LP 791-18

High proper motion red dwarf in Crater
LP 791-18
Observation data
Epoch J2000      Equinox J2000
Constellation Crater[1]
Right ascension 11h 02m 45.95462s[2]
Declination −16° 24′ 22.2882″[2]
Apparent magnitude (V) 16.9±0.2[3]
Characteristics
Evolutionary stage Red dwarf (main sequence)
Spectral type M6.1±0.7V[3]
Astrometry
Proper motion (μ) RA: -221.291 mas/yr[2]
Dec.: -58.841 mas/yr[2]
Parallax (π)37.5225 ± 0.0392 mas[2]
Distance86.92 ± 0.09 ly
(26.65 ± 0.03 pc)
Details[3]
Mass0.139±0.005 M☉
Radius0.17±0.018 R☉
Temperature2960±55 K
Metallicity [Fe/H]-0.09±0.19 dex
Age0.5±0.064 Gyr
Other designations
LP 791-18, TOI-736, TIC 181804752, 2MASS J11024596-1624222[4]
Database references
SIMBADdata

LP 791-18 (TOI-736) is a cool M dwarf star in the constellation Crater, located 26.65 parsecs (86.9 light-years) away from Earth.[3]

The star is one of the smallest known to host exoplanets.[5] In 2019 two exoplanets in transit around it were announced by TESS,[3] and a third planet was discovered in Spitzer Space Telescope data in 2023.[5]

Planetary system

Artist's impression of LP 791-18 d, with c in the background[6]

The innermost planet, b, is a super-Earth and the outermost planet, c, is a mini-Neptune. They were discovered together in 2019.[3] The middle planet, d, is an Earth-mass world discovered in 2023. It may potentially be tidally heated by interactions with planet c, which would lead to abundant volcanoes similar to Jupiter's moon Io.[5] As the planet d is in the inner edge of the habitable zone, liquid water could condense on the side of the planet that faces away from the host star.[6]

In 2021 planet c was suggested for atmospheric analysis by the James Webb Space Telescope.[7]

The LP 791-18 planetary system[5]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b — 0.00978±0.00012 0.9479981±0.0000021 — 88.37+0.94
−0.95° 		1.212+0.059
−0.058 R🜨
d 0.9+0.5
−0.4 M🜨 		0.01992±0.00014 2.753436±0.000013 0.0015±0.00014 89.34±0.41° 1.032+0.044
−0.043 R🜨
c 7.1±0.7 M🜨 0.02961+0.00035
−0.00036 		4.9899093+0.0000074
−0.0000072 		0.00008±0.00004 89.78±0.13° 2.438±0.096 R🜨

References

  1. ^ "Finding the constellation which contains given sky coordinates". djm.cc. 2 August 2008.
  2. ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. ^ a b c d e f Crossfield, Ian J. M.; Waalkes, William; Newton, Elisabeth R.; Narita, Norio; Muirhead, Philip; Ment, Kristo; et al. (2019). "A Super-Earth and Sub-Neptune Transiting the Late-type M Dwarf LP 791-18". The Astrophysical Journal Letters. 883 (1): L16. arXiv:1906.09267. Bibcode:2019ApJ...883L..16C. doi:10.3847/2041-8213/ab3d30.
  4. ^ "LP 791-18". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 19 May 2023.
  5. ^ a b c d Peterson, Merrin S; Benneke, Björn; Collins, Karen; Piaulet, Caroline; Crossfield, Ian JM; Ali-Dib, Mohamad; et al. (2023). "A temperate Earth-sized planet with tidal heating transiting an M6 star". Nature. 617 (7962): 701–705. doi:10.1038/s41586-023-05934-8. hdl:11603/28165. PMID 37198481.
  6. ^ a b Kazmierczak, Jeanette (16 May 2023). "NASA's Spitzer, TESS Find Potentially Volcano-Covered Earth-Size World". NASA. Retrieved 19 May 2023.
  7. ^ Phillips, Caprice L.; Wang, Ji; Kendrew, Sarah; Greene, Thomas P.; Hu, Renyu; Valenti, Jeff; Panero, Wendy R.; Schulze, Joseph (2021). "Detecting Biosignatures in the Atmospheres of Gas Dwarf Planets with the James Webb Space Telescope". The Astrophysical Journal. 923 (2): 144. arXiv:2109.12132. Bibcode:2021ApJ...923..144P. doi:10.3847/1538-4357/ac29be.
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