LP 890-9

LP 890-9
Observation data; EpochJ2000EquinoxJ2000
Constellation	Eridanus
Right ascension	04h16m31.16176s
Declination	−28° 18′ 52.9543″
Apparent magnitude(V)	18.0±0.2
Characteristics
Evolutionary stage	Main sequence
Spectral type	M6V
Apparent magnitude(V)	18.0±0.2
Apparent magnitude(G)	15.791±0.003
Apparent magnitude(J)	12.258±0.023
Apparent magnitude(H)	11.692±0.025
Apparent magnitude(K)	11.344±0.023
Astrometry
Radial velocity(Rv)	28.84±2.84km/s
Proper motion(μ)	RA:218.569mas/yr; Dec.:−251.145mas/yr
Parallax(π)	30.9326 ± 0.0418mas
Distance	105.4 ± 0.1ly; (32.33 ± 0.04pc)
Absolute magnitude(MV)	15.45±0.2
Details
Mass	0.118±0.002M☉
Radius	0.1532+0.0048; −0.0024R☉
Luminosity (bolometric)	0.001438±0.000037L☉
Surface gravity(logg)	5.139+0.013; −0.028cgs
Temperature	2871+32; −45K
Metallicity[Fe/H]	−0.028±0.089dex
Age	7.2+2.2; −3.1Gyr
Other designations
	SPECULOOS-2,LP890-9,NLTT12925,TOI-4306,TIC44898913,2MASSJ04163114-2818526,WISEAJ041631.33-281855.5
Database references
SIMBAD	data

LP 890-9,also known asSPECULOOS-2orTOI-4306,is a high proper motionred dwarfstar located 105light-years(32pc) away from theSolar Systemin the constellation ofEridanus.The star has 12% the mass and 15% the radius of theSun,and a temperature of 2,871K(2,598°C;4,708°F). It is extremely faint and, with anapparent magnitudeof 18, is the faintest star with exoplanets discovered by theTransiting Exoplanet Survey Satellite.^[6]

Planetary system

In 2022, twoexoplanetswere discovered in orbit around this star. The first planet, LP 890-9 b, was initially identified usingTESS.Further observations usingSPECULOOSconfirmed this planet and discovered a second planet, LP 890-9 c. Both planets are likelyterrestrial planets,somewhat larger than Earth. The outer planet LP 890-9 c orbits within thehabitable zone,and is a favorable target for atmospheric characterization usingJWST.^[3]^[7]

LP 890-9 c orbits near the inner edge of the conservative habitable zone, and models differ as to whether the planet is more likely to resembleEarthorVenus.Spectra from JWST should make it possible to distinguish between these two scenarios.^[4]The planet is tidally locked.^[8]While the planet's location in the habitable zone suggests a strong possibility of an Earth-like atmosphere and climate, the planet's large size may count against its habitability. In addition, the planet is close enough to its star that powerful radiation may reduce its habitability.^[9]

The LP 890-9 planetary system^[3]
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	<13.2 $M$ _🜨	0.01875±0.00010	2.7299025+0.0000034 −0.0000040	—	89.67+0.22 −0.33°	1.320+0.053 −0.027 $R$ _🜨
c	<25.3 $M$ _🜨	0.03984±0.00022	8.457463±0.000024	—	89.287+0.026 −0.047°	1.367+0.055 −0.039 $R$ _🜨

Notes

^Theabsolute magnitudeM_Vof the star can be calculated from its apparent magnitudem_Vand distancedusing the following equation: $\scriptstyle M_{V}=m_{V}-5\log _{10}\left({\frac {d}{10\mathrm {\ parsecs} }}\right)$

References

^"Finding the constellation which contains given sky coordinates".djm.cc.2 August 2008.Retrieved7 September2022.
^^a ^b ^c ^d ^e ^fVallenari, A.; et al. (Gaia collaboration) (2023)."GaiaData 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 sourceatVizieR.
^^a ^b ^c ^d ^e ^f ^g ^hDelrez, L.; Murray, C. A.; et al. (September 2022). "Two temperate super-Earths transiting a nearby late-type M dwarf".Astronomy & Astrophysics.667:A59.arXiv:2209.02831.Bibcode:2022A&A...667A..59D.doi:10.1051/0004-6361/202244041.S2CID 252110654.
^^a ^bKaltenegger, L.; Payne, R. C.; et al. (September 2023)."Hot Earth or Young Venus? A nearby transiting rocky planet mystery".Monthly Notices of the Royal Astronomical Society: Letters.524(1): L10–L14.arXiv:2209.03105.Bibcode:2023MNRAS.524L..10K.doi:10.1093/mnrasl/slad064.
^"LP 890-9".SIMBAD.Centre de données astronomiques de Strasbourg.Retrieved7 September2022.
^"Planetary Systems".exoplanetarchive.ipac.caltech.edu.Retrieved2024-02-18.
^"SPECULOOS discovers a potentially habitable super-Earth".University of Liège.7 September 2022.Retrieved7 September2022.
^"Two potentially habitable super-Earth planets have been discovered".New Scientist.2022.Retrieved8 September2022.
^"Astronomers spot 2 intriguing alien worlds around ultracool star".Space.7 September 2022.Retrieved8 September2022.

