28
Mar 12

Many Billions of Rocky Planets in the Habitable Zones around Red Dwarfs in the Milky Way

Source: ESO Science Release eso1214


Artist’s impression of sunset on the super-Earth world Gliese 667 Cc.
Image credits: ESO/L. Calçada.

A new result from ESO’s HARPS planet finder shows that rocky planets not much bigger than Earth are very common in the habitable zones around faint red stars. The international team estimates that there are tens of billions of such planets in the Milky Way galaxy alone, and probably about one hundred in the Sun’s immediate neighbourhood. This is the first direct measurement of the frequency of super-Earths around red dwarfs, which account for 80% of the stars in the Milky Way.(read more)

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23
Feb 12

Hubble Reveals a New Class of Extrasolar Planet

Source:ESA/Hubble Science Release heic1204


Artist's impression of Exoplanet GJ 1214b.
Image credits:NASA, ESA, and D. Aguilar.

Observations by the NASA/ESA Hubble Space Telescope have come up with a new class of planet, a waterworld enshrouded by a thick, steamy atmosphere. It’s smaller than Uranus but larger than Earth. (read more)

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27
Jan 12

NASA's Kepler announces 11 planetary systems hosting 26 planets

Source: NASA Kepler


Kepler's Planetary Systems' Orbits.
Image credits: NASA Ames/Dan Fabrycky,
University of California, Santa Cruz

NASA's Kepler mission has discovered 11 new planetary systems hosting 26 confirmed planets. These discoveries nearly double the number of verified planets and triple the number of stars known to have more than one planet that transits, or passes in front of, the star. Such systems will help astronomers better understand how planets form.

The planets orbit close to their host stars and range in size from 1.5 times the radius of Earth to larger than Jupiter. Fifteen are between Earth and Neptune in size. Further observations will be required to determine which are rocky like  Earth and which have thick gaseous atmospheres like Neptune. The planets orbit their host star once every six to 143  days. All are closer to their host star than Venus is to our sun. (learn more)

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14
Jan 12

Planet Population is Plentiful

Source: ESO Science Release eso1204


Planets everywhere (artist's impression).
Image credits: ESO/M. Kornmesser

An international team, including three astronomers from the European Southern Observatory (ESO), has used the technique of gravitational microlensing to measure how common planets are in the Milky Way. After a six-year search that surveyed millions of stars, the team concludes that planets around stars are the rule rather than the exception. The results appeared in the journal Nature on 12 January 2012. (read more)

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12
Jan 12

Kepler Mission Finds Three Smallest Exoplanets

Source: NASA News


Artist's impression of the mini planetary system.
Image credit: NASA/JPL-Caltech

Astronomers using data from NASA's Kepler mission have discovered the three smallest planets yet detected orbiting a star beyond our sun. The planets orbit a single star, called KOI-961, and are 0.78, 0.73 and 0.57 times the radius of Earth. The smallest is about the size of Mars.

All three planets are thought to be rocky like Earth, but orbit close to their star. That makes them too hot to be in the habitable zone, which is the region where liquid water could exist. Of the more than 700 planets confirmed to orbit other stars - called exoplanets - only a handful are known to be rocky. (read more)

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9
Dec 11

NASA's Kepler Confirms Its First Planet in Habitable Zone of Sun-Like Star

Source: NASA


Artist's conception of Kepler-22b. Image credit: NASA/Ames/JPL-Caltech.

NASA's Kepler mission has confirmed its first planet in the "habitable zone," the region where liquid water could exist on a planet's surface. Kepler also has discovered more than 1,000 new planet candidates, nearly doubling its  previously known count. Ten of these candidates are near-Earth-size and orbit in the habitable zone of their host star. Candidates require follow-up observations to verify they are actual planets.

The newly confirmed planet, Kepler-22b, is the smallest yet found to orbit in the middle of the habitable zone of a star similar to our sun. The planet is about 2.4 times the radius of Earth. Scientists don't yet know if Kepler-22b has a predominantly rocky, gaseous or liquid composition, but its discovery is a step closer to finding Earth-like planets.

