Mass of Cepheid V350 Sgr Incorporating Interferometry and the Companion Mass

TL;DR

This paper combines interferometry, ultraviolet spectroscopy, and Gaia data to accurately determine the mass of the Cepheid V350 Sgr and discusses methods to estimate Cepheid masses in binary systems.

Contribution

The study presents a novel combined approach using interferometry, UV spectra, and Gaia data to determine Cepheid masses more accurately.

Findings

Cepheid V350 Sgr mass is 4.7 ± 0.8 M_sun.

Companion mass is 2.6 ± 0.2 M_sun.

Methodology reduces uncertainties in Cepheid mass estimates.

Abstract

The system V350 Sgr has a classical Cepheid for the primary. Interferometry is presented for the system and the full orbit is determined. The mass of the companion has been determined from an {\it IUE} spectrum and comparison with the mass-temperature relation from Detached Eclipsing Binaries. Combined with the mass of the companion (2.6 $\pm$ 0.2 M$_\odot$), the mass of the Cepheid is determined to be 4.7 $\pm$ 0.8 M$_\odot$. For systems with less complete information, Cepheid masses can be determined from a single-lined spectroscopic orbit, {\it Gaia} proper motion anomalies, and the mass of the companion from the ultraviolet. Uncertainties resulting from different approaches to mass determination are discussed, and are expected to be reduced after the {\it Gaia} DR4 release. Temperatures for Morgan Keenan (MK) standard stars from the ultraviolet are also provided.