Mass-Loss Rates for Massive Stars from Stellar Bowshocks I
Abstract
Massive stars lose a significant portion of their mass through stellar winds over the course of their lifetimes, and understanding the rate of mass-loss is critical for understanding stellar evolution and compact object genesis. Traditional methods of determining mass-loss rates rely on UV observations and parameterizing a "clumping" factor, which varies significantly and results in a two-order-of-magnitude difference between prediction and observation for stars with weak winds. We intend to address this "weak-wind problem" using a novel method to measure mass-loss rates of massive stars powering stellar bowshocks using optical spectroscopy of the central stars, far infrared measurements of the bowshock nebulae, and space velocities calculated from GAIA DR3 proper motions. This method utilizes the geometry of the bowshock and the principle of balancing the momentum flux between stellar winds and ambient interstellar material to make a mass-loss rate determination. We observed late-O and early-B type stars with bowshocks with the Apache Point Observatory 3.5m telescope with the KOSMOS long-slit spectrograph and the Wyoming Infrared Observatory's 2.3m telescope with an optical spectrograph. We used the emcee package in Python and interpolated between models from the PoWR OB-I grid to fit their spectra to find temperatures and surface gravities. We found that our sample spanned a range of stellar parameters, with temperatures varying from 18,000-38,000 K and the log of surface gravity ranging from 2.8-4.1 dex. Using these parameters and photometric data, we calculated predicted mass-loss rates. This work is supported by the National Science Foundation under REU grant AST 1852289.
- Publication:
-
American Astronomical Society Meeting Abstracts #243
- Pub Date:
- February 2024
- Bibcode:
- 2024AAS...24340801R