NASA's Spitzer detects comet storm in nearby solar system

ScienceDaily (Oct. 19, 2011) — 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," which may have brought water and other life-forming ingredients to Earth.

During this epoch, comets and other frosty objects that were flung from the outer solar system pummeled the inner planets. The barrage scarred our moon and produced large amounts of dust.

Now Spitzer has spotted a band of dust around a nearby bright star in the northern sky called Eta Corvi that strongly matches the contents of an obliterated giant comet. This dust is located close enough to Eta Corvi that Earth-like worlds could exist, suggesting a collision took place between a planet and one or more comets. The Eta Corvi system is approximately one billion years old, which researchers think is about the right age for such a hailstorm.

"We believe we have direct evidence for an ongoing Late Heavy Bombardment in the nearby star system Eta Corvi, occurring about the same time as in our solar system," said Carey Lisse, senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., and lead author of a paper detailing the findings. The findings will be published in the Astrophysical Journal. Lisse presented the results at the Signposts of Planets meeting at NASA's Goddard Space Flight Center in Greenbelt, Md., on Oct. 19.

Astronomers used Spitzer's infrared detectors to analyze the light coming from the dust around Eta Corvi. Certain chemical fingerprints were observed, including water ice, organics and rock, which indicate a giant comet source.

The light signature emitted by the dust around Eta Corvi also resembles the Almahata Sitta meteorite, which fell to Earth in fragments across Sudan in 2008. The similarities between the meteorite and the object obliterated in Eta Corvi imply a common birthplace in their respective solar systems.

A second, more massive ring of colder dust located at the far edge of the Eta Corvi system seems like the proper environment for a reservoir of cometary bodies. This bright ring, discovered in 2005, looms at about 150 times the distance from Eta Corvi as Earth is from the sun. Our solar system has a similar region, known as the Kuiper Belt, where icy and rocky leftovers from planet formation linger. The new Spitzer data suggest that the Almahata Sitta meteorite may have originated in our own Kuiper Belt.

The Kuiper Belt was home to a vastly greater number of these frozen bodies, collectively dubbed Kuiper Belt objects. About 4 billion years ago, some 600 million years after our solar system formed, scientists think the Kuiper Belt was disturbed by a migration of the gas-giant planets Jupiter and Saturn. This jarring shift in the solar system's gravitational balance scattered the icy bodies in the Kuiper Belt, flinging the vast majority into interstellar space and producing cold dust in the belt. Some Kuiper Belt objects, however, were set on paths that crossed the orbits of the inner planets.

The resulting bombardment of comets lasted until 3.8 billion years ago. After comets impacted the side of the moon that faces Earth, magma seeped out of the lunar crust, eventually cooling into dark "seas," or maria. When viewed against the lighter surrounding areas of the lunar surface, those seas form the distinctive "Man in the Moon" visage. Comets also struck Earth or incinerated in the atmosphere, and are thought to have deposited water and carbon on our planet. This period of impacts might have helped life form by delivering its crucial ingredients.

"We think the Eta Corvi system should be studied in detail to learn more about the rain of impacting comets and other objects that may have started life on our own planet," Lisse said.

NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the Spitzer mission for the agency's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer .

Recommend this story on Facebook, Twitter,
and Google +1:

Other bookmarking and sharing tools:

Story Source:

The above story is reprinted from materials provided by NASA/Jet Propulsion Laboratory.

Note: ScienceDaily reserves the right to edit materials for content and length. For further information, please contact the source cited above.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

NASA's Spitzer finds distant galaxies grazed on gas

ScienceDaily (July 1, 2011) — Galaxies once thought of as voracious tigers are more like grazing cows, according to a new study using NASA's Spitzer Space Telescope.

Astronomers have discovered that galaxies in the distant, early universe continuously ingested their star-making fuel over long periods of time. This goes against previous theories that the galaxies devoured their fuel in quick bursts after run-ins with other galaxies.

"Our study shows the merging of massive galaxies was not the dominant method of galaxy growth in the distant universe," said Ranga-Ram Chary of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena, Calif. "We're finding this type of galactic cannibalism was rare. Instead, we are seeing evidence for a mechanism of galaxy growth in which a typical galaxy fed itself through a steady stream of gas, making stars at a much faster rate than previously thought."