[absmag-5] Theabsolute magnitudeM_Vof the star can be calculated from its apparent magnitudem_Vand distancedusing the following equation: $\scriptstyle M_{V}=m_{V}-5\log _{10}\left({\frac {d}{10\mathrm {\ parsecs} }}\right)$

[1] "Finding the constellation which contains given sky coordinates".djm.cc.2 August 2008.Retrieved7 September2022.

[GaiaDR3-2] Vallenari, A.; et al. (Gaia collaboration) (2023)."GaiaData 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 sourceatVizieR.

[Delrez2022-3] ^^a ^b ^c ^d ^e ^f ^g ^hDelrez, L.; Murray, C. A.; et al. (September 2022). "Two temperate super-Earths transiting a nearby late-type M dwarf".Astronomy & Astrophysics.667:A59.arXiv:2209.02831.Bibcode:2022A&A...667A..59D.doi:10.1051/0004-6361/202244041.S2CID 252110654.

[Kaltenegger2022-4] Kaltenegger, L.; Payne, R. C.; et al. (September 2023)."Hot Earth or Young Venus? A nearby transiting rocky planet mystery".Monthly Notices of the Royal Astronomical Society: Letters.524(1): L10–L14.arXiv:2209.03105.Bibcode:2023MNRAS.524L..10K.doi:10.1093/mnrasl/slad064.

[SIMBAD-6] "LP 890-9".SIMBAD.Centre de données astronomiques de Strasbourg.Retrieved7 September2022.

[7] "Planetary Systems".exoplanetarchive.ipac.caltech.edu.Retrieved2024-02-18.

[ULiège-8] "SPECULOOS discovers a potentially habitable super-Earth".University of Liège.7 September 2022.Retrieved7 September2022.

[9] "Two potentially habitable super-Earth planets have been discovered".New Scientist.2022.Retrieved8 September2022.

[10] "Astronomers spot 2 intriguing alien worlds around ultracool star".Space.7 September 2022.Retrieved8 September2022.

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[note 1]

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Observation data Epoch J2000 Equinox J2000
Constellation	Eridanus^[1]
Right ascension	04^h16^m31.16176^s^[2]
Declination	−28° 18′ 52.9543″^[2]
Apparent magnitude(V)	18.0±0.2^[3]
Characteristics
Evolutionary stage	Main sequence
Spectral type	M6V^[4]
Apparent magnitude(V)	18.0±0.2^[3]
Apparent magnitude(G)	15.791±0.003^[2]
Apparent magnitude(J)	12.258±0.023^[3]
Apparent magnitude(H)	11.692±0.025^[3]
Apparent magnitude(K)	11.344±0.023^[3]
Astrometry

Radial velocity(R_v)	28.84±2.84^[2]km/s
Proper motion(μ)	RA:218.569mas/yr^[2] Dec.:−251.145mas/yr^[2]
Parallax(π)	30.9326 ± 0.0418mas^[2]
Distance	105.4 ± 0.1ly (32.33 ± 0.04pc)
Absolute magnitude(M_V)	15.45±0.2^{[note 1]}

Details^[3]

Mass	0.118±0.002`M`_☉
Radius	0.1532+0.0048 −0.0024`R`_☉
Luminosity (bolometric)	0.001438±0.000037`L`_☉
Surface gravity(logg)	5.139+0.013 −0.028cgs
Temperature	2871+32 −45K
Metallicity[Fe/H]	−0.028±0.089dex
Age	7.2+2.2 −3.1Gyr

Other designations
SPECULOOS-2,LP890-9,NLTT12925,TOI-4306,TIC44898913,2MASSJ04163114-2818526,WISEAJ041631.33-281855.5^[5]
Database references
SIMBAD	data

Planetary system

See also

Notes

References