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viernes, 26 de septiembre de 2014

NASA : NASA Telescopes Find Clear Skies and Water Vapor on Exoplanet

Hola Amigos:  A VUELO DE UN QUINDE EL BLOG-. LA agencia espacial NASA, nos informa del descubrimiento de un exoplaneta llamado: HAT-P-11b, del tamaño de Neptuno, que tiene nubes con vapor de agua, y incluso tiene rocas, el trabajo de descubrimiento ha sido posible utilizando los Telescopios Espaciales: Kepker, Hubble y Spitzer. El exo planeta se encuentra  a 120 años luz de distancia en la constelación de Cisne(Cygnus).
Los resultados de los tres telescopios demuestran que HAT-P-11b está cubierto de vapor de agua, gas hidrógeno y probablemente otras moléculas todavía a ser identificados.
Amigos les invito a leer  la información en detalle abajo adjunta.

Neptune-size planet
A Neptune-size planet with a clear atmosphere is shown crossing in front of its star in this artist's depiction. Such crossings, or transits, are observed by telescopes like NASA's Hubble and Spitzer to glean information about planets' atmospheres.
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Artist's concept of two skies
Scientists were excited to discover clear skies on a relatively small planet, about the size of Neptune, using the combined power of NASA's Hubble, Spitzer and Kepler space telescopes.
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 Feature Link: 
A plot of the transmission spectrum for exoplanet HAT-P-11b
A plot of the transmission spectrum for exoplanet HAT-P-11b, with data from NASA's Kepler, Hubble and Spitzer observatories combined. The results show a robust detection of water absorption in the Hubble data. Transmission spectra of selected atmospheric models are plotted for comparison.
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Astronomers using data from three of NASA's space telescopes -- Hubble, Spitzer and Kepler -- have discovered clear skies and steamy water vapor on a gaseous planet outside our solar system. The planet is about the size of Neptune, making it the smallest planet from which molecules of any kind have been detected.
“This discovery is a significant milepost on the road to eventually analyzing the atmospheric composition of smaller, rocky planets more like Earth,” said John Grunsfeld, assistant administrator of NASA’s Science Mission Directorate in Washington. “Such achievements are only possible today with the combined capabilities of these unique and powerful observatories.”
Clouds in a planet’s atmosphere can block the view to underlying molecules that reveal information about the planet’s composition and history. Finding clear skies on a Neptune-size planet is a good sign that smaller planets might have similarly good visibility.
"When astronomers go observing at night with telescopes, they say 'clear skies' to mean good luck," said Jonathan Fraine of the University of Maryland, College Park, lead author of a new study appearing in Nature. "In this case, we found clear skies on a distant planet. That's lucky for us because it means clouds didn't block our view of water molecules."
The planet, HAT-P-11b, is categorized as an exo-Neptune -- a Neptune-sized planet that orbits the star HAT-P-11. It is located 120 light-years away in the constellation Cygnus. This planet orbits closer to its star than does our Neptune, making one lap roughly every five days. It is a warm world thought to have a rocky core and gaseous atmosphere. Not much else was known about the composition of the planet, or other exo-Neptunes like it, until now.
Part of the challenge in analyzing the atmospheres of planets like this is their size. Larger Jupiter-like planets are easier to see because of their impressive girth and relatively inflated atmospheres. In fact, researchers already have detected water vapor in the atmospheres of those planets. The handful of smaller planets observed previously had proved more difficult to probe partially because they all appeared to be cloudy.
In the new study, astronomers set out to look at the atmosphere of HAT-P-11b, not knowing if its weather would call for clouds. They used Hubble's Wide Field Camera 3, and a technique called transmission spectroscopy, in which a planet is observed as it crosses in front of its parent star. Starlight filters through the rim of the planet's atmosphere; if molecules like water vapor are present, they absorb some of the starlight, leaving distinct signatures in the light that reaches our telescopes.
Using this strategy, Hubble was able to detect water vapor in HAT-P-11b. But before the team could celebrate clear skies on the exo-Neptune, they had to show that starspots -- cooler "freckles" on the face of stars -- were not the real sources of water vapor. Cool starspots on the parent star can contain water vapor that might erroneously appear to be from the planet.
The team turned to Kepler and Spitzer. Kepler had been observing one patch of sky for years, and HAT-P-11b happens to lie in the field. Those visible-light data were combined with targeted Spitzer observations taken at infrared wavelengths. By comparing these observations, the astronomers figured out that the starspots were too hot to have any steam. It was at that point the team could celebrate detecting water vapor on a world unlike any in our solar system. This discovery indicates the planet did not have clouds blocking the view, a hopeful sign that more cloudless planets can be located and analyzed in the future.
"We think that exo-Neptunes may have diverse compositions, which reflect their formation histories," said study co-author Heather Knutson of the California Institute of Technology in Pasadena. "Now with data like these, we can begin to piece together a narrative for the origin of these distant worlds."
The results from all three telescopes demonstrate that HAT-P-11b is blanketed in water vapor, hydrogen gas and likely other yet-to-be-identified molecules. Theorists will be drawing up new models to explain the planet's makeup and origins.
"We are working our way down the line, from hot Jupiters to exo-Neptunes," said Drake Deming, a co-author of the study also from University of Maryland. "We want to expand our knowledge to a diverse range of exoplanets."
The astronomers plan to examine more exo-Neptunes in the future, and hope to apply the same method to super-Earths -- massive, rocky cousins to our home world with up to 10 times the mass. Although our solar system doesn't have a super-Earth, NASA's Kepler mission is finding them in droves around other stars. NASA's James Webb Space Telescope, scheduled to launch in 2018, will search super-Earths for signs of water vapor and other molecules; however, finding signs of oceans and potentially habitable worlds is likely a ways off.
"The work we are doing now is important for future studies of super-Earths and even smaller planets, because we want to be able to pick out in advance the planets with clear atmospheres that will let us detect molecules," said Knutson.
Once again, astronomers will be crossing their fingers for clear skies.
More information about Hubble, Kepler and Spitzer is online at:

