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Post Info TOPIC: Upper Scorpius OB Association
Blobrana


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RE: Upper Scorpius OB Association
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Blobrana


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A planet has been pictured outside our Solar System which appears to be circling a star like our own Sun - a first in astronomy.

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Blobrana


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1RXS J160929.1-210524
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Astronomers have unveiled what is likely the first picture of a planet around a normal star similar to the Sun.
Three University of Toronto scientists used the Gemini North telescope on Mauna Kea in Hawaii to take images of the young star 1RXS J160929.1-210524 (which lies about 500 light-years from Earth) and a candidate companion of that star. They also obtained spectra to confirm the nature of the companion, which has a mass about eight times that of Jupiter, and lies roughly 330 times the Earth-Sun distance away from its star. (For comparison, the most distant planet in our solar system, Neptune, orbits the Sun at only about 30 times the Earth-Sun distance.) The parent star is similar in mass to the Sun, but is much younger.

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Blobrana


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Title: Direct Imaging and Spectroscopy of a Planetary Mass Candidate Companion to a Young Solar Analogue
Authors: David Lafrenière, Ray Jayawardhana, Marten H. van Kerkwijk (University of Toronto)

We present near-infrared imaging and spectroscopy of a planetary mass candidate companion to 1RXS J160929.1-210524, a roughly solar-mass member of the ~5 Myr-old Upper Scorpius association. The object, separated by 2.22" or 330 AU at ~150 pc, has infrared colours and spectra suggesting a spectral type of L4(-2/+1) and a temperature of 1800(-100/+200) K. The H- and K-band spectra provide clear evidence of low surface gravity, and thus youth. Based on the widely used DUSTY models, we infer a mass of 8(-1/+4) Mjup. If gravitationally bound, this would be the lowest mass companion imaged around a normal star thus far, and its existence at such a large separation would pose a serious challenge to theories of star and planet formation.

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Blobrana


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First image of  alien  planet

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Blobrana


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Date:
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First photo of planet around alien star

Astronomers believe they have taken the first amazing photo of a planet around another star like the Sun. The alien world shows up as a tiny orange disk in the image captured by Canadian scientists with a giant telescope in Hawaii.

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Blobrana


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Upper Scorpius OB Association
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Title: A Large-Area Search for Low-Mass Objects in Upper Scorpius II: Age and Mass Distributions
Authors: Catherine L. Slesnick, Lynne A. Hillenbrand, John M. Carpenter

We present continued results from a wide-field, ~150 deg^2, optical photometric and spectroscopic survey of the northern part of the ~5 Myr-old Upper Scorpius OB Association. Photometry and spectral types were used to derive effective temperatures and luminosities and place newly identified association members onto a theoretical Hertzsprung-Russell diagram. From our survey, we have discovered 145 new low mass members of the association, and determined ~10% of these objects to be actively accreting material from a surrounding circumstellar disk. Based on comparison of the spatial distributions of low and high mass association members, we find no evidence for spatial segregation by mass within the northern portion of the association. Measured data are combined with pre-main sequence evolutionary models to derive a mass and age for each star. Using Monte Carlo simulations we show that, taking into account known observational uncertainties, the observed age dispersion for the low mass population in USco is consistent with all stars forming in a single burst ~5 Myr ago, and place an upper limit of ±3 Myr on the age spread if the star formation rate has been constant in time. We derive the first spectroscopic mass function for USco that extends into the substellar regime, and compare these results to those for three other young clusters and associations.

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