Gliese 625
Observation data
Epoch J2000      Equinox J2000
Constellation Draco
Right ascension 16h 25m 24.62304s[1]
Declination +54° 18′ 14.7655″[1]
Apparent magnitude (V) 10.13[2]
Characteristics
Spectral type M1.5V[3]
B−V color index 1.591±0.027[2]
Astrometry
Radial velocity (Rv)−13.37±0.14[1] km/s
Proper motion (μ) RA: 432.230(19) mas/yr[1]
Dec.: −171.652(22) mas/yr[1]
Parallax (π)154.3503 ± 0.0161 mas[1]
Distance21.131 ± 0.002 ly
(6.4788 ± 0.0007 pc)
Absolute magnitude (MV)11.06[2]
Details
Mass0.240±0.013[4] M☉
Radius0.255±0.034[4] R☉
Luminosity0.01482±0.00022[5] L☉
Surface gravity (log g)4.94±0.06[6] cgs
Temperature3,557±9[7] K
Metallicity [Fe/H]−0.401±0.005[7] dex
Rotation77.8±5.5 d[6]
Rotational velocity (v sin i)2.2±0.7[7] km/s
Other designations
GJ 625, HIP 80459, AC +54 1646, G 202-48, G 226-7, G 225-62, LSPM J1625+5418, NLTT 42804, PLX 3740.03, TYC 3878-1193-1, 2MASS J16252459+5418148[8]
Database references
SIMBADdata

GJ 625 (AC 54 1646-56) is a small red dwarf star with an exoplanetary companion in the northern constellation of Draco. The system is located at a distance of 21.1 light-years from the Sun based on parallax,[1] but is drifting closer with a radial velocity of −13 km/s.[7] It is too faint to be visible to the naked eye, having an apparent visual magnitude of 10.13[2] and an absolute magnitude of 11.06.[2]

This is an M-type main-sequence star with a stellar classification of M1.5V.[3] It is spinning slowly with a rotation period of roughly 78 days, and has a low magnetic activity level.[6] The star has about a quarter of the mass and size of the Sun,[4] and the metal content is 40% the abundances in the Sun's atmosphere. It is radiating just 1.5% of the luminosity of the Sun from its photosphere at an effective temperature of 3,557 K.[7]

Planetary system

On May 18, 2017, a planet was detected orbiting GJ 625 by the HARPS-N telescope. The planet, GJ 625 b, orbits near the inner edge of the optimistic circumstellar habitable zone of its star, and the discoverers speculate it may support liquid water, depending on atmospheric conditions.[6] Based on the habitable zone model of Kopparapu et al. 2013, the planet is not considered to be in the habitable zone as it would likely experience a runaway greenhouse effect, similar to Venus.[9][10][11][12]

Since the star is considered quiescent (having a low X-ray emission and flare rate), the radio emission from the system may be auroral in nature and coming from a short-period planet. Further observations will be needed to confirm this.[13]

The Gliese 625 planetary system[6]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b ≥2.82±0.51 M🜨 0.078361+0.000044
−0.000046 		14.628+0.012
−0.013 		0.13+0.12
−0.09 		— —

References

  1. ^ a b c d e f 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.
  2. ^ a b c d e 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. ^ a b Alonso-Floriano, F. J.; et al. (May 2015). "CARMENES input catalogue of M dwarfs. I. Low-resolution spectroscopy with CAFOS". Astronomy & Astrophysics. 577: 19. arXiv:1502.07580. Bibcode:2015A&A...577A.128A. doi:10.1051/0004-6361/201525803. S2CID 53135130. A128.
  4. ^ a b c Khata, Dhrimadri; et al. (April 2020). "Understanding the physical properties of young M dwarfs: NIR spectroscopic studies". Monthly Notices of the Royal Astronomical Society. 493 (3): 4533–4550. arXiv:2002.05762. Bibcode:2020MNRAS.493.4533K. doi:10.1093/mnras/staa427.
  5. ^ 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. VizieR entry
  6. ^ a b c d e Suárez Mascareño, A.; et al. (2017). "HADES RV Programme with HARPS-N at TNG. V. A super-Earth on the inner edge of the habitable zone of the nearby M dwarf GJ 625". Astronomy and Astrophysics. 605. A92. arXiv:1705.06537. Bibcode:2017A&A...605A..92S. doi:10.1051/0004-6361/201730957. S2CID 119003137.
  7. ^ a b c d e Fouqué, Pascal; et al. (April 2018). "SPIRou Input Catalogue: global properties of 440 M dwarfs observed with ESPaDOnS at CFHT". Monthly Notices of the Royal Astronomical Society. 475 (2): 1960–1986. arXiv:1712.04490. Bibcode:2018MNRAS.475.1960F. doi:10.1093/mnras/stx3246.
  8. ^ "G 202-48". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-11-21.
  9. ^ Kopparapu, Ravi Kumar; et al. (2013). "Habitable Zones Around Main-Sequence Stars: New Estimates". The Astrophysical Journal. 765 (2): 131. arXiv:1301.6674. Bibcode:2013ApJ...765..131K. doi:10.1088/0004-637X/765/2/131. S2CID 76651902.
  10. ^ Kopparapu, Ravi Kumar. "Calculation of Habitable Zones". Retrieved 20 November 2023.
  11. ^ "GJ 625". hzgallery.org. Retrieved 15 September 2022.
  12. ^ LePage, Andrew (22 May 2017). "Habitable Planet Reality Check: Is GJ 625b a Super-Earth or a Super-Venus?". drewexmachina.com. Retrieved 15 September 2022.
  13. ^ Pope, Benjamin J. S.; et al. (September 2021). "The TESS View of LOFAR Radio-emitting Stars". The Astrophysical Journal Letters. 919 (1): 8. arXiv:2110.04759. Bibcode:2021ApJ...919L..10P. doi:10.3847/2041-8213/ac230c. S2CID 238583021. L10.


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