A Search For Young Stars in the Magellanic Stream
Abstract
In 1990, Irwin and collaborators discovered blue stars in the InterCloud region (ICR) between the Magellanic Clouds. However, it has been a challenge to conclude how these young stars formed ~10 kpc away from the main bodies of the Clouds, until now. We present results of the first nearly-complete spectroscopic survey of these stars using the SMARTS-1.5m telescope + R-C Spectrograph (RC), and high-resolution follow-up with the Magellan 6.5m telescope + MIKE spectrograph (MIKE), which we combine with Gaia DR2 data. Both the RC and MIKE spectra were compared to synthetic spectra to derive Teff, logg, [Fe/H], vsini, and radial velocity for each star. We used the spectroscopic parameters and Gaia proper motions and parallaxes to help determine if the blue stars came from the Large Magellanic Cloud (LMC), the Small Magellanic Cloud, the LMC filament of the Magellanic Stream (MS), or are foreground contaminants. Among the blue stars, a group of seven stars were identified as rapid rotators and Magellanic-like RVs. Of these stars, two are associated with the outer LMC and three are part of a foreground moving group at a heliocentric distance of 7 kpc. One star, with an age ~65 Myr based on the spectroscopic parameters, is consistent with having formed in the gas of the LMC filament of the Magellanic Stream. This interesting star could help place constraints on star formation in low density, metal-poor gas, and provide a detailed chemical composition of the MS gas, an important clue to its origin.
- Publication:
-
American Astronomical Society Meeting Abstracts #233
- Pub Date:
- January 2019
- Bibcode:
- 2019AAS...23335107P