A search for self-lensing binaries with TESS and constraints on their occurrence rate

• DOI: 10.48550/arxiv.2410.13939
• Publication Date: 2024-10-17
• Authors: Natsuko Yamaguchi; Kareem El-Badry
• Keywords: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics - Solar and Stellar Astrophysics; 0103 physical sciences; FOS: Physical sciences; 01 natural sciences; Solar and Stellar Astrophysics (astro-ph.SR); Astrophysics - Earth and Planetary Astrophysics

Five self-lensing binaries (SLBs) have been discovered with Kepler light curves. They contain white dwarfs (WDs) in AU-scale orbits that gravitationally lens solar-type companions. Forming SLBs likely requires common envelope evolution when the WD progenitor is an AGB star and has a weakly bound envelope. No yet data from Transiting Exoplanet Survey Satellite (TESS), which observes far more stars than did. Identifying TESS made challenging by fact only most for $\sim$25 days at time, so single lensing event will be observed typical SLBs. TESS's smaller aperture also makes it sensitive to factor of $\sim$100 brighter those sensitive. We demonstrate nevertheless already $\sim$4 times detectable Kepler. describe search non-repeating signals curves present preliminary candidates spectroscopic follow-up ongoing. calculate sensitivity our injection recovery tests on Based 5 curves, we estimate $(1.1 \pm 0.6)\%$ are orbited WDs periods 100-1000 d. This implies space density + main sequence (MS) 20-100 larger astrometrically-identified MS Gaia DR3. conclude sample still quite incomplete, mainly because can unambiguously identified as such high mass ratios.