Fwd: Re: Yahoo! News Story - Exoplanet Atmospheres Detected from Earth - Yahoo! News
(OGLE = Optical Gravitational Lensing Experiment, a Polish astronomical project based at Warsaw University
"...chiefly concerned with discovering dark matter using the microlensing technique."
Declination -29 32' 21.2
In Sagittarius, near the Scorpius and Ophiuchus borders, between Gamma Sagittarii (Alnasl) and Rho Ophiuchi.
29 Sagittarius 24 (2000).
(TrES = Transatlantic Exoplanet Survey
RA 17h 52m 07s
Declination +37 32′ 46″
In Hercules, near Pi and 69 Herculis.
26 Sagittarius 55 (2000).
Mark A. Holmes
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> > Exoplanet Atmospheres Detected from Earth - Yahoo! News
> Exoplanet Atmospheres Detected from Earth
> Andrea Thompson
> Senior Writer
> SPACE.com andrea Thompson
> Wed Jan 14, 3:27 pm ET
> Two independent groups of astronomers have detected the atmospheres of
> planets around other stars from ground-based telescopes.
> Previous observations of the atmospheres of extrasolar planets had
> been made almost entirely by space-based instruments, such as the
> Hubble and Spitzer space telescopes, although another team last year
> detected the signature of sodium in an exoplanet atmosphere.
> To date, astronomers have detected several key gases in planets'
> atmospheres, including:
> * Carbon dioxide a potential sign of life, though the planet
> where the gas was observed was too hot to be habitable.
> * Water vapor a key molecule required to support life as we know it.
> * Silicates (combinations of silicon and oxygen) components of
> most rocks on Earth, likely in the form of clouds of dust grains on
> massive exoplanets.
> * Sodium detected in 2001, it marked the first space-based
> observation of an exoplanet atmosphere.
> Ground-based detection is becoming a priority as Hubble ages and
> Spitzer is set to run out of cryogens, which keep its instruments cool
> enough to detect infrared radiation (heat), limiting its abilities.
> "Others have tried to detect planetary atmospheres from Earth, but to
> no avail," said the co-author of one of the new studies, Mercedes
> López-Morales of the Carnegie Institution in Washington, D.C. "We hit
> it right two nights last summer."
> López-Morales and her team observed the planet OGLE-TR056b, a
> so-called "hot Jupiter."
> Hot Jupiters
> Hot Jupiters are massive gaseous planets that orbit very close to
> their stars, whipping around them in two to three days. Their
> proximity to their parent stars indicates the planets are hot enough
> to emit radiation in the optical and near-infrared wavelengths and
> that their radiation is detectable from Earth.
> But OGLE-TR056b is faint, sitting about 5,000 light-years away and in
> a crowded part of the night sky, located in the direction of the
> center of our galaxy from the Earth's perspective. So López-Morales
> and her colleagues used the European Southern Observatory's Very Large
> Telescope (on July 2) and Carnegie's Magellan-Baade telescope (on Aug.
> 3). Both telescopes are located in Chile.
> Only about one out of every 3,000 photons from the star comes from the
> planet itself. The rest is from the overwhelming light of the star. So
> astronomers wait until the planet is eclipsed as it orbits behind the
> star (from the Earth's perspective), which allows for separation of
> the emissions of the planet from those of the star.
> "The planet is glowing red-hot like a kitchen stove burner, but we had
> to know precisely when the eclipse was going to happen and measure the
> stellar flux very accurately so it could be removed to reveal the
> planet's thermal emissions," said lead author of the study David Sing
> of Institut d'Astrophysique de Paris.
> Real hot
> The team took more than 600 images of OGLE-TR056b with both
> telescopes. The planet is hotter than any detected by Spitzer so far
> its atmosphere is more than 4,400 degrees Fahrenheit (2,400 degrees
> The observations also indicated that the planet has little to no cloud
> cover and a static atmosphere with little circulation, López-Morales
> told SPACE.com in an email.
> Their work will be detailed in an upcoming issue of the journal
> Astronomy & Astrophysics.
> In the same issue of the journal, a Dutch team will explain their
> detection of the thermal emission in the near-infrared of another
> exoplanet dubbed TrES-3b. Its atmosphere registered at about 3,000 F
> (1,700 C).
> --- End forwarded message ---