Multiplicity properties of the pre-supernova population of NGC330
Abstract
The multiplicity properties of massive stars are one of the important outstanding issues in stellar evolution. We investigate the multiplicity of an almost complete census of red supergiant stars (RSGs) in NGC 330, a young massive cluster in the Small Magellanic Cloud. Using a combination of multi-epoch HARPS and MUSE spectroscopy, we estimate radial velocities and assess the kinematic and multiplicity properties of 15 RSGs in NGC 330. We detect significant radial velocity variability in our multi-epoch observations and distinguish between variations caused by atmospheric activity and those caused by binarity. We account for observational biases and estimate the intrinsic binary fraction for RSGs in NGC 330 as fRSG= 0.3±0.1 for orbital periods in the range 2.3 < log P [days] < 4.3, with q > 0.1. From the RSG population we estimate the age of NGC 330 to be 45±5 Mya and estimate a red straggler fraction of 50%. The RSG binary fraction appears to be lower than that of main-sequence massive stars, which is understood as a result of binary interactions in previous evolutionary phases.
- Publication:
-
XIV.0 Scientific Meeting (virtual) of the Spanish Astronomical Society
- Pub Date:
- July 2020
- Bibcode:
- 2020sea..confE.175P