Previous research hinted at the existence of near-Earth-size planets in habitable zones, but clear confirmation proved elusive. Two other small planets orbiting stars smaller and cooler than our sun recently were confirmed on the very edges of the habitable zone, with orbits more closely resembling those of Venus and Mars. (read more)

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23
Oct 11

Comet storm in a nearby Star System

Source: NASA Science News and NASA News


Artist's impression of comet storm around Eta Corvi. Image credit: NASA.

NASA's Spitzer Space Telescope has detected signs of icy bodies raining down in an alien solar system. The downpour resembles our own solar system several billion years ago during a period known as the "Late Heavy Bombardment." (read more)

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18
Sep 11

CoRoT-2A: Star blasts Planet with X-rays

Source: NASA/CXC-Chandra


Image credits:X-ray: NASA/CXC/Univ of Hamburg/S.Schröter et al;
Optical: NASA/NSF/IPAC-Caltech/UMass/2MASS, UNC/CTIO/PROMPT;
Illustration: NASA/CXC/M.Weiss

A nearby star, named CoRoT-2a,  has a planet in close orbit around it. The separation between the star and planet is only about 3 percent of the distance between the Earth and the Sun, causing some exotic effects not seen in our solar system. Chandra has now found that the planet is under heavy X-ray bombardment from its star. (Read more)

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17
Sep 11

Kepler discovery confirms first planet orbiting two stars

Source: NASA-Kepler Press Release


Artist's concept of Kepler-16b. Image credits: NASA/JPL-Caltech/T. Pyle.

The existence of a world with a double sunset, as portrayed in the film Star Wars more than 30 years ago, is now a scientific fact. NASA's Kepler mission has made the first unambiguous detection of a circumbinary planet - a planet orbiting two stars - 200 light-years from Earth.

Unlike Star Wars' Tatooine, the planet is cold, gaseous and not thought to harbor life, but its discovery demonstrates the diversity of planets in our galaxy. Previous research has hinted at the existence of circumbinary planets, but clear confirmation proved elusive. Kepler detected such a planet, known as Kepler-16b, by observing transits, where the brightness of a parent star dims from the planet crossing in front of it. (read source)

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13
Sep 11

Fifty New Exoplanets Discovered by HARPS

Source: ESO Science Release eso1134


Artist’s impression of the planet orbiting HD 85512 in  Vela.
Image credits: ESO/M. Kornmesser

Astronomers using ESO’s world-leading exoplanet hunter HARPS have today announced a rich haul of more than 50 new exoplanets, including 16 super-Earths, one of which orbits at the edge of the habitable zone of its star. By studying the properties of all the HARPS planets found so far, the team has found that about 40% of stars similar to the Sun have at least one planet lighter than Saturn.(read more)

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30
Jul 11

How Astronomers May Hunt for Life on Alien Planets

Source: SPACE.COM


This chart explains how astronomers measure the signatures of chemicals in the atmospheres of exoplanets.
Image credits: NASA/JPL-Caltech

Any sulfurous molecules that astronomers spot on alien worlds might be a way to reveal whether or not those distant planets host life, researchers suggest.

On Earth, microbes can live off the energy available in sulfurous molecules that volcanoes release, essentially "breathing" these compounds the way humans breathe oxygen. If a similar kind of metabolism evolved on an extrasolar planet, the sulfurous molecules detected in the atmosphere of that world might help reveal the presence of alien life, according to researcher Renyu Hu, a doctoral student in planetary science at MIT.

To see what telltale signs any sulfur-dependent life might generate, Hu and his colleagues modeled Earth-sized planets in the habitable zones of sun-like stars — that is, areas where worlds could  have liquid water on their surfaces. These simulated planets possessed nitrogen-based atmospheres like Earth but 1,000 times more sulfur. (read more)

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5
Jul 11

Hubble makes its millionth observation

Source: ESA/Hubble and HubbleSite


Artist's impression of of exoplanet HAT-P-7b.
Image credits: NASA, ESA and G. Bacon (STScI).

The NASA/ESA Hubble Space Telescope has made its millionth observation since its launch 21 years ago. The telescope  was used to search for the chemical signature of water in the atmosphere of planet HAT-P-7b, a gas giant larger than Jupiter which orbits the star HAT-P-7. (read more)

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25
May 11

Kepler-10c and a New Method to Validate Planets

Source: Kepler@NASA


Artist's conception of Kepler-10 Stellar Family Portrait.
Image credit: NASA/Ames/JPL-Caltech.

