Fundamental Parameters of 4 Massive Eclipsing Binaries in Westerlund 1

TL;DR

This study analyzes four massive eclipsing binary systems in Westerlund 1 to determine fundamental stellar parameters, providing insights into massive star evolution, cluster distance, and progenitor masses of exotic objects.

Contribution

It presents the first detailed fundamental parameters of four massive eclipsing binaries in Westerlund 1, aiding evolutionary models and cluster characterization.

Findings

Masses and radii of component stars determined

Constraints on massive star evolution models

Lower limit for magnetar progenitor mass

Abstract

Westerlund 1 is one of the most massive young clusters known in the Local Group, with an age of 3-5 Myr. It contains an assortment of rare evolved massive stars, such as blue, yellow and red supergiants, Wolf-Rayet stars, a luminous blue variable, and a magnetar, as well as 4 massive eclipsing binary systems (Wddeb, Wd13, Wd36, WR77o, see Bonanos 2007). The eclipsing binaries present a rare opportunity to constrain evolutionary models of massive stars, the distance to the cluster and furthermore, to determine a dynamical lower limit for the mass of a magnetar progenitor. Wddeb, being a detached system, is of great interest as it allows determination of the masses of 2 of the most massive unevolved stars in the cluster. We have analyzed spectra of all 4 eclipsing binaries, taken in 2007-2008 with the 6.5 meter Magellan telescope at Las Campanas Observatory, Chile, and present fundamental parameters (masses, radii) for their component stars.