5.5 Jupiter masses, this exoplanet also has a much longer orbital period than the other three worlds, equal to 1,560 days. Its parent star is slightly more massive than the sun and has a radius of nearly eight solar radii.

    HIP74890b and HIP84056b are very similar in terms of mass and orbital period. The mass of HIP74890b is estimated to be 2.4 Jupiter masses, what is about 92 percent of the mass of HIP84056b. The more massive planet of this comparable duo has an orbital period lasting nearly 819 days – about three fewer days than the other planet. Their host stars are also of similar mass and size, about 1.7 the mass of the sun, with a radius of 5.03 (HIP 84056) and 5.77 (HIP 74890) solar radii.

    Among the exoplanets described in the paper, the one with the shortest orbital period (562 days), is designated HIP95124b. It has a mass of 2.9 Jupiter masses and orbits a star nearly two times more massive than the sun, with a radius of 5.12 solar radii.

    The discovery of these planets also yielded interesting results about correlations between the stellar properties and the occurrence rate of planets. The researchers have found that giant planets are preferentially detected around metal-rich stars.

    “We also present a statistical analysis of the mass-metallicity correlations of the planet-hosting stars in our sample. (…) We show that the fraction of giant planets increases with the stellar mass in the range between 1 to 2.1 solar masses, despite the fact that planets are more easily detected around less massive stars,” the scientists noted.

    The team concluded that the high fraction of multiple systems observed in giant stars is a natural consequence of the planet formation mechanism around intermediate-mass stars.

    More information: Four new planets around giant stars and the mass-metallicity correlation of planet-hosting stars, arXiv:1603.03738 [astro-ph.EP] arxiv.org/abs/1603.03738

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    About Phys.org in 100 Words

    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 3:47 pm on March 9, 2016 Permalink | Reply
    Tags: , , Exoplanets,   

    From Kepler: “NASA’s K2 mission: The Kepler Space Telescope’s Second Chance to Shine” 

    NASA Kepler Logo

    NASA Kepler Telescope
    NASA/Kepler

    March 9, 2016
    Michele Johnson
    Ames Research Center, Moffett Field, Calif.
    650-604-6982
    michele.johnson@nasa.gov

    K2 How It Will Work
    K2 How It Will Work.
    Engineers developed an innovative way to stabilize and control the spacecraft. This technique of using the sun as the “third wheel” has Kepler searching for planets again, but also making discoveries on young stars to supernovae. Credits: NASA Ames/W Stenzel

    The engineers huddled around a telemetry screen, and the mood was tense. They were watching streams of data from a crippled spacecraft more than 50 million miles away – so far that even at the speed of light, it took nearly nine minutes for a signal to travel to the spacecraft and back.

    It was late August 2013, and the group of about five employees at Ball Aerospace in Boulder, Colorado, was waiting for NASA’s Kepler space telescope to reveal whether it would live or die. A severe malfunction had robbed the planet-hunting Kepler of its ability to stay pointed at a target without drifting off course.

    The engineers had devised a remarkable solution: using the pressure of sunlight to stabilize the spacecraft so it could continue to do science. Now, there was nothing more they could do but wait for the spacecraft to reveal its fate.

    “You’re not watching it unfold in real time,” said Dustin Putnam, Ball’s attitude control lead for Kepler. “You’re watching it as it unfolded a few minutes ago, because of the time the data takes to get back from the spacecraft.”

    Finally, the team received the confirmation from the spacecraft they had been waiting for. The room broke out in cheers. The fix worked! Kepler, with a new lease on life, was given a new mission as K2. But the biggest surprise was yet to come. A space telescope with a distinguished history of discovering distant exoplanets – planets orbiting other stars – was about to outdo even itself, racking up hundreds more discoveries and helping to usher in entirely new opportunities in astrophysics research.

    “Many of us believed that the spacecraft would be saved, but this was perhaps more blind faith than insight,” said Tom Barclay, senior research scientist and director of the Kepler and K2 guest observer office at NASA’s Ames Research Center in California’s Silicon Valley. “The Ball team devised an ingenious solution allowing the Kepler space telescope to shine again.”

    The discoveries roll in

    A little more than two years after the tense moment for the Ball engineers, K2 has delivered on its promise with a breadth of discoveries. Continuing the exoplanet-hunting legacy, K2 has discovered more than three dozen exoplanets and with more than 250 candidates awaiting confirmation. A handful of these worlds are near-Earth-sized and orbit stars that are bright and relatively nearby compared with Kepler discoveries, allowing scientists to perform follow-up studies. In fact, these exoplanets are likely future targets for the Hubble Space Telescope and the forthcoming James Webb Space Telescope (JWST), with the potential to study these planets’ atmospheres in search of signatures indicative of life.

