Astronews Daily (2455476)

October 6, 2010 12:04 by scibuff

Top Stories

Saturn’s Rings Formed from Large Moon’s Destruction – The formation of Saturn‘s rings has been one of the classical if not eternal questions in astronomy. But one researcher has provided a provocative new theory to answer that question. Robin Canup from the Southwest Research Institute has uncovered evidence that the rings came from a large, Titan-sized moon that was destroyed as it spiraled into a young Saturn. –Nancy Atkinson / Universe Today

Trojans May Yet Rain Down – In the past decade Neptunian Trojans have been discovered. By the end of this summer, six have been confirmed. Yet despite this small sample, these objects have some unexpected properties and may outnumber the number of asteroids in the main belt by an order of magnitude. – Jon Voisey / Universe Today

China’s Chang’E-2 in Lunar Orbit – Chang’E-2 was captured by the lunar gravity fields after five days of spaceflight. The Chinese space probe has become as lunar orbiter at 11:40, 6th Oct (Beijing local time), according to Yong-Chun Zheng of the National Astronomical Observatories, Chinese Academy of Sciences. –Spaceports

International Astronautical Congress – Prague 2010 Highlights – I attended the International Astronautical Congress last week in Prague, Czech Republic. I attended the Vancouver Congress years ago, but as an exhibit staffer, not a presenter. This was my first time to present papers. Quite an experience. – Beth Beck

[more stories]


The Soyuz TMA-01M spacecraft and its booster were moved to its launch pad on a railcar Oct. 5 for final preparations prior to its launch Oct. 8 to the International Space Station. The Soyuz will carry Expedition 25 Soyuz Commander Alexander Kaleri, NASA Flight Engineer Scott Kelly and Russian Flight Engineer Oleg Skripochka to the orbiting laboratory. The trio will spend six months on the complex, joining station Commander Doug Wheelock and Flight Engineers Fyodor Yurchikhin and Shannon Walker, who have been in orbit since June. - Credit: NASA TV



Monoceros R2

Monoceros R2

103P/Hartley 2

103P/Hartley 2

North American and Pelican

North American and Pelican

Seattle, WA

Seattle, WA


Gallery Pick of the Day

G327.1-1.1: Pushing the Envelope

G327.1-1.1: Pushing the Envelope - G327 is the aftermath of a star that exploded as a supernova. X-rays are blue, radio data are red and yellow, and infrared data show the stars in the field - Credit: X-ray: NASA/CXC/SAO/T.Temim et al. and ESA/XMM-Newton Radio: SIFA/MOST and CSIRO/ATNF/ATCA; Infrared: UMass/IPAC-Caltech/NASA/NSF/2MASS

The photo above is “Pick of the Day” from one of the three galleries: Astronomy Gallery, Space Shuttle Gallery and Space Station Gallery.

Triton’s atmosphere more mysterious than thought

April 7, 2010 10:57 by scibuff

The first ever infrared analysis of the atmosphere of Neptune’s moon Triton revealed the presence carbon monoxide and methane. As summer hit the moon’s southern hemisphere, observations made at the Very Large Telescope (VLT) based at the European Southern Observatory (ESO) showed the thin atmosphere to vary with seasons.

Artist’s impression of Triton

Artist’s impression of how Triton, Neptune’s largest moon, might look from high above its surface. The distant Sun appears at the upper-left and the blue crescent of Neptune right of center - Credit: ESO/L. Calçada

“We have found real evidence that the Sun still makes its presence felt on Triton, even from so far away. This icy moon actually has seasons just as we do on Earth, but they change far more slowly,” says Emmanuel Lellouch, the lead author of the paper reporting these results in Astronomy & Astrophysics.

On Triton, where the average surface temperature is about minus 235 degrees Celsius, it is currently summer in the southern hemisphere and winter in the northern. As Triton’s southern hemisphere warms up, a thin layer of frozen nitrogen, methane, and carbon monoxide on Triton’s surface sublimates into gas, thickening the icy atmosphere as the season progresses during Neptune’s 165-year orbit around the Sun. A season on Triton lasts a little over 40 years, and Triton passed the southern summer solstice in 2000.

Based on the amount of gas measured, Lellouch and his colleagues estimate that Triton’s atmospheric pressure may have risen by a factor of four compared to the measurements made by Voyager 2 in 1989, when it was still spring on the giant moon.

Carbon monoxide was known to be present as ice on the surface, but Lellouch and his team discovered that Triton’s upper surface layer is enriched with carbon monoxide ice by about a factor of ten compared to the deeper layers, and that it is this upper “film” that feeds the atmosphere. While the majority of Triton’s atmosphere is nitrogen (much like on Earth), the methane in the atmosphere, first detected by Voyager 2, and only now confirmed in this study from Earth, plays an important role as well.

Triton from Voyager 2

Voyager 2 raw image of Neptune's satellite Triton taken from roughly 500,000 km. Evidence of complex surface features can be seen from this distance - Credit: NASA

Of Neptune’s 13 moons, Triton is by far the largest, and, at 2700 kilometers in diameter (or three quarters the Earth’s Moon), is the seventh largest moon in the whole Solar System. Since its discovery in 1846, Triton has fascinated astronomers thanks to its geologic activity, the many different types of surface ices, such as frozen nitrogen as well as water and dry ice (frozen carbon dioxide), and its unique retrograde motion.

Observing the atmosphere of Triton, which is roughly 30 times further from the Sun than Earth, is not easy. In the 1980s, astronomers theorised that the atmosphere on Neptune’s moon might be as thick as that of Mars (7 millibars). It wasn’t until Voyager 2 passed the planet in 1989 that the atmosphere of nitrogen and methane, at an actual pressure of 14 microbars, 70 000 times less dense than the atmosphere on Earth, was measured. Since then, ground-based observations have been limited. Observations of stellar occultations (a phenomenon that occurs when a Solar System body passes in front of a star and blocks its light) indicated that Triton’s surface pressure was increasing in the 1990’s. It took the development of the Cryogenic High-Resolution Infrared Echelle Spectrograph (CRIRES) at the Very Large Telescope (VLT) to provide the team the chance to perform a far more detailed study of Triton’s atmosphere.

Source: ESO