LP 791-18

Last updated
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]
Distance 86.92 ± 0.09  ly
(26.65 ± 0.03  pc)
Details [3]
Mass 0.139±0.005  M☉
Radius 0.17±0.018  R☉
Temperature 2960±55  K
Metallicity [Fe/H]-0.09±0.19  dex
Age 0.5±0.064  Gyr
Other designations
LP 791-18, TOI-736, TIC 181804752, 2MASS J11024596-1624222 [4]
Database references
SIMBAD data

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]

Contents

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 LP 791-18d.jpg
Artist's impression of LP 791-18 d, with c in the background

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 [a]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b—0.00978±0.000120.9479981±0.0000021—88.37+0.94
−0.95 ° 		1.212+0.059
−0.058  R🜨
d0.91±0.19  M🜨 0.01992±0.000142.753436±0.0000130.0011+0.0010
−0.0008		89.34±0.41° 1.032+0.044
−0.043  R🜨
c7.16±0.65  M🜨 0.02961+0.00035
−0.00036		4.9899100+0.0000012
−0.0000014		0.0001±0.000189.94±0.05° 2.488±0.096  R🜨

Notes

  1. ↑ Planet b: Peterson et al. (2021) [5]
    Semi-major axes: Peterson et al. (2021) [5]
    Planet c: Greklek-McKeon et al. (2025) [8]
    Planet d's mass and eccentricity: Greklek-McKeon et al. (2025); [8] miscellaneous properties from Peterson et al. (2021). [5]

References

  1. ↑ "Finding the constellation which contains given sky coordinates". djm.cc. 2 August 2008.
  2. 1 2 3 4 5 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. 1 2 3 4 5 6 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. 1 2 3 4 5 6 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. Bibcode:2023Natur.617..701P. doi:10.1038/s41586-023-05934-8. hdl: 11603/28165 . PMID   37198481.
  6. 1 2 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 .
  8. 1 2 Greklek-McKeon, Michael; Knutson, Heather A.; Levine, W. Garrett; Hu, Renyu; Saidel, Morgan; Barrientos, Jonathan Gomez; Batygin, Konstantin; Benneke, Björn (2025-01-30). "Updated Mass, Eccentricity, and Tidal Heating Constraints for the Earth-sized Planet LP 791-18". arXiv: 2501.18700 [astro-ph.EP].
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