Chary is the principal investigator of the research, appearing in the Aug. 1 issue of the Astrophysical Journal. According to his findings, these grazing galaxies fed steadily over periods of hundreds of millions of years and created an unusual amount of plump stars, up to 100 times the mass of our sun.

"This is the first time that we have identified galaxies that supersized themselves by grazing," said Hyunjin Shim, also of the Spitzer Science Center and lead author of the paper. "They have many more massive stars than our Milky Way galaxy."

Galaxies like our Milky Way are giant collections of stars, gas and dust. They grow in size by feeding off gas and converting it to new stars. A long-standing question in astronomy is: Where did distant galaxies that formed billions of years ago acquire this stellar fuel? The most favored theory was that galaxies grew by merging with other galaxies, feeding off gas stirred up in the collisions.

Chary and his team addressed this question by using Spitzer to survey more than 70 remote galaxies that existed 1 to 2 billion years after the Big Bang (our universe is approximately 13.7 billion years old). To their surprise, these galaxies were blazing with what is called H alpha, which is radiation from hydrogen gas that has been hit with ultraviolet light from stars. High levels of H alpha indicate stars are forming vigorously. Seventy percent of the surveyed galaxies show strong signs of H alpha. By contrast, only 0.1 percent of galaxies in our local universe possess this signature.

Previous studies using ultraviolet-light telescopes found about six times less star formation than Spitzer, which sees infrared light. Scientists think this may be due to large amounts of obscuring dust, through which infrared light can sneak. Spitzer opened a new window onto the galaxies by taking very long-exposure infrared images of a patch of sky called the GOODS fields, for Great Observatories Origins Deep Survey.

Further analyses showed that these galaxies furiously formed stars up to 100 times faster than the current star-formation rate of our Milky Way. What's more, the star formation took place over a long period of time, hundreds of millions of years. This tells astronomers that the galaxies did not grow due to mergers, or collisions, which happen on shorter timescales. While such smash-ups are common in the universe -- for example, our Milky Way will merge with the Andromeda galaxy in about 5 billion years -- the new study shows that large mergers were not the main cause of galaxy growth. Instead, the results show that distant, giant galaxies bulked up by feeding off a steady supply of gas that probably streamed in from filaments of dark matter.

Chary said, "If you could visit a planet in one of these galaxies, the sky would be a crazy place, with tons of bright stars, and fairly frequent supernova explosions."

NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the Spitzer Space Telescope mission for the agency's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech. Caltech manages JPL for NASA.

For more information about Spitzer, visit http://www.nasa.gov/spitzer and http://spitzer.caltech.edu/ .

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by NASA/Jet Propulsion Laboratory.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Green ring fit for a superhero: Spitzer Space Telescope spies powerful light of giant 'O' stars

ScienceDaily (June 19, 2011) — This glowing emerald nebula seen by NASA's Spitzer Space Telescope is reminiscent of the glowing ring wielded by the superhero Green Lantern. In the comic books, the diminutive Guardians of the Planet "Oa" forged his power ring, but astronomers believe rings like this are actually sculpted by the powerful light of giant "O" stars. O stars are the most massive type of star known to exist.

Named RCW 120 by astronomers, this region of hot gas and glowing dust can be found in the murky clouds encircled by the tail of the constellation Scorpius. The green ring of dust is actually glowing in infrared colors that our eyes cannot see, but show up brightly when viewed by Spitzer's infrared detectors. At the center of this ring are a couple of giant stars whose intense ultraviolet light carved out the bubble, though they blend in with the other stars when viewed in infrared.

Rings like this are so common in Spitzer's observations that astronomers have even enlisted the help of the public to help find and catalog them all. Anyone interested in joining the search as a citizen scientist can visit "The Milky Way Project," part of the "Zooniverse" of public astronomy projects, at http://www.milkywayproject.org/ .

The flat plane of our galaxy is located toward the bottom of the picture, and the ring is slightly above the plane. The green haze seen at the bottom of the image is the diffuse glow of dust from the galactic plane.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by NASA's Jet Propulsion Laboratory.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

Number of stories in archives: 104,440
Post this page to your favorite social bookmarking site:Include this item in your blog or web site:Cite this article in your essay, paper, or report:Email this page's link to a friend or colleague: document.write(unescape("%3Cscript src='" + (document.location.protocol == "https:" ? "https://sb" : "http://b") + ".scorecardresearch.com/beacon.js' %3E%3C/script%3E")); COMSCORE.beacon({ c1:2, c2:1000004, c3:"", c4:"", c5:"", c6:"", c15:"" });

View the original article here

Green ring fit for a superhero: Spitzer Space Telescope spies powerful light of giant 'O' stars

ScienceDaily (June 19, 2011) — This glowing emerald nebula seen by NASA's Spitzer Space Telescope is reminiscent of the glowing ring wielded by the superhero Green Lantern. In the comic books, the diminutive Guardians of the Planet "Oa" forged his power ring, but astronomers believe rings like this are actually sculpted by the powerful light of giant "O" stars. O stars are the most massive type of star known to exist.