    NASA Hubble Telescope
    NASA/ESA Hubble

    NASA Webb telescope annotated
    NASA/ESA/CSA JWST

    K2 also has astronomers rethinking long-held planetary formation theory, and the commonly understood lonely “hot Jupiter” paradigm. The unexpected discovery of a star with a close-in Jupiter-sized planet sandwiched between two smaller companion planets now has theorists back at their computers reworking the models, and has sent astronomers back to their telescopes in search of other hot Jupiter companions.

    “It remains a mystery how a giant planet can form far out and migrate inward leaving havoc in its wake and still have nearby planetary companions,” said Barclay.

    Like its predecessor, K2 searches for planetary transits – the tiny, telltale dip in the brightness of a star as a planet crosses in front – and for the first time caught the rubble from a destroyed exoplanet transiting across the remains of a dead star known as a white dwarf. Exoplanets have long been thought to orbit these remnant stars, but not until K2 has the theory been confirmed.

    K2 has fixed its gaze on regions of the sky with densely packed clusters of stars which has revealed the first transiting exoplanet in such an area, popularly known as the Hyades star cluster. Clusters are exciting places to find exoplanets because stars in a cluster all form around the same time, giving them all the same “born-on” date. This helps scientists understand the evolution of planetary systems.

    The repurposed spacecraft boasts discoveries beyond the realm of exoplanets. Mature stars – about the age of our sun and older – largely populated the original single Kepler field of view. In contrast, many K2 fields see stars still in the process of forming. In these early days, planets also are assembled and by looking at the timescales of star formation, scientists gain insight into how our own planet formed.

    Studies of one star-forming region, called Upper Scorpius, compared the size of young stars observed by K2 with computational models. The result demonstrated fundamental imperfections in the models. While the reason for these discrepancies is still under debate, it likely shows that magnetic fields in stars do not arise as researchers expect.

    Looking in the ecliptic – the orbital path traveled around the sun by the planets of our solar system and the location of the zodiac – K2 also is well equipped to observe small bodies within our own solar system such as comets, asteroids, dwarf planets, ice giants and moons. Last year, for instance, K2 observed Neptune in a dance with its two moons, Triton and Nereid. This was followed by observations of Pluto and Uranus.

    “K2 can’t help but observe the dynamics of our planetary system, ” said Barclay. “We all know that planets follow laws of motion but with K2 we can see it happen.”

    These initial accomplishments have come in the first year and a half since K2 began in May 2014, and have been carried off without a hitch. The spacecraft continues to perform nominally.

    Searching for far out worlds

    In April, K2 will take part in a global experiment in exoplanet observation with a special observing period or campaign, Campaign 9. In this campaign, both K2 and astronomers at ground-based observatories on five continents will simultaneously monitor the same region of sky towards the center of our galaxy to search for small planets, such as the size of Earth, orbiting very far from their host star or, in some cases, orbiting no star at all.

    For this experiment, scientists will use gravitational microlensing – the phenomenon that occurs when the gravity of a foreground object, such as a planet, focuses and magnifies the light from a distant background star. This detection method will allow scientists to find and determine the mass of planets that orbit at great distances, like Jupiter and Neptune do our sun.

    Design by community

    What could turn out to be one of the most important legacies of K2 has little to do with the mechanics of the telescope, now operating on two wheels and with an assist from the sun.

    The Kepler mission was organized along traditional lines of scientific discovery: a targeted set of objectives carefully chosen by the science team to answer a specific question on behalf of NASA – how common or rare are “Earths” around other suns?

    K2’s modified mission involves a whole new approach– engaging the scientific community at large and opening up the spacecraft’s capabilities to a broader audience.

    “The new approach of letting the community decide the most compelling science targets we’re going to look at has been one of the most exciting aspects,” said Steve Howell, the Kepler and K2 project scientist at Ames. “Because of that, the breadth of our science is vast, including star clusters, young stars, supernovae, white dwarfs, very bright stars, active galaxies and, of course, exoplanets.”

    In the new paradigm, the K2 team laid out some broad scientific objectives for the mission and planned to operate the spacecraft on behalf of the community.

    Kepler’s field of view surveyed just one patch of sky in the northern hemisphere. The K2 ecliptic field of view provides greater opportunities for Earth-based observatories in both the northern and southern hemispheres, allowing the whole world to participate.

