Archive for November 16, 2012

A Newly Identified Separate Star Cluster In Front Of The Orion Nebula Cluster

November 16, 2012 Leave a comment

Using images from the 340 Mpx MegaCam camera on the Canada-France-Hawaii Telescope (CFHT) from the summit of Mauna Kea, astronomers identified the massive cluster of young stars NGC 1980 to be a clearly separate entity from the main cluster of the most studied star formation region in the Galaxy. A technique relying on the combination of optical, infrared, and mid-infrared data ensures astronomers are sampling only stars located in the foreground of the Orion nebula. This technique also led them to the discovery of a nearby small star cluster, baptized L1641W.

Not surprisingly, astronomers see the Orion nebula as the benchmark for star formation studies, a true golden standard, and most of the established measurements of how stars form have been derived from this important region. For example, the distribution of stellar and brown dwarfs masses at birth, their relative age, their spatial distribution, and the properties of the planet forming circumstellar disks surrounding the young stars.

But as it turns out, reality is more complicated. Recent observations of the Orion nebula from the Canada-France-Hawaii Telescope (CFHT) with the 340 Mpx MegaCam camera coupled to previous observations with ESA’s Herschel and XMM-Newton, NASA’s Spitzer and WISE, as well as 2MASS and Calar Alto, revealed the cluster known as NGC 1980 as being a clearly distinct massive cluster of slightly older stars in front of the nebula. Although astronomers knew of the presence of a foreground stellar population since the 1960s, the new CFHT observations revealed that this population is more massive than first thought, and it is not uniformly distributed, clustering around the star iota Ori at the southern tip of Orion’s sword.


Lowell Astronomer, Collaborators Point The Way For Exoplanet Search

November 16, 2012 Leave a comment

Though the search for planets around other stars, or exoplanets, is showing researchers that planets are abundant in our galaxy, it helps a great deal to have directions when searching for as-of-yet undiscovered exoplanets. Lowell astronomer Evgenya Shkolnik and her collaborators have written such a set of directions, if you will.

By looking for markers in spectroscopic data and measuring the motions of the stars, Shkolnik and her collaborators were able to carefully examine the age of each stars. Since low-mass stars are small and dim, they are good candidates for directly imaging planets around them. And young stars make it even easier since the young planet is still hot and bright. Plus, knowing the planetary system’s age allows for the characterization of the planet itself beyond the initial detection.

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New Australian Telescope Set To Find 700,000 Galaxies

November 16, 2012 Leave a comment

Australia’s newest radio telescope is predicted to find an unprecedented 700,000 new galaxies, say scientists planning for CSIRO’s next-generation Australian Square Kilometre Array Pathfinder (ASKAP). In a paper to be published Sunday in the Monthly Notices of the Royal Astronomical Society, Australian researchers have combined computer simulations with ASKAP’s specifications to predict the new telescope’s extraordinary capabilities. “ASKAP is a highly capable telescope. Its surveys will find more galaxies, further away and be able to study them in more detail than any other radio telescope in the world until the SKA Is built,” said Dr Alan Duffy from The University of Western Australia node of the International Centre for Radio Astronomy Research.

Combining a large simulation of the Universe with new theories of galaxy formation − including the effects of supermassive black holes − had led scientists to accurately predict where as-yet undiscovered galaxies should be located, Dr Duffy said.

Dr Duffy said the new ASKAP galaxy surveys would also allow astronomers to probe the nature of one of astronomy’s greatest mysteries – Dark Energy.

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Discovery Of A Giant Gap In The Disk Of A Sun-like Star

November 16, 2012 Leave a comment

A large international team of astronomers led by Jun Hashimoto (National Astronomical Observatory of Japan) and Ruobing Dong (Princeton University) has used the High Contrast Instrument for the Subaru Next Generation Adaptive Optics (HiCIAO) to observe and examine PDS 70, a young star about 10 million years old with a mass similar to that of the Sun. Images captured from the observations clearly show a giant gap inside the protoplanetary disk, the largest ever found among lower mass stars similar to the Sun. A protoplanetary disk is where planets form, and the gravitational force of newborn planets may account for the huge gap between the inner edge of the disk and the central star. No single planet, regardless of how heavy or efficient it is in its formation, is sufficient to create such a giant gap. The researchers think that the gap in PDS 70’s protoplanetary disk may have resulted from the birth of multiple planets. The high contrast images from the observations allowed the researchers to study the details of the disk, which then enabled them to directly reveal the site of formation of one and possibly more planets. The research team is now attempting to detect those planets.

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