Today Kepler team is announcing another member of the Kepler-10 family, called Kepler-10c (larger foreground object in the image on this page). It has a radius of 2.2 times that of Earth's, and it orbits the star every 45 days. Both Kepler-10b and 10c would be blistering hot worlds.

The Kepler-10 system is located about 560 light-years away near the Cygnus and Lyra constellations. Kepler has discovered two planets around this star. Kepler-10b is, to date, the smallest known rocky exoplanet, or planet outside our solar system (dark spot against yellow sun). This planet, which has a radius of 1.4 times that of Earth's, whips around its star every .8 days. Its discovery was announced in Jan. 2011. (read more)

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24
May 11

Kepler’s Astounding Haul of Multiple Planet Systems

Source: Kepler@NASA


Kepler's discoveries. Image credit: NASA/Wendy Stenzel.

NASA’s Kepler spacecraft is proving itself to be a prolific planet hunter. Within just the first four months of data, astronomers have found evidence for more than 1,200 planetary candidates. Of those, 408 reside in systems containing two or more planets, and most of those look very different than our solar system.

In particular, the Kepler systems with multiple planets are much flatter than our solar system. They have to be for Kepler to spot them. Kepler watches for a planet to cross in front of its star, blocking a tiny fraction of the star’s light. By measuring how much the star dims during such a transit, astronomers can calculate the planet’s size, and by observing the time between successive events they can derive the orbital period – how long it takes the planet to revolve around its star.

To see a transit, the planet’s orbit must be edge-on to our line of sight. To see multiple transiting planets, they all must be edge-on (or nearly so).(read more)

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16
May 11

Free-Floating Planets May Be More Common Than Stars

Source: NASA Science News


Artist's concept of a Jupiter-like planet alone in the dark of space, floating freely without a parent star.
Image credits: NASA/JPL-Caltech

Astronomers have discovered a new class of planets floating alone in the dark of space. These lone worlds are probably outcasts from developing planetary systems and, moreover, they could be twice as numerous as the stars themselves. (read more)

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24
Feb 11

ESO makes probable first planet formation detection

Source: ESO Science Release eso1106 - Planet Formation in Action? — Astronomers may have found the first object clearing its path in the natal disc surrounding a young star


Artist’s impression of the disc around the young star T Cha.
Image credit: ESO/L.Calçada.

Using ESO’s Very Large Telescope an international team of astronomers has been able to study the short-lived disc of material around a young star that is in the early stages of making a planetary system. For the first time a smaller companion could be detected that may be the cause of the large gap found in the disc. Future observations will determine whether this companion is a planet or a brown dwarf.(read more)

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23
Feb 11

Orrery of Kepler’s Exoplanets

Source: YouTube /dfabrycky's Channel

The video above presents all the multiple-planet systems discovered by Kepler as of 2/2/2011; orbits go through the entire mission (3.5 years). Hot colors to Cool colors (Red to yellow to green to cyan to blue to gray) are Big planets to Smaller planets, relative to the other planets in the system.

In this video the author presents all the multiple-planet systems discovered by Kepler as of 2/2/2011 that have orbits that go through quarters Q0-Q2. Hot colors to Cool colors (Red to yellow to green to cyan to blue to gray) are Big planets to Smaller planets, relative to the other planets in the system.

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3
Feb 11

NASA Finds Earth-Size Planet Candidates In Habitable Zone, Six Planet System

Source: NASA Kepler


Kepler's planet candidates by size.
Image credit: NASA/Wendy Stenzel

NASA's Kepler mission has discovered its first Earth-size planet candidates and its first candidates in the habitable zone, a region where liquid water could exist on a planet's surface. Five of the potential planets are near Earth-size and orbit in the habitable zone of smaller, cooler stars than our sun.(read more)

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10
Jan 11

NASA's KEPLER mission discovers its first rocky planet

Source: NASA News Release 11-007
by Trent J. Perrotto and Rachel Hoover

Artist concept of Kepler 10b. Credit: NASA.

NASA's Kepler mission confirmed the discovery of its first rocky planet, named Kepler-10b. Measuring 1.4 times the size of Earth, it is the smallest planet ever discovered outside our solar system.