    With more than two years of fuel remaining, the spacecraft’s scientific future continues to look unexpectedly bright.

    For more information about the Kepler and K2 missions, visit:

    http://www.nasa.gov/kepler

    Authored by Michele Johnson and H. Pat Brennan/JPL

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The Kepler Mission, NASA Discovery mission #10, is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planets in or near the habitable zone→ and determine the fraction of the hundreds of billions of stars in our galaxy that might have such planets.
    The operations phase of the Kepler mission is managed for NASA by the Ames Research Center, Moffett Field, CA. NASA’s Jet Propulsion Laboratory (JPL), Pasadena, CA, managed the mission through development, launch and the start of science operations. Dr. William Borucki of NASA Ames is the mission’s Science Principal Investigator. Ball Aerospace and Technologies Corp., Boulder, CO, developed the Kepler flight system.

    In October 2009, oversight of the Kepler project was transferred from the Discovery Program at NASA’s Marshall Space Flight Center, Huntsville, AL, to the Exoplanet Exploration Program at JPL

    K2

    Extending Kepler’s power to the ecliptic

    The loss of a second of the four reaction wheels on board the Kepler spacecraft in May 2013 brought an end to Kepler’s four plus year science mission to continuously monitor more than 150,000 stars to search for transiting exoplanets. Developed over the months following this failure, the K2 mission represents a new concept for spacecraft operations that enables continued scientific observations with the Kepler space telescope. K2 became fully operational in June 2014 and is expected to continue operating until 2017 or 2018.

    NASA image

    NASA JPL Icon

     
  • richardmitnick 7:12 am on February 8, 2016 Permalink | Reply
    Tags: , Exoplanets,   

    From New Scientist: “How Do You Find an Exoplanet? An insider account gives top tips” 

    NewScientist

    New Scientist

    3 February 2016
    Lewis Dartnell

    ESO VLT
    Soon, Chile’s giant telescope will search for Earth-like exoplanets ESO/S. Bruner

    ASTRONOMY has changed a lot in the days since you had to go and sit for hours with your eyeball at the focal point of a 5-metre-diameter telescope atop a mountain.

    This is quickly evident in How Do You Find an Exoplanet? by John Asher Johnson, formerly a leading researcher at NASA. In 2012, his team discovered three exoplanets orbiting a red dwarf, including the smallest found to date. Now a professor at Harvard University, Johnson’s enthusiasm for his vibrant field is palpable in this valuable, concise guide for amateur astronomers and anyone else not afraid of a few technicalities.

    Today, telescopes are controlled from a computer in a heated room. We have also lived through a revolution in our understanding of the cosmos. At the time of writing, we have discovered 2042 worlds orbiting other stars. This is one of the hottest areas in current research, with new finds making headlines almost weekly.

    Since these remote planets are vanishingly dim alongside the overwhelming glare of their host stars, how do we find them? Johnson rattles through the astronomers’ main tricks. The two most successful techniques involve measuring the radial velocity, or wobble, of a star as it is tugged by an orbiting planet, and registering the minuscule dimming of starlight as a planet transits across the face of a star.

    We are also getting good at capturing images of exoplanets alongside their stars. And then there is microlensing, where an exoplanet is detected by the way its gravity focuses the light of a distant background star. [Albert] Einstein’s general theory of relativity predicts this effect, but attempts to apply it to astronomy were abandoned in 1936 because of the limits of photographic plate technology at the time.

    The greatest value of reading an “insider” book, though, is the insight the author can give us into what we can expect in the near future. For my money, the most exciting discoveries will come from ESPRESSO – a particularly apt acronym for this nocturnal profession – which stands for Echelle Spectrograph for Rocky Exoplanet and Stable Spectroscopic Observations.

    ESO Espresso
    Espresso in the clean room

    This ultra-high-resolution spectrometer will soon be installed in the [ESO] Very Large Telescope in northern Chile, where it will simultaneously harness the light-gathering capabilities of four huge 8.2- metre telescopes. By measuring the wobble of a targeted star down to a velocity of just 10 centimetres per second, ESPRESSO will be able to detect Earth-like planets in the habitable zone of their star.

    As those headlines about new exoplanets increase, after reading this book, you will be able to say you predicted as much.

    How Do You Find an Exoplanet?
    John Asher Johnson
    Princeton University Press

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
Follow

Get every new post delivered to your Inbox.

Join 583 other followers

%d bloggers like this: