LHS 475
 Artist's impression of LHS 475 b and its host star | |
| Observation data EpochJ2000EquinoxJ2000 | |
|---|---|
| Constellation | Octans[1] |
| Right ascension | 19h20m54.37612s[2] |
| Declination | −82° 33′ 16.1679″[2] |
| Apparent magnitude(V) | 12.69[3] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | M3.5V[4] |
| Apparent magnitude(V) | 12.69±0.03[3] |
| Apparent magnitude(G) | 11.413±0.003[2] |
| Apparent magnitude(J) | 8.555±0.030[3] |
| Apparent magnitude(H) | 8.004±0.038[3] |
| Apparent magnitude(K) | 7.686±0.042[3] |
| Astrometry | |
| Radial velocity(Rv) | −10.59±0.24[2]km/s |
| Proper motion(μ) | RA:+342.300mas/yr[2] Dec.:−1230.297mas/yr[2] |
| Parallax(π) | 80.1134 ± 0.0206mas[2] |
| Distance | 40.71 ± 0.01ly (12.482 ± 0.003pc) |
| Details[3] | |
| Mass | 0.274±0.015M☉ |
| Radius | 0.2789±0.0014[4]R☉ |
| Luminosity (bolometric) | 0.00862±0.00039L☉ |
| Surface gravity(logg) | 4.964±0.046cgs |
| Temperature | 3289±83K |
| Rotation | 79.317d |
| Other designations | |
| Database references | |
| SIMBAD | data |
LHS 475is ared dwarfstar located 40.7light-years(12.5parsecs) away from theSolar Systemin the constellation ofOctans.It hosts one knownexoplanet.[6][7]
Planetary system
[edit]
The exoplanetLHS 475 bwas initially found intransitdata fromTESS,and its confirmation using theNIRSpecinstrument of theJames Webb Space Telescope,which also observed itstransmission spectrum,was published in January 2023.[7]Another independent confirmation of the planet was published onarXivin April 2023, and a year later accepted to theAstronomical Journal.[3]
The JWST data is consistent with a featureless spectrum, as would be expected of a planet with no atmosphere, but is also consistent with some types of atmosphere, such as a thincarbon dioxide-dominated atmosphere like that of Mars, or an atmosphere obscured by a thick cloud deck such as that of Venus.[4]Other atmospheric compositions, such as amethane-dominated atmosphere, are ruled out by this spectrum.[6]
LHS 475 b is close in size to Earth, at 99% its diameter, but is much hotter, with anequilibrium temperatureof 586 K (313 °C; 595 °F). Assuming the planet has little to no atmosphere, its dayside temperature is estimated at 748 K (475 °C; 887 °F). The planet completes an orbit around its star in just two days and is likelytidally locked.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 0.914±0.187[note 1]M🜨 | 0.02037(37) | 2.0291010(17) | 0 | 87.38±0.19° | 0.991±0.050R🜨 |
Notes
[edit]- ^The mass of this planet has not been measured; this value is an estimate.
References
[edit]- ^"Finding the constellation which contains given sky coordinates".djm.cc.2 August 2008.
- ^abcdefVallenari, 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.S2CID244398875. Gaia DR3 record for this sourceatVizieR.
- ^abcdefghMent, Kristo; Charbonneau, David; et al. (May 2024)."LHS 475 b: A Potential Venus Analog Orbiting a Nearby M Dwarf".The Astronomical Journal.167(5): 197.arXiv:2304.01920.Bibcode:2024AJ....167..197M.doi:10.3847/1538-3881/ad1b58.
- ^abcdeLustig-Yaeger, J.; Fu, G.; et al. (January 2023). "A JWST transmission spectrum of the nearby Earth-sized exoplanet LHS 475 b".Nature Astronomy.7(11): 1317–1328.arXiv:2301.04191.Bibcode:2023NatAs...7.1317L.doi:10.1038/s41550-023-02064-z.S2CID261439142.
- ^"LHS 475".SIMBAD.Centre de données astronomiques de Strasbourg.Retrieved12 January2023.
- ^ab"NASA's Webb Confirms Its First Exoplanet".NASA.11 January 2023.Retrieved12 January2023.
- ^abChow, Denise (11 January 2023)."James Webb Telescope finds its first exoplanet - The planet is almost the same size as Earth, according to a research team led by astronomers at the Johns Hopkins University Applied Physics Laboratory".NBC News.Retrieved12 January2023.
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