A Precision Measurement of the Mass of the Cepheid V350 Sgr
Abstract
An important HST UV legacy is the measurement of the masses of Cepheids. HST has provided double-lined spectroscopic binaries since the orbital velocity amplitude of hot companions can be measured on high resolution ultraviolet spectra. STIS UV E140H echelle observations of the Cepheid V350 Sgr will yield a dramatic improvement in the precision of its mass (5% or 0.25 solar masses vs the current 17%). This will allow a unique and critical test of the role of convective overshoot in the evolution of intermediate mass stars, by coupling the measured mass with a luminosity. Furthermore, the very accurate masses (1-2%) recently determined for two Cepheids in eclipsing binaries in the LMC mean the mass--luminosity relation for Cepheids can be compared for two metallicities. This will improve both confidence in the use of Cepheids as primary extragalactic distance indicators and also our understanding of the evolution of intermediate mass stars.
- Publication:
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HST Proposal
- Pub Date:
- December 2016
- Bibcode:
- 2016hst..prop14332E