Named RCW 120 by astronomers, this region of hot gas and glowing dust can be found in the murky clouds encircled by the tail of the constellation Scorpius. The green ring of dust is actually glowing in infrared colors that our eyes cannot see, but show up brightly when viewed by Spitzer's infrared detectors. At the center of this ring are a couple of giant stars whose intense ultraviolet light carved out the bubble, though they blend in with the other stars when viewed in infrared.

Rings like this are so common in Spitzer's observations that astronomers have even enlisted the help of the public to help find and catalog them all. Anyone interested in joining the search as a citizen scientist can visit "The Milky Way Project," part of the "Zooniverse" of public astronomy projects, at http://www.milkywayproject.org/ .

The flat plane of our galaxy is located toward the bottom of the picture, and the ring is slightly above the plane. The green haze seen at the bottom of the image is the diffuse glow of dust from the galactic plane.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by NASA's Jet Propulsion Laboratory.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Spitzer detects shadow of 'super-Earth' in front of nearby star

ScienceDaily (May 5, 2011) — NASA's Spitzer Space Telescope has detected the crossing of a solid planet  in front of a star located at only 42 light-years in the constellation Cancer. Thanks to this detection, astronomers know that this "super-Earth" measures 2.1 times the size of our Earth. This is the smallest exoplanet detected in the neighborhood of our Sun.

The discovery is based on data acquired by the Spitzer spacecraft last January. The data allowed astronomers to detect the "transit" of the planet, i.e. the tiny decrease of the star's brightness occurring when the planet passes in front of it.

"So far, the exquisite capabilities of Spitzer have been extensively used to study known transiting exoplanets, all of them being giant planets similar to Jupiter or Neptune. For the first time, Spitzer is used to detect the transit of a super-Earth, a solid planet not much larger than our own Earth," says Michaël Gillon from University of Liège (Belgium), the leader of the team that made this detection. "Thanks to the high-precision of Spitzer, we now know the nature of this planet, and, interestingly, it is very different from all the planets of our solar System."

The planet name is 55 Cancri e. With 8 times the mass of the Earth, for a size 2.1 larger, it is simply too big to be purely rocky, meaning that it must have a significant fraction of ice, the favored composition being a massive shell of water ice on top of a rocky nucleus. "We could call this planet a 'naked Neptune', as it is very similar to Neptune except that it has no gazeous envelope of hydrogen above its ice shell," says Brice-Olivier Demory from the Massachusets Institute of Technology (MIT), the first author of the paper describing the discovery. "But the analogy with Neptune stops here: 55 Cancri e is more than 1900 times closer to its star than Neptune to the Sun. At such a short distance, the planet is literally baked by the intense stellar radiation."

The host star itself  has a particularity that makes this planet very interesting for astronomers. It is not a dim star that can only be seen with a telescope, but a very bright star of the solar neighborhood (42 light-years), visible even for the human eye. "The brightness of the host star will make possible the first throrough characterization of a solid planet orbiting a star similar to our Sun," says Gillon. "If this planet has an atmosphere, we will be able to study it details, unlike the other solid planets found  so far around farer and dimmer stars."

Interestingly, the study of the atmosphere of 55 Cancri e has maybe already begun. Indeed, another team of astronomers indepently announced April 29, the detection of the transits of the same planet with another space telescope, MOST. This team observed at a different wavelength than Spitzer, and their measured planet radius is 1.3 times smaller. "A possible explanation for this discrepancy would be the presence of a huge molecular enveloppe outgassed by the planet, making the planet appear larger for Spitzer," says Demory. "Only new measurements will tell us."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Liège.

