How Low Can You Go: Exploring the Extreme Mass Ratio of Massive Binary Stars
email: abrahae1@my.erau.edu
Abstract
Massive stars burn bright and die young, and yet play a vital role in the evolution of our Universe. Massive stars are primarily found with companions in binary or multiple systems, but observational bias has obstructed the detection of extreme mass ratio binaries. With the advancement of high spatial resolution instrumentation, we are now poised to explore the lower end of the binary mass ratio, consisting of sub-solar, pre-main sequence stars. Here I present an analysis of seven massive stars in the young, active star-forming region M17 using data from the Spectro-Polarimetric High contrast Exoplanet REsearch (SPHERE) instrument on the Very Large Telescope. A radial velocity study of M17 by Ramirez–Tannus et al. (2017, DOI:10.1051/0004-6361/201629503) found fewer binary systems than expected. Our study is complementary to the previous work in the region to search for wide companions to massive stars in order to fill in our picture of massive star formation and the effect of multiple systems on the dynamical history of the region. SPHERE is uniquely capable of probing the lower end of the binary mass ratio due to its ground-breaking extreme adaptive optics and coronagraphic capabilities which allow us to achieve greater contrast ratios than traditional adaptive optics. We utilized the high spatial resolution imaging techniques of SPHERE in order to resolve binary systems with contrast ratios of up to 10 mag in the infrared and detect stellar companions to massive stars in the subsolar mass ranges. We present simultaneous dual-band imaging and integral-field spectroscopy of massive stars ranging from O4V–O9V. From a preliminary inspection, we found potential companions for all seven target stars. We measured flux contrast, position angles, and angular separation of our systems. Utilizing the Vortex Image Processing pipeline, we applied the negative fake companion technique in order to characterize the companions with differential magnitudes. Using this analysis, we will determine if the detected companions are foreground or field objects and estimate their mass ratio.
This work is distributed under the Creative Commons CC BY 4.0 Licence.
Paper presented at the 41st Liège International Astrophysical Colloquium on “The eventful life of massive star multiples,” University of Liège (Belgium), 15–19 July 2024.
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