Vetting the Lobster Diagram: Searching for Unseen Companions in Wide Binaries using NASA Space Exoplanet Missions

Abstract

Over the past decade, the number of known wide binary systems has exponentially expanded thanks to the release of data from the Gaia Mission. Some of these wide binary systems are actually higher-order multiples, where one of the components is an unresolved binary itself. One way to search for these systems is by identifying overluminous components in the systems. In this study, we examine 4947 K+K wide binary pairs from the SUPERWIDE catalog and quantify the relative color and luminosity of the components to find evidence for additional, unresolved companions. The method is best illustrated in a graph we call the "Lobster diagram." To confirm that the identified overluminous components are close binary systems, we cross-match our wide binaries with the TESS, K2 and Kepler archives and search for the signs of eclipses and fast stellar rotation modulation in the light curves. We find that $78.9\%\pm 20.7\%$ of the wide binaries which contain an eclipsing system are identified to be overluminous in the "Lobster Diagram" and $73.5\%\pm 12.4\%$ of the wide binaries which contain a component showing fast rotation ($P<5$) days also show an overluminous component. From these results, we calculate a revised lower limit on the higher-order multiplicity fraction for K+K wide binaries of $40.0\%\pm 1.6\%$. We also examine the higher-order multiplicity fraction as a function of projected physical separation and metallicity. The fraction is unusually constant as a function of projected physical separation while we see no statistically significant evidence that the fraction varies with metallicity.

Submitted and accepted to ApJ

References in corpus (12)

• Modules for Experiments in Stellar Astrophysics (MESA)
• astroquery: An Astronomical Web-Querying Package in Python
• A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties
• Unresolved stellar companions with Gaia DR2 astrometry
• Parallax Systematics and Photocenter Motions of Benchmark Eclipsing Binaries in Gaia EDR3
• New Distant Companions to Known Nearby Stars. II. Faint companions of Hipparcos stars and the frequency of wide binary systems
• The SUPERWIDE Catalog: A Catalog of 99,203 Wide Binaries Found in Gaia and Supplemented by the SUPERBLINK High Proper Motion Catalog
• A catalog of wide binary and multiple systems of bright stars from Gaia-DR2 and the Virtual Observatory
• Exploring the evolution of stellar rotation using Galactic kinematics
• The non-monotonic, strong metallicity dependence of the wide-binary fraction
• Spectroscopic orbits of subsystems in multiple stars. VI
• Bayesian Cross-Matching of High Proper Motion Stars in Gaia DR2 and Photometric Metallicities for $\sim$1.7 million K and M Dwarfs

Cited by in corpus (1)

• 15000 Ellipsoidal Binary Candidates in TESS: Orbital Periods, Binary Fraction, and Tertiary Companions