Gliese 393

Gliese 393, or GJ 393, is a single[7] star in the equatorial constellation of Sextans, positioned about 1.5° to the NNW of Beta Sextantis.[8] At an apparent visual magnitude of 9.65,[2] it is much too faint to be seen with the unaided eye. This star is located at a distance of 22.9 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +8.3 km/s.[2] It has a large proper motion, traversing the celestial sphere at the rate of 0.950″ per year.[9] The net velocity of this star relative to the Sun is 32.9 km/s.[2] It shares a similar space motion as members of the AB Doradus moving group, but is considered a random interloper.[5]

Gliese 393
Observation data
Epoch J2000      Equinox J2000
Constellation Sextans
Right ascension 10h 28m 55.55130s[1]
Declination +00° 50′ 27.6018″[1]
Apparent magnitude (V) 9.65[2]
Characteristics
Spectral type M2V[3]
U−B color index 1.192[2]
B−V color index 1.507±0.014[2]
Astrometry
Radial velocity (Rv)+8.34±0.10[2] km/s
Proper motion (μ) RA: −603.003[1] mas/yr
Dec.: −732.075[1] mas/yr
Parallax (π)142.0951 ± 0.0212 mas[4]
Distance22.953 ± 0.003 ly
(7.038 ± 0.001 pc)
Absolute magnitude (MV)10.40[2]
Details[3]
Mass0.432±0.011 M☉
Radius0.4459±0.0073 R☉
Luminosity0.02687±0.00054 L☉
Surface gravity (log g)4.88±0.07 cgs
Temperature3,579±51 K
Metallicity [Fe/H]−0.09±0.16 dex
Rotational velocity (v sin i)1.5[5] km/s
Other designations
BD+01°2447, GJ 393, HIP 51317, LTT 12805, 2MASS J10285555+0050275[6]
Database references
SIMBADdata

The stellar classification of GJ 393 is M2V,[3] indicating this is a small red dwarf star that is generating energy through core hydrogen fusion. It is rotating slowly and appears to be chromospherically inactive, suggesting it is an older star; perhaps as much as 10 billion years old.[5] The star has 43% of the mass of the Sun and 44.6% of the Sun's radius. The metallicity, what astronomers term the abundance of heavy elements, is lower than in the Sun. It is radiating just 2.7% of the Sun's luminosity from its photosphere at an effective temperature of 3,579 K.[3]

Planetary system

In 2019, one candidate planet was detected by the radial velocity method. It is classified as a hot super-Earth, with an orbital period of one week and a semimajor axis of 8.2 Gm. Longer period signals found in the data were interpreted as stellar activity.[10]

In 2021, the planet was confirmed as real after being detected independently in three different datasets.[11]

The Gliese 393 planetary system[10][11]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 1.71±0.24 M🜨 0.05402±0.00072 7.0268±0.00082 0 — —

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644
  3. Schweitzer, A.; et al. (May 2019). "The CARMENES search for exoplanets around M dwarfs. Different roads to radii and masses of the target stars". Astronomy & Astrophysics. 625: 16. arXiv:1904.03231. Bibcode:2019A&A...625A..68S. doi:10.1051/0004-6361/201834965. S2CID 102351979. A68.
  4. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  5. Schaefer, G. H.; et al. (May 2018), "AB Dor Moving Group Stars Resolved with the CHARA Array", The Astrophysical Journal, 858 (2): 14, Bibcode:2018ApJ...858...71S, doi:10.3847/1538-4357/aaba71, S2CID 48362791, 71
  6. "GJ 393". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-08.
  7. Winters, Jennifer G.; et al. (June 2019). "The Solar Neighborhood. XLV. The Stellar Multiplicity Rate of M Dwarfs Within 25 pc". The Astronomical Journal. 157 (6): 32. arXiv:1901.06364. Bibcode:2019AJ....157..216W. doi:10.3847/1538-3881/ab05dc. S2CID 86859146. 216.
  8. Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. Vol. 2. Sky Publishing Corporation and the European Space Agency. p. 779. ISBN 0-933346-83-2.
  9. Lépine, Sébastien; Shara, Michael M. (March 2005). "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)". The Astronomical Journal. 129 (3): 1483–1522. arXiv:astro-ph/0412070. Bibcode:2005AJ....129.1483L. doi:10.1086/427854. S2CID 2603568.
  10. Barnes, J. R.; et al. (2019-06-11). "Frequency of planets orbiting M dwarfs in the Solar neighbourhood". arXiv:1906.04644 [astro-ph.EP].
  11. Amado, Pedro J.; Bauer, Florian F.; Rodríguez López, Cristina; Rodríguez, Eloy; Cardona Guillén, C.; Perger, M.; Caballero, José A.; López-González, Maria J.; Muñoz Rodríguez, I.; Pozuelos, F. J.; Sánchez-Rivero, A.; Schlecker, M.; Quirrenbach, Andreas; Ribas, Ignasi; Reiners, Ansgar; Almenara, J.; Astudillo-Defru, N.; Azzaro, M.; Béjar, Victor J. S.; Bohemann, R.; Bonfils, X.; Bouchy, F.; Cifuentes, C.; Cortés-Contreras, M.; Delfosse, Xavier; Dreizler, Stefan; Forveille, Thierry; Hatzes, Artie P.; Henning, Thomas K.; Jeffers, Sandra V.; Kaminski, Adrian; Kürster, Martin; Lafarga, M.; Lodieu, Nicolas; Lovis, C.; Mayor, M.; Montes, David; Morales, Juan Carlos; Morales, Nicolás; Murgas, F.; Ortiz, José L.; Pepe, F.; Perdelwitz, V.; Pollaco, D.; Santos, N. C.; Schöfer, P.; Schweitzer, A.; Ségransan, N. C.; Shan, Y.; Stock, S.; Tal-Or, Lev; Udry, S.; Zapatero-Osorio, María Rosa; Zechmeister, Mathias (2021-05-28). "The CARMENES search for exoplanets around M dwarfs". Astronomy & Astrophysics. 650: A188. arXiv:2105.13785. doi:10.1051/0004-6361/202140633. S2CID 235248027.
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