Mission Manager Update: C1 data on the ground; C2 underway

The K2 mission has successfully completed its first official set of science observations and the data are on the ground! Campaign 2 observations are now underway.
The team is processing and preparing the data from Campaign 1, which are scheduled to be delivered to the public at the Mikulski Archive for Space Telescopes (MAST) in November. Campaign 1 targets included more than 12,000 stars for exoplanet transit searches, as well as young and old star clusters and galaxies. The latter are being examined for black hole accretion activity or supernovae.

The image is a mosaic of "postage stamp" regions taken during the engineering test run this spring by NASA's Kepler spacecraft operating in the two-wheel K2 mode. Highlighted in the image are two open clusters Messier 35 (top) and NGC 2158 (bottom).
Image Credit: 
NASA Ames/T Barclay/W Stenzel

This past spring the team performed an end-to-end shakedown of spacecraft operations and performance in the new two-wheel K2 mode. While this was primarily an engineering test, science observations were made on approximately 8,000 targets, including the open star cluster Messier 35 and the compact open star cluster NGC 2158, both in the constellation Gemini. Coined "Campaign 0," these data were delivered to the public archive at MAST on Monday, Sept. 8.
The team is now accepting target proposals for Campaigns 4 and 5. The deadline for K2 Cycle-1 Stage-2 Guest Observer proposals is 23:59 p.m. EDT on Sept. 23. For the full schedule of operational milestones see the K2 Mission Timeline.
On Aug. 23, the K2 mission began its second campaign. The Campaign 2 field of view includes the globular star clusters M4 and M80 in the constellation of Scorpius, the very dense star-forming region Rho Ophiuchi, along with 17,000 target stars that can be searched for exoplanets. In mid-October, Comet Siding Spring will be observed for approximately 77 hours as it passes through Kepler's field of view. Many other NASA missions also will be pointed toward the comet. Mars also passes through the field of view, but is too bright to be observed. The campaign is scheduled to conclude on Nov. 11, and will be our first K2 campaign to go from start to finish without a break in the middle.
Meanwhile, the spacecraft continues to deliver robust performance in its two-wheel K2 mode. In early August, a reassessment of the fuel usage increased the expected life of the spacecraft by 25 percent. At the current burn rate, the onboard fuel reserves are now expected to last until late 2017, and perhaps beyond. And last week the spacecraft weathered the effects of a large solar flare without missing a beat!
To learn more about the K2 mission visit the Kepler Science Center website.
Despite ongoing K2 operations, the bulk of the mission science focus remains on finalizing the data processing and products for the formal Kepler mission. Two more releases of the data processing pipeline are scheduled that will include enhancements to increase the sensitivity to small planets in long-period orbits, similar to Earth, and determine their frequency in the galaxy-- Kepler's primary objective.
The following are highlights of recent research using Kepler data that have been accepted by a peer-review journal:
  • Most Sub-Arcsecond Companions of Kepler Exoplanet Candidate Host Stars are Gravitationally Bound (Horch et al., 2014) – This paper finds that about half of the stars hosting planets are actually binary stars. That is, a pair of stars where the planet orbits one of the stars while the other is a bright nighttime spectacle.
  • The Variable Sky of Deep Synoptic Surveys (Ridgway et al., 2014) - Using Kepler light curves to understand how stars and galaxies vary, this paper extends these results to the entire sky to estimate the science yield that will come from the Large Synoptic Survey Telescope and the Gaia space mission, both to undertake all-sky surveys within the next decade.
  • On the Frequency of Potential Venus Analogs from Kepler Data (Kane et al., 2014) – The sensitivity of Kepler data to Earth-sized planets allows us to investigate the frequency of Venus analogs since these planets are similar in size; however, Venus has a runaway greenhouse atmosphere. By using climate models to calculate the distances from a star where a runaway greenhouse would occur, this paper defines a "Venus Zone" for potential Venus analogs and estimates that almost half of sun-like stars harbor an analog to our sister planet.
For the latest Kepler exoplanet and candidate statistics, visit the NASA Exoplanet Archive. The Kepler light curves are available at MAST.
Guillermo Gonzalo Sánchez Achutegui
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