Journal References:

B.-O. Demory, M. Gillon, D. Deming, D. Valencia, S. Seager, B. Benneke, C. Lovis, P. Cubillos, J. Harrington, K. B. Stevenson, M. Mayor, F. Pepe, D. Queloz, D. Segransan, S. Udry. Detection of a transit of the super-Earth 55 Cnc e with Warm Spitzer. Astronomy & Astrophysics, 2011; (submitted) [link]Joshua N. Winn, Jaymie M. Matthews, Rebekah I. Dawson, Daniel Fabrycky, Matthew J. Holman, Thomas Kallinger, Rainer Kuschnig, Dimitar Sasselov, Diana Dragomir, David B. Guenther, Anthony F.J. Moffat, Jason F. Rowe, Slavek Rucinski, Werner W. Weiss. A Super-Earth Transiting a Naked-Eye Star. Astrophysical Journal Letters, 2011; (submitted) [link]

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Spitzer detects shadow of 'super-Earth' in front of nearby star

ScienceDaily (May 5, 2011) — NASA's Spitzer Space Telescope has detected the crossing of a solid planet  in front of a star located at only 42 light-years in the constellation Cancer. Thanks to this detection, astronomers know that this "super-Earth" measures 2.1 times the size of our Earth. This is the smallest exoplanet detected in the neighborhood of our Sun.

The discovery is based on data acquired by the Spitzer spacecraft last January. The data allowed astronomers to detect the "transit" of the planet, i.e. the tiny decrease of the star's brightness occurring when the planet passes in front of it.

"So far, the exquisite capabilities of Spitzer have been extensively used to study known transiting exoplanets, all of them being giant planets similar to Jupiter or Neptune. For the first time, Spitzer is used to detect the transit of a super-Earth, a solid planet not much larger than our own Earth," says Michaël Gillon from University of Liège (Belgium), the leader of the team that made this detection. "Thanks to the high-precision of Spitzer, we now know the nature of this planet, and, interestingly, it is very different from all the planets of our solar System."

The planet name is 55 Cancri e. With 8 times the mass of the Earth, for a size 2.1 larger, it is simply too big to be purely rocky, meaning that it must have a significant fraction of ice, the favored composition being a massive shell of water ice on top of a rocky nucleus. "We could call this planet a 'naked Neptune', as it is very similar to Neptune except that it has no gazeous envelope of hydrogen above its ice shell," says Brice-Olivier Demory from the Massachusets Institute of Technology (MIT), the first author of the paper describing the discovery. "But the analogy with Neptune stops here: 55 Cancri e is more than 1900 times closer to its star than Neptune to the Sun. At such a short distance, the planet is literally baked by the intense stellar radiation."

The host star itself  has a particularity that makes this planet very interesting for astronomers. It is not a dim star that can only be seen with a telescope, but a very bright star of the solar neighborhood (42 light-years), visible even for the human eye. "The brightness of the host star will make possible the first throrough characterization of a solid planet orbiting a star similar to our Sun," says Gillon. "If this planet has an atmosphere, we will be able to study it details, unlike the other solid planets found  so far around farer and dimmer stars."

Interestingly, the study of the atmosphere of 55 Cancri e has maybe already begun. Indeed, another team of astronomers indepently announced April 29, the detection of the transits of the same planet with another space telescope, MOST. This team observed at a different wavelength than Spitzer, and their measured planet radius is 1.3 times smaller. "A possible explanation for this discrepancy would be the presence of a huge molecular enveloppe outgassed by the planet, making the planet appear larger for Spitzer," says Demory. "Only new measurements will tell us."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Liège.

Journal References:

B.-O. Demory, M. Gillon, D. Deming, D. Valencia, S. Seager, B. Benneke, C. Lovis, P. Cubillos, J. Harrington, K. B. Stevenson, M. Mayor, F. Pepe, D. Queloz, D. Segransan, S. Udry. Detection of a transit of the super-Earth 55 Cnc e with Warm Spitzer. Astronomy & Astrophysics, 2011; (submitted) [link]Joshua N. Winn, Jaymie M. Matthews, Rebekah I. Dawson, Daniel Fabrycky, Matthew J. Holman, Thomas Kallinger, Rainer Kuschnig, Dimitar Sasselov, Diana Dragomir, David B. Guenther, Anthony F.J. Moffat, Jason F. Rowe, Slavek Rucinski, Werner W. Weiss. A Super-Earth Transiting a Naked-Eye Star. Astrophysical Journal Letters, 2011; (submitted) [link]

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here