Detecting Exoplanets Using Eclipsing Binaries as Natural Starshades

Abstract

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 $>10\times$ during eclipse, making it possible to detect a planet that is $\gtrsim 10\times$ fainter or in a star system that is $\sim 2$-$3\times$ 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 $\sim$4.5$M_J$ and $\sim$9$M_J$ with current ground- or near-future space-based instruments, and $\sim$1.5$M_J$ and $\sim$6$M_J$ with future ground-based observatories. In the RL case, there are three nearby ($\lesssim 50$ pc) systems -- V1412 Aql, RR Cae, RT Pic -- around which a Jupiter-like planet at a planet-star separation of $\gtrsim 20$ 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.

23 pages, 9 figures, 3 tables. To be published in AJ. Typos corrected, full decimal digits in equation 1 coefficients added

References in corpus (58)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• The SIMBAD astronomical database
• A Survey of Stellar Families: Multiplicity of Solar-Type Stars
• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)
• Images of a fourth planet orbiting HR 8799
• A giant planet imaged in the disk of the young star Beta Pictoris
• The NASA Exoplanet Archive: Data and Tools for Exoplanet Research
• Long-Term Stability of Planets in Binary Systems
• Optical Images of an Exosolar Planet 25 Light Years from Earth
• Gaia Data Release 1: Astrometry - one billion positions, two million proper motions and parallaxes
• A probable giant planet imaged in the Beta Pictoris disk
• Discovery and spectroscopy of the young Jovian planet 51 Eri b with the Gemini Planet Imager
• On the Luminosity of Young Jupiters
• Planet formation around stars of various masses: The snow line and the frequency of giant planets
• Gaia Data Release 2: first stellar parameters from Apsis
• Tertiary companions to close spectroscopic binaries
• Theoretical Limits on Extrasolar Terrestrial Planet Detection with Coronagraphs
• Direct Imaging of a Cold Jovian Exoplanet in Orbit around the Sun-like Star GJ 504
• The Impact of Stellar Multiplicity on Planetary Systems, I.: The Ruinous Influence of Close Binary Companions
• The sdB+M Eclipsing System HW Virginis and its Circumbinary Planets
• Discovery of a young planetary mass companion to the nearby M dwarf VHS J125601.92-125723.9
• Two planets orbiting the recently formed post-common envelope binary NN Serpentis
• The Updated Multiple Star Catalog
• The Gaia astrophysical parameters inference system (Apsis). Pre-launch description
• Three Wide Planetary-Mass Companions to FW Tau, ROXs 12, and ROXs 42B
• APASS Landolt-Sloan BVgri photometry of RAVE stars. I. Data, effective temperatures and reddenings
• Confirmation of the planet around HD 95086 by direct imaging
• Clouds in the Coldest Brown Dwarfs: FIRE Spectroscopy of Ross 458C
• Characterization of exoplanets from their formation III: The statistics of planetary luminosities
• High-contrast Imaging Search for Planets and Brown Dwarfs around the Most Massive Stars in the Solar Neighborhood
• Origin of apparent period variations in eclipsing post-common-envelope binaries
• Stellar Companions of Exoplanet Host Stars in K2
• Luminosity of young Jupiters revisited. Massive cores make hot planets
• Circumbinary Planets Orbiting the Rapidly Pulsating Subdwarf B-type binary NY Vir
• Calculating the Habitable Zone of Binary Star Systems I: S-Type Binaries
• Calculating the Habitable Zone of Binary Star Systems II: P-Type Binaries
• A triple origin for the lack of tight coplanar circumbinary planets around short-period binaries
• Fomalhaut b: Independent Analysis of the Hubble Space Telescope Public Archive Data
• New prospects for observing and cataloguing exoplanets in well detached binaries
• On the Likelihood of Planet Formation in Close Binaries
• A Circumbinary Planet in Orbit Around the Short-Period White-Dwarf Eclipsing Binary RR Cae
• SPOTS: The Search for Planets Orbiting Two Stars: II. First constraints on the frequency of sub-stellar companions on wide circumbinary orbits
• Long-Term Stability of Planets in the $\alpha$ Centauri System
• New HST data and modeling reveal a massive planetesimal collision around Fomalhaut
• A First-Look Atmospheric Modeling Study of the Young Directly-Imaged Planet-Mass Companion, ROXs 42Bb
• Detecting circumbinary planets using eclipse timing of binary stars - numerical simulations
• Habitable Zones with Stable Orbits for Planets around Binary Systems
• The B-Star Exoplanet Abundance Study: a co-moving 16-25 Mjup companion to the young binary system HIP 79098
• A New Class of Nascent Eclipsing Binaries with Extreme Mass Ratios
• SPOTS: The Search for Planets Orbiting Two Stars. III. Complete Sample and Statistical Analysis
• SPOTS: The Search for Planets Orbiting Two Stars. I. Survey description and first observations
• Mass loss out of close binaries
• On High-Contrast Characterization of Nearby, Short-Period Exoplanets with Giant Segmented-Mirror Telescopes
• Lessons for WFIRST CGI from ground-based high-contrast systems
• A comparison between observed Algol-type double stars in the Solar neighborhood and evolutionary computations of galactic case A binaries with a B-type primary at birth
• On the frequency of planetary systems around G-dwarfs

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