Active Research

Interloper stars in the Large Magellanic Cloud

Interloper Stars in the Large Magellanic Cloud

Dana Casetti, Terry Girard, William van Altena

A recent radial-velocity study (Olsen et al. 2011) of ~5900 red giants and supergiants in the LMC has uncovered a population of a few hundred stars that have distinct kinematics from the stars of the LMC disk. Metallicities of a subsample of these stars were found to be similar to stars in the Small Magellanic Cloud. This led the authors to suggest the stars were captured from the SMC by the LMC in a previous interaction of the Clouds.

We have used SPM4 proper motions to analyze the extra two velocity dimensions of these stars. Combining the proper motions and radial velocities, we were able to determine that the SMC-captured stars rotate in the same sense as the LMC disk, but at an inclination of about 50 degrees with respect to the disk. The existence of these stars, together with other facts, point to an off-center, moderate to highly inclined collision of the SMC with the LMC disk some 100 to 200 million years ago.


Image Credits: (header) Image of prominence, SOHO (ESA & NASA)


09.18.2014 Planet Hunters v2.0 now online
A team, led by Professor Debra Fischer, has just released Planet Hunters v2.0, a new version of their previous successful “Zooniverse” site, which allows the public to assist in searching data from NASA’s Kepler spacecraft for potential planet candidates. Version 1 has already discovered a large number of planet candidates as well as confirmed several planets, with the assistance of nearly 300,000 volunteers from all around the world. The project continues with the aim to derive planet occurrence rates as a function of spectral type, and will include data from NASA’s second generation Kepler spacecraft, K2...
09.11.2014 YCAA Postdoctoral Prize Fellowship Invites Applications
The Yale Center for Astronomy and Astrophysics invites applications for the YCAA Postdoctoral Prize Fellowship in Astronomy and Astrophysics, to be awarded to a young scientist of exceptional ability who will have received her/his Ph.D. by June 2014 in observational, theoretical, or experimental astronomy or astrophysics/cosmology. The Fellowship is for three years (renewed annually subject to performance), and offers competitive salary, benefits, and research funds. For more information, and to apply please see the Academic Jobs Online listing.
08.27.2014 Yale scientists see the birth of a massive galaxy, hidden by dust
Graduate student Erica Nelson and her collaborators have discovered a window into the early, violent formation of the cores of the universe’s monster galaxies, obscured behind walls of dust, using the NASA/ESA Hubble Space Telescope and a telescope from the W.M. Keck Observatory in Hawaii. The discovery offers important clues about an early phase of galaxy development, from a time just 3 billion years after the Big Bang. The research appears in the journal Nature.

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