Detecting Exoplanets Using Eclipsing Binaries as Natural Starshades. (arXiv:2007.09623v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Bellotti_S/0/1/0/all/0/1">Stefano Bellotti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zabludoff_A/0/1/0/all/0/1">Ann Zabludoff</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Belikov_R/0/1/0/all/0/1">Ruslan Belikov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guyon_O/0/1/0/all/0/1">Olivier Guyon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rathi_C/0/1/0/all/0/1">Chirag Rathi</a>
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 $>10times$ during eclipse, making it possible to detect a
planet that is $gtrsim10times$ fainter or in a star system that is
$sim2$-$3times$ 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
($lesssim50$ pc) systems — V1412 Aql, RR Cae, RT Pic — around which a
Jupiter-like planet at a planet-star separation of $gtrsim20$ 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.
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 $>10times$ during eclipse, making it possible to detect a
planet that is $gtrsim10times$ fainter or in a star system that is
$sim2$-$3times$ 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
($lesssim50$ pc) systems — V1412 Aql, RR Cae, RT Pic — around which a
Jupiter-like planet at a planet-star separation of $gtrsim20$ 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.
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