Detecting Exoplanets Using Eclipsing Binaries as Natural Starshades
We investigate directly imaging exoplanets around eclipsing binaries, using the eclipse as a natural tool for dimming the binary and thus increasing the planet to star brightness contrast. At eclipse, the binary becomes point-like, making coronagraphy possible. We select binaries where the planet-star contrast would be boosted by >10× during eclipse, making it possible to detect a planet that is ≳10× fainter or in a star system that is ∼2-3× more massive than otherwise. Our approach will yield insights into planet occurrence rates around binaries versus individual stars. We consider both self-luminous (SL) and reflected light (RL) planets. In the SL case, we select binaries whose age is young enough so that an orbiting SL planet would remain luminous; in U Cep and AC Sct, respectively, our method is sensitive to SL planets of ∼4.5MJ and ∼9MJ with current ground- or near-future space-based instruments, and ∼1.5MJ and ∼6MJ with future ground-based observatories. In the RL case, there are three nearby (≲50 pc) systems — V1412 Aql, RR Cae, RT Pic — around which a Jupiter-like planet at a planet-star separation of ≳20 mas might be imaged with future ground- and space-based coronagraphs. A Venus-like planet at the same distance might be detectable around RR Cae and RT Pic. A habitable Earth-like planet represents a challenge; while the planet-star contrast at eclipse and planet flux are accessible with a 6-8m space telescope, the planet-star separation is 1/3 – 1/4 of the angular separation limit of modern coronagraphy.
Stefano Bellotti, Ann Zabludoff, Ruslan Belikov, Olivier Guyon, Chirag Rathi
Comments: 23 pages, 9 figures, 3 tables. To be published in AJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2007.09623 [astro-ph.EP] (or arXiv:2007.09623v1 [astro-ph.EP] for this version)
Submission history
From: Stefano Bellotti
[v1] Sun, 19 Jul 2020 08:48:34 UTC (646 KB)
