Abstract
The evaporation of exoplanetary atmospheres is thought to be driven by
high-energy irradiation. However, the actual mass loss rates are not
well constrained. Co-I Kipping has recently discovered that the star
KOI-314, an M1V dwarf at 65 pc distance, is orbited by two earth-sized
planets, the inner one of them rocky and the outer one gaseous (P_orb =
14d and 23d). Other recent works have shown an abundance of small rocky
planets in very close orbits around their host stars, suggesting that
the stellar high-energy irradiation evaporates away gaseous envelopes.
KOI-314 is the first nearby system in which earth-sized planets of both
types are detected, allowing us to constrain the efficiency of planetary
evaporation if the stellar X-ray irradiation is measured. We therefore
propose a 10 ks Chandra ACIS-S pointing to determine the stellar X-ray
luminosity and hardness ratio. The accuracy of the orbital solution
decreases quickly due to Transit-Timing Variations, which is why we ask
for DDT.
Original language | English |
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Type | Accepted observing proposal |
Publication status | Published - 01 Sep 2013 |