Archive

Archive for October 6, 2011

Solar Orbiter and Euclid Are Next Two Science Missions

October 6, 2011 Leave a comment

The powerful influence of the Sun and the nature of the mysterious ‘dark energy’ motivate ESA’s next two science missions. Solar Orbiter and Euclid were selected today by ESA’s Science Programme Committee for implementation, with launches planned for 2017 and 2019.

These two missions are medium-class missions and are the first in ESA’s Cosmic Vision 2015-2025 Plan.

Full Story: http://www.esa.int/export/esaSC/SEMOZ59U7TG_index_0.html

Global Color Map of Titan, Saturn’s Largest Moon

October 6, 2011 Leave a comment

Credits JPL/NASA/Univ. of Arizona/CNRS/LPGNantes

Credits JPL/NASA/Univ. of Arizona/CNRS/LPGNantes

An international team led by the University of Nantes has pieced together images gathered over six years by the Cassini mission to create a global mosaic of the surface of Titan. The global maps and animations of Saturn’s largest moon are being presented by Stéphane Le Mouélic at the EPSC-DPS Joint Meeting 2011 in Nantes, France on Tuesday 4th October.

The team has compiled all the infrared images acquired by the Visual and Infrared Mapping Spectrometer (VIMS) during Cassini’s first seventy flybys of Titan. Fitting the pieces of the puzzle together is a painstaking task.  The images must be corrected for differences in the illuminating conditions and each image is filtered on a pixel-by-pixel basis to screen out atmospheric distortions. Titan is veiled by a thick, opaque atmosphere composed mainly of nitrogen.  It has clouds of methane and ethane and there is increasing evidence for methane rain. Only a few specific infrared wavelengths can penetrate the cloud and haze to provide a window down to Titan’s surface. An exotic frozen world with many Earth-like geological features has progressively emerged from darkness.

Stéphane Le Mouélic explains: “As Cassini is orbiting Saturn and not Titan, we can observe Titan only once a month on average. The surface of Titan is therefore revealed year after year, as pieces of the puzzle are progressively put together.  Deriving a final map with no seams is challenging due to the effects of the atmosphere – clouds, mist etc. – and due to the changing geometries of observation between each flyby.”

Full Story: http://www.europlanet-eu.org/outreach/index.php?option=com_content&task=view&id=353&Itemid=41

Hyperactive Comet Hartley 2 Has a Split History

October 6, 2011 Leave a comment

The latest analysis of data from NASA’s Deep Impact spacecraft shows that comet 103P/Hartley 2 is hyperactive in terms of the material it spews out, compared to the other comets observed up close to date.  The comet also shows surprising diversity – ice on the comet’s sunlit surface is found in patches that are isolated from areas of dust. In addition, one lobe of the dog-bone shaped comet may have lost much more of the primordial material from the formation of the comet than the other, suggesting that Hartley 2 was originally two comets that came together in a gentle collision. Mike A’Hearn and Lori Feaga will be presenting their findings at the EPSC-DPS Joint Meeting 2011 in Nantes, France.

Deep Impact made its closest encounter of Hartley 2 on 4 November 2010. Over the past year, the science team has been pouring over the data to gain a more detailed understanding of the processes that drive the comet’s activity.

“Hartley 2 works differently from Tempel 1, which was encountered by Deep Impact in 2005 and from Wild 2, which was observed by the Stardust mission.  It ejects a huge amount of material for its size. Halley, which was observed by the Giotto mission lies somewhere in the middle of the spectrum of activity. Since the encounter, we have been able to dig deeper into the data and have provided more evidence of how ice and dust is released from the nucleus,” said A’Hearn, the Principal Investigator of Deep Impact’s mission extension, EPOXI.

Full Story: http://www.europlanet-eu.org/outreach/index.php?option=com_content&task=view&id=355&Itemid=41

Nobel Prize for Physics 2011 Announced

October 6, 2011 Leave a comment

This year’s Nobel Prize for Physics has been awarded to US and Australian pioneers of astrophysics for the discovery of the accelerating expansion of the Universe through observations of distant supernovae.

Saul Perlmutter from the Lawrence Berkeley National Laboratory and University of California, Berkeley, has been awarded half of this year’s prize for his work on the Supernova Cosmology Project, with the other half awarded to Brian P. Schmidt from the Australian National University and Adam G. Riess from the Johns Hopkins University and Space Telescope Science Institute, Baltimore, for their work on the High-z Supernova Search Team.

In response to the announcement, Professor Sir Peter Knight, President of the Institute of Physics, said, “The recipients of today’s award are at the frontier of modern astrophysics and have triggered an enormous amount of research on dark energy.

