Binary Star Demographics in the Galactic Bulge
| Program ID | 19046 |
|---|---|
| Science Category | Stellar Physics |
| Program Type | Analysis |
| Category | Medium |
| Principal Investigator | Cheyanne Shariat |
| PI Institution | California Institute of Technology |
| Co-Investigators |
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| Abstract | Roman’s Galactic Bulge Time-Domain Survey (GBTDS) will enable the first completeness-corrected measurement of the close-binary population of the Galactic bulge. We propose to use the public GBTDS time-series products to identify detached eclipsing and ellipsoidal binaries, characterize their properties, and measure the selection function with injection--recovery simulations. Forward-modeling the observed samples through this measured selection function will yield the bulge's intrinsic close-binary fraction and the distributions of orbital period, eccentricity, and companion mass across the GBTDS footprint. Roman's GBTDS will provide high-cadence near-IR light curves for hundreds of millions of stars in some of the most crowded fields in the Galaxy, opening a dense, metal-rich stellar environment that has remained inaccessible to previous binary demographic studies. GBTDS will identify one million eclipsing binaries and ellipsoidal binaries with periods P=0.1-100 d, enabling a direct test of how close-binary demographics, interaction rates, and dynamical processing unfolds in the bulge environment. The same analysis will identify 10,000 post-common-envelope binaries containing white dwarfs and hundreds of candidate binaries containing neutron stars and black holes. The public catalogs, completeness products, and analysis code produced by this program will provide a lasting resource for studies of binary evolution, compact objects, and stellar multiplicity in the dense regions of the inner Milky Way. |