The discovery of this so-called exoplanet is based on more than eight months of data collected by the spacecraft from May 2009 to early January 2010.

"All of Kepler's best capabilities have converged to yield the first solid evidence of a rocky planet orbiting a star other than our sun," said Natalie Batalha, Kepler's deputy science team lead at NASA's Ames Research Center in Moffett Field, Calif., and primary author of a paper on the discovery accepted by the Astrophysical Journal. "The Kepler team made a commitment in 2010 about finding the telltale signatures of small planets in the data, and it's beginning to pay off."

Kepler's ultra-precise photometer measures the tiny decrease in a star's brightness that occurs when a planet crosses in front of it. The size of the planet can be derived from these periodic dips in brightness. The distance between the planet and the star is calculated by measuring the time between successive dips as the planet orbits the star.

Kepler is the first NASA mission capable of finding Earth-size planets in or near the habitable zone, the region in a planetary system where liquid water can exist on the planet's surface. However, since it orbits once every 0.84 days, Kepler-10b is more than 20 times closer to its star than Mercury is to our sun and not in the habitable zone.

Kepler-10 was the first star identified that could potentially harbor a small transiting planet, placing it at the top of the list for ground-based  observations with the W.M. Keck Observatory 10-meter telescope in Hawaii.

Scientists waiting for a signal to confirm Kepler-10b as a planet were not disappointed. Keck was able to measure tiny changes in the star's spectrum, called Doppler shifts, caused by the telltale tug exerted by the orbiting planet on the star.

The discovery of Kepler 10-b is a significant milestone in the search for planets similar to our own," said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington. "Although this planet is not in the habitable zone, the exciting find showcases the kinds of discoveries made possible by the mission and the promise of many more to come," he said.

Knowledge of the planet is only as good as the knowledge of the star it orbits. Because Kepler-10 is one of the brighter stars being targeted by Kepler, scientists were able to detect high frequency variations in the star's brightness generated by stellar oscillations, or starquakes.

This analysis allowed scientists to pin down Kepler-10b's properties.

There is a clear signal in the data arising from light waves that travel within the interior of the star. Kepler Asteroseismic Science Consortium scientists use the information to better understand the star, just as earthquakes are used to learn about Earth's interior structure. As a result of this analysis, Kepler-10 is one of the most well characterized planet-hosting stars in the universe.

That's good news for the team studying Kepler-10b. Accurate stellar properties yield accurate planet properties. In the case of Kepler-10b, the picture that emerges is of a rocky planet with a mass 4.6 times that of Earth and with an average density of 8.8 grams per cubic centimeter -- similar to that of an iron dumbbell.

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5
Jan 11

A high C/O ratio and weak thermal inversion in the atmosphere of exoplanet WASP-12b

Source: Nature


Observations and model spectra for dayside thermal emission of WASP-12b.

Image credits: Nikku Madhusudhan, Joseph Harrington,Kevin B. Stevenson, Sarah Nymeyer, Christopher J. Campo, Peter J. Wheatley, Drake Deming,Jasmina Blecic, Ryan A. Hardy, Nate B. Lust, David R. Anderson, Andrew Collier-Cameron, Christopher B. T. Britt,William C. Bowman,Leslie Hebb, Coel Hellier, Pierre F. L. Maxted, Richard G. West, Don Pollacco

The carbon-to-oxygen ratio (C/O) in a planet provides critical information about its primordial origins and subsequent evolution. A primordial C/O greater than 0.8 causes a carbide-dominated interior, as opposed to the silicate-dominated composition found on Earth1; the atmosphere can also differ from those in the Solar System. The solar C/O is 0.54 . Here we report an analysis of dayside multi-wavelength photometry of the transiting hot-Jupiter WASP-12b that reveals C/O ≥ 1 in its atmosphere. The atmosphere is abundant in CO. It is depleted in water vapour and enhanced in methane, each by more than two orders of magnitude compared to a solar-abundance chemical-equilibrium model at the expected temperatures. We also find that the extremely irradiated atmosphere (T > 2,500 K) of WASP-12b lacks a prominent thermal inversion (or stratosphere) and has very efficient day–night energy circulation. The absence of a strong thermal inversion is in stark contrast to theoretical predictions for the most highly irradiated hot-Jupiter atmosphere. (read Nature)

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