Full Story: http://www.iop.org/news/11/oct/page_52364.html

NASA’s Kepler Discovers Unusual Multi-Planet System

October 6, 2011 Leave a comment

A team of researchers led by Bill Cochran of The University of Texas at Austin has used NASA’s Kepler spacecraft to discover an unusual multiple-planet system containing a super-Earth and two Neptune-sized planets orbiting in resonance with each other. They will announce the find today in Nantes, France at a joint meeting of the American Astronomical Society’s Division of Planetary Science and the European Planetary Science Conference. The research will be published in a special Kepler issue of The Astrophysical Journal Supplement Series in November.

Cochran’s team is announcing three planets orbiting Kepler-18, a star similar to the Sun. Kepler-18 is just 10 percent larger than the Sun and contains 97 percent of the Sun’s mass. It may host more planets than the three announced today.

The planets are designated b, c, and d. All three planets orbit much closer to Kepler-18 than Mercury does to the Sun. Orbiting closest to Kepler-18 with a 3.5-day period, planet b weighs in at about 6.9 times the mass of Earth, and twice Earth’s size. Planet b is considered a “super-Earth.” Planet c has a mass of about 17 Earths, is about 5.5 times Earth’s size, and orbits Kepler-18 in 7.6 days. Planet d weighs in at 16 Earths, at 7 times Earth’s size, and has a 14.9-day orbit. The masses and sizes of c and d qualify them as low-density “Neptune-class” planets.

Full Story: http://mcdonaldobservatory.org/news/releases/2011/1004.html

The Most Distant & Ancient Supernovae

October 6, 2011 Leave a comment

A team of Japanese, Israeli, and U.S. astronomers used the Subaru Telescope to assemble the largest sample ever found of the most distant exploding stars called supernovae, which emitted their light about ten billion years ago, long before the Earth was formed. The researchers used this sample of ancient supernovae to determine how frequently such explosions of stars occurred in the young universe.

Supernovae have substantial importance in astrophysics. They are nature’s element factories: essentially all of the elements in the periodic table that are heavier than oxygen were formed through nuclear reactions immediately preceding and during these colossal explosions. The explosions fling these elements into interstellar space, where they serve as raw materials for new generations of stars and planets. Thus, the atoms in our bodies, like the calcium atoms in our bones or the iron atoms in our blood, were created in supernovae. By tracking the frequency and types of supernova explosions back through cosmic time, astronomers can reconstruct the universe’s history of element creation, from the plain mix of hydrogen and helium that existed for the first billion years or so after the Big Bang, up to the elemental richness we see today.

However, looking back in time requires looking out to great distances, which means that even these bright explosions are exceedingly faint and difficult to spot. To overcome this obstacle, the team took advantage of a combination of the Subaru Telescope’s assets: the huge light-collecting power of its large 8.2 meter primary mirror; the sharpness of its images, and the wide field of view of its prime focus camera (Suprime-Cam). On four separate occasions, they pointed the telescope toward one single field called the Subaru Deep Field, which spans an area of the sky similar to that covered by the full moon and had previously been studied in great detail by Subaru scientists. By “staring” with the telescope at this single field, they let the faint light from the most distant galaxies and supernovae accumulate over several nights at a time, thus forming a very long and deep exposure of the field. Each of the four observations caught about 40 supernovae in the act of exploding among the 150,000 galaxies in the field. Altogether, the team discovered 150 explosions, including a dozen that rank among the most distant and ancient ever seen.

Full Story: http://www.naoj.org/Pressrelease/2011/10/03/index.html

Crab Pulsar Beams Most Energetic Gamma Rays

October 6, 2011 Leave a comment

Image credits: X-ray: NASA/CXC/SAO/F.Seward; Optical: NASA/ESA/ASU/J.Hester & A.Loll; Infrared: NASA/JPL-Caltech/Univ. Minn./R.Gehrz

Image credits: X-ray: NASA/CXC/SAO/F.Seward; Optical: NASA/ESA/ASU/J.Hester & A.Loll; Infrared: NASA/JPL-Caltech/Univ. Minn./R.Gehrz

Astrophysicists have detected pulsed gamma-ray emission from the Crab pulsar at energies far beyond what current theoretical models of pulsars can explain.

With energies exceeding 100 billion electron-volts (100 GeV), the surprising gamma-ray pulses were detected by the VERITAS telescope array at the Whipple Observatory in Arizona and reported by an international team of scientists in a paper in the October 7 issue ofScience. Corresponding author Nepomuk Otte, a postdoctoral researcher at the University of California, Santa Cruz, said that some researchers had told him he was crazy to even look for pulsar emission in this energy realm.

“It turns out that being persistent and stubborn helps,” Otte said. “These results put new constraints on the mechanism for how the gamma-ray emission is generated.”

Full Story: http://news.ucsc.edu/2011/10/crab-pulsar.html