Archive for April 29, 2013

Looking For Life By The Light Of Dying Stars

Because it has no source of energy, a dead star — known as a white dwarf — will eventually cool down and fade away. But circumstantial evidence suggests that white dwarfs can still support habitable planets, says Prof. Dan Maoz of Tel Aviv University’s School of Physics and Astronomy.

Now Prof. Maoz and Prof. Avi Loeb, Director of Harvard University’s Institute for Theory and Computation and a Sackler Professor by Special Appointment at TAU, have shown that, using advanced technology to become available within the next decade, it should be possible to detect biomarkers surrounding these planets — including oxygen and methane — that indicate the presence of life.

Published in the Monthly Notices of the Royal Astronomical Society, the researchers’ “simulated spectrum” demonstrates that the James Webb Space Telescope (JWST), set to be launched by NASA in 2018, will be capable of detecting oxygen and water in the atmosphere of an Earth-like planet orbiting a white dwarf after only a few hours of observation time — much more easily than for an Earth-like planet orbiting a sun-like star.

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Universality Of Circular Polarization In Star- And Planet-Forming Regions: Implications For The Origin Of Homochirality Of Life

A research team with Jungmi KWON (GUAS/NAOJ) has performed deep imaging linear and circular polarimetry of the ‘Cat’s Paw Nebula’ (NGC 6334) located in the constellation Scorpius, successfully detecting high degrees of circular polarization (CP) of as much as 22% in NGC 6334. The detected CP degree is the highest ever observed.

In addition, the team has presented the first systematic survey of a combination of linear and circular polarimetry in nine star- and planet-forming regions. As the results of statistical analysis of observations of various star-forming regions, CPs were detected in nine star- and planet-forming regions. Putting it differently, it can be said that CP is a universal feature of star- and planet-forming regions. The team’s findings enable us to obtain information about magnetic fields of circumstellar structures around protostars, which is difficult to obtain using existing methods.

There is a hypothesis that large CP causes homochirality of amino acids and that left-handed amino acids come from outer space. The team’s findings imply an extraterrestrial origin of homochirality of life, from the universality of CP detected in star- and planet-forming regions.

This research is part of an ongoing survey project of wide-field near-infrared (JHKs) imaging polarimetry for star-forming regions (PI: Motohide TAMURA, University of Tokyo/NAOJ). Doctoral student Jungmi KWON, who is contributing to the project, led this research with nine international researchers from Japan and the United Kingdom. The team’s findings were published in the Astrophysical Journal Letter on March 1, 2013.

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‘Standard Candle’ Supernova Extraordinarily Magnified By Gravitational Lensing

A team of researchers at the Kavli IPMU led by Robert Quimby has identified what may prove to be the first ever Type Ia supernova (SNIa) magnified by a strong gravitational lens. In this work, the ‘standard candle’ property of Type Ia supernovae is used to directly measure the magnification due to gravitational lensing. This provides the first glimpse of the science that will soon come out of dark matter and dark energy studies derived from deep, wide-field imaging surveys.

The supernova, named PS1-10afx, was discovered by the Panoramic Survey Telescope & Rapid Response System 1 (Pan-STARRS1). PS1-10afx exploded over 9 billion years ago, which places it far further than typical Pan-STARRS1 discoveries. Based on this distance and its relatively bright appearance, the Pan-STARRS1 team concluded that PS1-10afx was intrinsically very luminous. The inferred luminosity, about 100 billion times greater than our Sun, is comparable to members of a new, rare variety of superluminous supernovae (SLSNe), but that is where the similarities end.

SLSNe typically have blue colors, and their brightness changes relatively slowly with time. PS1-10afx on the other hand was rather red even after correcting for its redshift, and its brightness changed as fast as normal supernovae. There is no known physical model that can explain how a supernova could simultaneously be so luminous, so red, and so fast.

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NASA Probe Gets Close-Up Views Of Large Hurricane On Saturn

Image Credit: NASA/JPL-Caltech/SSI

Image Credit: NASA/JPL-Caltech/SSI

NASA’s Cassini spacecraft has provided scientists the first close-up, visible-light views of a behemoth hurricane swirling around Saturn’s north pole.

In high-resolution pictures and video, scientists see the hurricane’s eye is about 1,250 miles (2,000 kilometers) wide, 20 times larger than the average hurricane eye on Earth. Thin, bright clouds at the outer edge of the hurricane are traveling 330 mph(150 meters per second). The hurricane swirls inside a large, mysterious, six-sided weather pattern known as the hexagon.

“We did a double take when we saw this vortex because it looks so much like a hurricane on Earth,” said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena. “But there it is at Saturn, on a much larger scale, and it is somehow getting by on the small amounts of water vapor in Saturn’s hydrogen atmosphere.”

Scientists will be studying the hurricane to gain insight into hurricanes on Earth, which feed off warm ocean water. Although there is no body of water close to these clouds high in Saturn’s atmosphere, learning how these Saturnian storms use water vapor could tell scientists more about how terrestrial hurricanes are generated and sustained.

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Detection Of Two New Exoplanets With Kepler, SOPHIE And HARPS-N

An international team of astronomers, including Alexandre Santerne of the EXOEarths team, identified and characterized two new exoplanets, thanks to combined observations from the Kepler space telescope, plus SOPHIE and HARPS-N spectrographs.

These planets, named KOI-200 b and KOI-889 b are among the first detected with the new high-accuracy spectrograph HARPS-N, the northern hemisphere counterpart of the most prolific exoplanet hunter, HARPS (ESO). CAUP researcher Alexandre Santerne commented: “The SOPHIE spectrograph was already playing an important role in the characterization of Kepler planets by unveiling the true nature of the candidates and measuring the mass of giant planets. With the new HARPS-N spectrograph, with an even better accuracy, we expect to characterize much smaller exoplanets, hopefully down to the size of the Earth.”

The new planets have about the size of Jupiter, but eccentric orbits with periods of less than 10 days. These new results help to further understand the evolution of orbits of these planets located very close to their star, known as “hot Jupiters”

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