K2-22b

K2-22b (also known as EPIC 201637175 b) is an exoplanet 801 ly from Earth, rapidly orbiting the red dwarf K2-22 with an orbital period of 9.145872 hours.^[2] It has a mass of 0.02 M_E and a radius below 0.71 M_E.^[3] The planet was not detected in the K2 photometry. K2 photometry reveals the presence of an anomalous light curve consistent with evaporation of dust from the planet. This dust forms a tail both ahead and behind the planet, similar to some comets in the Solar System.^[1] The evaporation of this dust requires a low surface gravity from the host planet, implying it is a low mass, "Mars, Mercury, or even lunar sized bodies with surface gravities of 1/6 to 1/3 that of Earth are to be preferred."^[1]

The survey in 2020 has failed to validate the existence of the planet, although did not claim it to be a false positive.^[4]

The observation of planetary system in 2021 has failed to detect the planet itself, placing an upper limit of 0.71R_🜨 on its size. With the observed mass loss rate, the probable planet mass is 0.02M_E, and the planet will be gone in 21 million years in future.^[3]

References

^ ^a ^b ^c Sanchis-Ojeda, R.; et al. (2015). "The K2-ESPRINT Project I: Discovery of the Disintegrating Rocky Planet K2-22b with a Cometary Head and Leading Tail". The Astrophysical Journal. 812 (2). 112. arXiv:1504.04379. Bibcode:2015ApJ...812..112S. doi:10.1088/0004-637X/812/2/112.
^ ^a ^b ^c ^d "K2-22 b CONFIRMED PLANET OVERVIEW PAGE". NASA Exoplanet Archive. Retrieved 2015-10-14.
^ ^a ^b ^c ^d Schlawin, Everett; Su, Kate Y. L.; Herter, Terry; Ridden-Harper, Andrew; Apai, Dániel (2021), "LBT Reveals Large Dust Particles and a High Mass-loss Rate for K2-22 B", The Astronomical Journal, 162 (2): 57, arXiv:2106.07648, Bibcode:2021AJ....162...57S, doi:10.3847/1538-3881/ac0b41, S2CID 235436223
^ Adams, Elisabeth R.; Jackson, Brian; Johnson, Samantha; Ciardi, David R.; Cochran, William D.; Endl, Michael; Everett, Mark E.; Furlan, Elise; Howell, Steve B.; Jayanthi, Prasanna; MacQueen, Phillip J.; Matson, Rachel A.; Partyka-Worley, Ciera; Schlieder, Joshua; Scott, Nicholas J.; Stanton, Sevio M.; Ziegler, Carl (2020), ULTRA SHORT PERIOD PLANETS IN K2 III: NEIGHBORS ARE COMMON WITH 12 NEW MULTI-PLANET SYSTEMS AND 26 NEWLY VALIDATED PLANETS IN CAMPAIGNS 0-8, 10, arXiv:2011.11698

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Space probes	SMAP (weather satellite; Jan 2015) LISA Pathfinder (technology demonstration; Dec 2015)
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