Study Identifies 165 New Targets for Planet Hunters

An international team of astronomers has published a list of 165 young low-mass stars and brown dwarfs within 100 light-years of Sun – targets for exoplanet searches, including 20 very strong candidates.

This Keck 2 infrared image shows a star, identified by Dr Evgenya Shkolnik, and a young brown dwarf companion with a mass of about 32 Jupiter masses, the physical separation is about 120 AU (B. Bowler / IFA)

The astronomers sifted through data of about 8,700 stars within 100 light years of the Sun to find these young low-mass targets.

By looking for markers in spectroscopic data collected with the W. M. Keck Observatory and the Canada-France-Hawaii telescope, and measuring the motions of the stars with the Carnegie Institution for Science’s du Pont telescope in Chile, they were able to carefully examine the age of each star.

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.

“Since low-mass stars are the most common type of star in our galaxy, most planets probably reside in these environments,” explained Brendan Bowler, a graduate student at the University of Hawai‘i’s Institute for Astronomy.

“Finding young versions of these stars to search for planets is fundamental to understanding the galactic census of exoplanet’s,” he said.

“These young stars help point the way. And if the Jupiter-mass planets are there, we will find them,” said Dr Evgenya Shkolnik of Lowell Observatory, a lead author of the study published in the Astrophysical Journal (arXiv.org version).

“In this search, planet hunters are happy to have directions but they know the landscape of our understanding is subject to change.”

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Bibliographic information: Shkolnik EL et al. 2012. Identifying the Young Low-mass Stars within 25 pc. II. Distances, Kinematics, and Group Membership. ApJ 758, 56; doi: 10.1088/0004-637X/758/1/56