Space & Astronomy

WASHINGTON (Reuters) - European astronomers have spotted what they say is the most Earth-like planet yet outside our solar system, with balmy temperatures that could support water and, potentially, life. They have not directly seen the planet, orbiting a red dwarf star called Gliese 581. But measurements of the star suggest that a planet not much larger than the Earth is pulling on it, the researchers say in a letter to the editor of the journal Astronomy and Astrophysics. "This one is the first one that is at the same time probablyrocky, with water, and in a zone close to the star where the water could exist in liquid form," said Stephane Udry of the Geneva Observatory in Switzerland, who led the study.

"We have estimated that the mean temperature of this super-Earth lies between 0 and 40 degrees Celsius (32 to 104 degrees F), and water would thus be liquid." Most of the 200 or so planets that have been spotted outside this solar system have been gas giants like Jupiter. But this one is small. "Its radius should be only 1.5 times the Earth's radius, and models predict that the planet should be either rocky, like our Earth, or covered with oceans," Udrysaid in a telephone interview.It appears to have a mass five times that of Earth's. The research team includes scientists credited with the first widely accepted discovery of a planet outside our solar system, in 1995. Many teams are looking for planets circling other stars. They are especially looking for those similar to our own, planets that could support life. That means finding water.To view the rest of this article, please visit the source

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Water has been detected for the first time in the atmosphere of a planet outside our Solar System. The planet, known as HD 209458b, is a Jupiter-like gas giant located 150 light-years from Earth in the constellation Pegasus. Other scientists reported in February they were unable to find evidence of water in this planet's atmosphere, as well as in another Jupiter-like planet. Details of the research are published in the Astrophysical Journal. Understanding the distribution of waterin other solar systems is important for understanding whether or not conditions for life are possible Water vapour (or steam) was expected to be present in atmospheres of most known extrasolar planets, even those that orbit more closely to their parent star than Mercury is to our Sun.

For the majority of exoplanets, their close proximity to their parent star has made detecting water and other compounds difficult. The identification reported here takes advantage of the fact that HD209458b, as seen from Earth, passes directly in front of its star every three and half days. As aplanet passes in front of a star, its atmosphere blocks a different amount of starlight at different wavelengths of light. In particular, absorption by water in the atmosphere of a giant planet makes the planet appear larger across a specific part of the infrared spectrum compared to wavelengths in the visible spectrum. To view the rest of the article, please visit the source

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New photographs from the Hubble Space Telescope have revealed extraordinary images of planetary systems being formed. One such image shows a "cosmic jellyfish", a protoplanetary disc hit by particles from a nearby star."An oddarray of 30 newly released images from the Hubble Space Telescope reveal planetary systems in the making.

The blobs and smudges, as astronomers described them, sit in the widely photographed Orion Nebula. Each object is known as a proplyds, or protoplanetary discs, and could be forming planets asyou read this."

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A team of amateur and professional astronomers has discovered a mammoth orb more than 13 times the mass of Jupiter that whips around its parent star in fewer than four days and is considered an "oddball" planet among its exoplanet relatives. The new exoplanet, dubbed XO-3b, was described here at a meeting of the American Astronomical Society. The discovery came out of the XO Project, a collaboration between amateur and professional astronomers. "Of the 200-plus exoplanets found so far, XO-3b is an oddity in several respects," said XO Project director Peter McCullough, an astronomer atthe Space Telescope Science Institute in Baltimore.

For one, it's the largest and most massive planet found in such a tight orbit around its parent star. Secondly, with such a close proximity between the planet and star, astronomers would expect a circular orbit as the parent star's gravity tugs and shapes the orbit. But XO-3b treks along an elliptical orbit. And during every orbit, XO-3b passes in front of its star, making it a "transiting planet," of which just a few dozen have been identified.The finding also stirs up an already frothy debate concerning the boundary between brown dwarfs and massive planets. "We are intrigued that its mass is on the boundary between planetsand 'brown dwarfs,'" said Christopher Johns-Krull, an astronomer at Rice University. "There's still a lively debate among astronomers about how to classify brown dwarfs." Brown dwarfs are too massive to be considered planets, yet they don't meet the "Sumo-weight" requirements for hydrogen fusion (about 80 Jupiters) so they fall short of being stars. The new object's mass is right on the boundary where brown-dwarf status begins, a mass requirement for the burning of deuterium, or heavy hydrogen.To view the rest of this article, please visit the source

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