Gliese 393, or GJ 393, is a single[7] star with an orbiting exoplanet companion 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]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sextans |
| Right ascension | 10h 28m 55.551s[1] |
| Declination | +00° 50′ 27.60″[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: −602.992 mas/yr[1] Dec.: −731.882 mas/yr[1] |
| Parallax (π) | 142.0951 ± 0.0212 mas[1] |
| Distance | 22.953 ± 0.003 ly (7.038 ± 0.001 pc) |
| Absolute magnitude (MV) | 10.40[2] |
| Details[3] | |
| Mass | 0.432±0.011 M☉ |
| Radius | 0.4459±0.0073 R☉ |
| Luminosity | 0.02687±0.00054 L☉ |
| Surface gravity (log g) | 4.88±0.07 cgs |
| Temperature | 3,579±51 K |
| Metallicity [Fe/H] | −0.09±0.16 dex |
| Rotation | 34.15±0.22 d[4] |
| Rotational velocity (v sin i) | 1.5[5] km/s |
| Age | 3.28[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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
editIn 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]
| 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 | 7.02679+0.00082 −0.00085 |
0 | — | — |
References
edit- ^ a b c d e 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.
- ^ a b c d e f g h 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
- ^ a b c d 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.
- ^ a b Engle, Scott G.; Guinan, Edward F. (September 2023). "Living with a Red Dwarf: The Rotation-Age Relationships of M Dwarfs". The Astrophysical Journal Letters. 954 (2): L50. arXiv:2307.01136. Bibcode:2023ApJ...954L..50E. doi:10.3847/2041-8213/acf472. L50.
- ^ a b c 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
- ^ "GJ 393". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-08.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ Barnes, J. R.; et al. (2019-06-11). "Frequency of planets orbiting M dwarfs in the Solar neighbourhood". arXiv:1906.04644 [astro-ph.EP].
- ^ a b Amado, Pedro J.; et al. (2021-05-28). "The CARMENES search for exoplanets around M dwarfs". Astronomy & Astrophysics. 650: A188. arXiv:2105.13785. Bibcode:2021A&A...650A.188A. doi:10.1051/0004-6361/202140633. S2CID 235248027.