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Very-High-Energy Gamma Rays from Crab Pulsar

October 10, 2011 Leave a comment

Credit: Chandra X-ray Observatory, NASA/CXC/SAO/F. Seward.

Credit: Chandra X-ray Observatory, NASA/CXC/SAO/F. Seward.

Iowa State University astrophysicists are part of an international team that unexpectedly discovered very-high-energy gamma rays from the already well-known Crab pulsar star.

The team’s findings are published in the Oct. 7 issue of the journal Science.

“This is the first time very-high-energy gamma rays have been detected from a pulsar — a rapidly spinning neutron star about the size of the city of Ames but with a mass greater than that of the Sun,” said Frank Krennrich, an Iowa State professor of physics and astronomy and a co-author of the paper.

The discovery was the work of three post-doctoral researchers — including Martin Schroedter, who left Iowa State last year for a position at the Fred Lawrence Whipple Observatory near Amado, Ariz.

The researchers’ finding was a surprise, said Amanda Weinstein, an Iowa State assistant professor of physics and astronomy. Astrophysicists started looking for very-high-energy gamma rays from the Crab pulsar decades ago and had never found them with energies greater than 25 billion electron volts.

Full Story: http://www.news.iastate.edu/news/2011/oct/gammarays

NASA Developing Instruments For New Solar Orbiter Mission

October 10, 2011 Leave a comment

NASA will begin development and testing of two science instruments, in cooperation with the European Space Agency (ESA), to be placed on ESA’s newly selected Solar Orbiter mission. The spacecraft will study the sun from a closer distance than any previous mission.

At its closest approach, the European-led project will operate approximately 21 million miles from the sun’s surface, near the orbit of Mercury, roughly 25 percent of the distance from the sun to the Earth. This unique vantage point will enhance the ability to forecast space weather.

Space weather produces disturbances in electromagnetic fields on Earth that can induce extreme currents in wires, disrupt power lines and cause widespread blackouts. These sun storms can interfere with communications between ground controllers and satellites and with airplane pilots flying near Earth’s poles. Radio noise from the storms also can disrupt cell phone service.

Full Story: http://www.nasa.gov/home/hqnews/2011/oct/HQ_11-339_solar_orbiter_investigations.html

Series of Bumps Knocked Uranus Sideways

October 10, 2011 Leave a comment

Credit: Lawrence Sromovsky, (Univ. Wisconsin-Madison), Keck Observatory.

Credit: Lawrence Sromovsky, (Univ. Wisconsin-Madison), Keck Observatory.

Uranus’s highly tilted axis makes it something of an oddball in our Solar System. The accepted wisdom is that Uranus was knocked on its side by a single large impact, but new research to be presented on Thursday 6th October at the EPSC-DPS Joint Meeting in Nantes rewrites our theories of how Uranus became so tilted and also solves fresh mysteries about the position and orbits of its moons. By using simulations of planetary formation and collisions, it appears that early in its life Uranus experienced a succession of small punches instead of a single knock-out blow. This research has important ramifications on our theories of giant planet formation.

Uranus is unusual in that its spin axis is inclined by 98 degrees compared to its orbital plane around the Sun. This is far more pronounced than other planets, such as Jupiter (3 degrees), Earth (23 degrees), or Saturn and Neptune (29 degrees). Uranus is, in effect, spinning on its side.

The generally accepted theory is that in the past a body a few times more massive than the Earth collided with Uranus, knocking the planet on its side. There is, however, one significant flaw in this notion: the moons of Uranus should have been left orbiting in their original angles, but they too lie at almost exactly 98 degrees.

This long-standing mystery has been solved by an international team of scientists led by Alessandro Morbidelli (Observatoire de la Cote d’Azur in Nice, France), who will be presenting his group’s research on Thursday 6th October at the EPSC-DPS Joint Meeting in Nantes, France.

Full Story: http://www.europlanet-eu.org/outreach/index.php?option=com_content&task=view&id=359&Itemid=41

Elusive Planets Found in Decade-Old Hubble Data

October 10, 2011 Leave a comment

In a painstaking re-analysis of Hubble Space Telescope images from 1998, astronomers have found visual evidence for two extrasolar planets that went undetected back then.

