Austrian Early Career Conference 2024

Contribution:
Poster

Authors:
Aayush Desai

Affiliations:
Institute of Science and Technology

Title:
Runaway Stripped Stars in the Milky Way Galaxy: A Population Synthesis Study

Abstract:
Given the recent leaps in our ability to explore our Cosmic neighbourhood, one might expect that we know a great deal about it. But there is still a lot to learn. A study estimates that two-thirds of the most massive (brightest) stars should exist in binaries. A majority of these binaries should evolve through a mass transfer phase, creating hot, envelope-stripped helium stars. Astonishingly, such a system has not been observed in the Milky Way! To inform future observations of stripped stars, I used a binary population synthesis code that utilises single and binary stellar evolution models computed with the MESA code as an initial framework. Subsequently, the code interpolates between the models to ascertain the parameters of the particular systems. I found that roughly 6000 systems with atleast 1 stripped star with mass between 2−8 M⊙ should exist in the Milky Way alone. These stars are ejected when the companion star collapses in a supernova explosion that disrupts the binary system. A promising method to identify these outlier stars is to compare its velocity with its immediate neighbours. Given the exquisitely high astrometric accuracy of the Gaia DR3, such high-velocity stars could potentially be recognised from the data. Although the model is simplistic and does require further improvements, the early results suggest that a sub-set of the runaway stripped star population in the Milky Way could be detectable. These populations could guide future observations and provide an interesting avenue for identifying stripped stars.