Finding these hidden gems in the Hubble archive gives astronomers an invaluable time machine for comparing much earlier planet orbital motion data to more recent observations. It also demonstrates a novel approach for planet hunting in archival Hubble data.

Four giant planets are known to orbit the young, massive star HR 8799, which is 130 light-years away. In 2007 and 2008 the first three planets were discovered in near-infrared ground-based images taken with the W.M. Keck Observatory and the Gemini North telescope by Christian Marois of the National Research Council in Canada and his team. Marois and his colleagues then uncovered the fourth and innermost planet in 2010. This is the only multiple-exoplanet system for which astronomers have obtained direct snapshots.

In 2009 David Lafreniere of the University of Montreal recovered hidden exoplanet data in Hubble images of HR 8799 taken in 1998 with the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). He identified the position of the outermost planet known to orbit the star. This first demonstrated the power of a new data-processing technique for retrieving faint planets buried in the glow of the central star.

Full Story: http://hubblesite.org/newscenter/archive/releases/2011/29/full/

Secrets of Asteroid Minerva & Its 2 Moons

October 10, 2011 Leave a comment

Credit: D Futselaar.

Credit: D Futselaar.

Since the discovery of its two moons, the triple asteroid Minerva has been the focus of space and ground-based telescope studies that have attempted to unravel the secrets of this intriguing system. A multiple-telescope campaign has now revealed that Minerva is unusually round for an asteroid, and has a possibly unique structure.

The campaign to “weigh” the asteroid and derive its density and other characteristics was undertaken by an international team of planetary astronomers led by Franck Marchis, researcher at the Carl Sagan Center of the SETI Institute.  Marchis will report on their findings at the EPSC-DPS Joint Meeting 2011 in Nantes, France,

Minerva is the fourth asteroid located in the main-belt known to possess two moons. With a diameter of 156 km and two tiny 5-km size moons, this triple system orbits around the Sun between Mars and Jupiter. The two moons were discovered in 2009 using the Keck II telescope by members of this team. Other triple asteroids in the main-belt are 87 Sylvia (triplicity discovered in 2005), 45 Eugenia (2006), and 216 Kleopatra (2008). Marchis and his team were involved in the discovery of the triplicity of these asteroids and the follow-up studies.

Full Story: http://www.europlanet-eu.org/outreach/index.php?option=com_content&task=view&id=358&Itemid=41

Venus Has an Ozone Layer Too

October 10, 2011 Leave a comment

ESA’s Venus Express spacecraft has discovered an ozone layer high in the atmosphere of Venus. Comparing its properties with those of the equivalent layers on Earth and Mars will help astronomers refine their searches for life on other planets. The results are being presented today at the Joint Meeting of the European Planetary Science Congress and the American Astronomical Society’s Division for Planetary Sciences.

Venus Express made the discovery while watching stars seen right at the edge of the planet set through its atmosphere.  Its SPICAV instrument analysed the starlight, looking for the characteristic fingerprints of gases in the atmosphere as they absorbed light at specific wavelengths.

The ozone was detectable because it absorbed some of the ultraviolet from the starlight.

Full Story: http://www.europlanet-eu.org/outreach/index.php?option=com_content&task=view&id=357&Itemid=41

Astronomy & Geophysics Bring Women into Science

October 10, 2011 Leave a comment

Women are better represented in astronomy and solid-Earth geophysics research than in other areas of physics, according to a major study by the Royal Astronomical Society, with a summary published in the October edition of the journal Astronomy and Geophysics. The RAS Demographic Survey of Astronomy and Geophysics collected data on more than 2000 research employees and students in astronomy and solid-Earth geophysics in the UK to establish the composition of this community and better understand its work. Less encouragingly, the survey results show how these research areas are poor at recruiting people from black and minority ethnic (BME) groups and that addressing this deficit remains a significant challenge.

The last comparable exercise took place in 1998 and at that time covered a slightly smaller community. This time the RAS commissioned Sean McWhinnie of Oxford Research and Policy to carry out the work, gathering data using both online questionnaires and internet research of departmental websites. The survey was carried out in the autumn of 2010 and spring of 2011.

Full Story: http://www.ras.org.uk/news-and-press/217-news2011/2017-astronomy-and-geophysics-bring-women-into-science