GJ 2030

GJ 2030

Observation data Epoch J2000       Equinox J2000
Constellation	Eridanus [1]
Right ascension	03h 23m 17.70116s [2]
Declination	−07° 47′ 38.7554″ [2]
Apparent magnitude  (V)	6.206±0.003 [3]
Characteristics
Evolutionary stage	subgiant [2]
Spectral type	G5/6V [4]
Astrometry
Radial velocity (Rv)	+41.67±0.16 [2] km/s
Proper motion (μ)	RA: +1.295 mas/yr [2] Dec.: −219.292 mas/yr [2]
Parallax (π)	26.7913±0.0912  mas [2]
Distance	121.7 ± 0.4  ly (37.3 ± 0.1  pc)
Absolute magnitude  (MV)	+3.35 [1]
Details [5]
Mass	1.022±0.024  M☉
Radius	2.429±0.061  R☉
Luminosity	4.064±0.043  L☉
Surface gravity (log g)	3.73±0.12  cgs
Temperature	5,259±66  K
Metallicity [Fe/H]	−0.45±0.02  dex
Age	6.39 [6]   Gyr
Other designations
BD−08°643, GJ 2030, HD 21019, HIP 15776, HR 1024, TYC 5295-1155-1 [7]
Database references
SIMBAD	data
Exoplanet Archive	data

GJ 2030 is a star in the constellation Eridanus. At an apparent magnitude of +6.206, ^[3] it is close to the average threshold for naked eye visibility, and can only be viewed from sufficiently dark skies, far from light pollution. ^[8] Parallax measurements by the Gaia spacecraft measured a distance of 121.7 light-years, give or take 0.4 light-years. ^[2]

The spectrum of this star matches a spectral class of G5/6V, ^[4] with the luminosity class V suggesting it is a main sequence star, but its physical properties suggest it is actually a subgiant. ^[2] It has 1.02 times the Sun's mass and 2.43 times the Sun's radius. It radiates 4.06 times the Sun's luminosity from its photosphere at an effective temperature of 5,259  K. ^[5] At this temperature, the star shines with a yellowish color typical of G-type stars. ^[9]

GJ 2030 is likely a member of the thick disk population, ^[10] with a substantially lower metallicity than the Sun. ^[5] Its age is estimated at 6.39 billion years, older than the Solar System. ^[6]

Planetary system

Two extrasolar planets were discovered around the star in 2022, detected via Doppler spectroscopy (radial velocity method) and astrometry. ^[11]

The GJ 2030 planetary system ^[11]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (years)	Eccentricity	Inclination	Radius
b	≥0.015±0.002  MJ	0.034+0.001 −0.002	0.0065196±0.0000004	0.239+0.075 −0.058	—	—
c	12.803+2.335 −2.136  MJ	16.761+1.294 −1.337	69.91+6.36 −7.00	0.041+0.003 −0.008	16.999+2.935 −2.535 °	—

References

1. 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. XHIP record for this object at VizieR.
2. 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.
3. Paunzen, E. (August 2015). "A new catalogue of Strömgren-Crawford uvbyβ photometry". Astronomy and Astrophysics. 580: A23. arXiv: 1506.04568 . Bibcode:2015A&A...580A..23P. doi:10.1051/0004-6361/201526413. ISSN   0004-6361.
4. Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey. 5: 0. Bibcode:1999MSS...C05....0H.
5. Soubiran, C.; et al. (2024-02-01). "Gaia FGK benchmark stars: Fundamental Teff and log g of the third version". Astronomy and Astrophysics. 682: A145. arXiv: 2310.11302 . Bibcode:2024A&A...682A.145S. doi:10.1051/0004-6361/202347136. ISSN   0004-6361.
6. Casagrande, L.; Schönrich, R.; Asplund, M.; Cassisi, S.; Ramírez, I.; Meléndez, J.; Bensby, T.; Feltzing, S. (June 2011). "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey". Astronomy and Astrophysics. 530: A138. arXiv: 1103.4651 . Bibcode:2011A&A...530A.138C. doi:10.1051/0004-6361/201016276. ISSN   0004-6361.
7. "GJ 2030". SIMBAD . Centre de données astronomiques de Strasbourg.
8. "Limiting Magnitude | COSMOS". astronomy.swin.edu.au. Retrieved 2025-06-01.
9. "The Colour of Stars". Australia Telescope, Outreach and Education. Commonwealth Scientific and Industrial Research Organisation. December 21, 2004. Archived from the original on 2013-12-03. Retrieved 2012-01-16.
10. Horch, Elliott P.; van Belle, Gerard T.; Davidson, James W.; Ciastko, Lindsay A.; Everett, Mark E.; Bjorkman, Karen S. (November 2015). "Observations of Binary Stars with the Differential Speckle Survey Instrument. VI. Measures during 2014 at the Discovery Channel Telescope". The Astronomical Journal. 150 (5): 151. arXiv: 1509.03498 . Bibcode:2015AJ....150..151H. doi:10.1088/0004-6256/150/5/151. ISSN   0004-6256.
11. Feng, Fabo; Butler, R. Paul; et al. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". The Astrophysical Journal Supplement Series . 262 (21): 21. arXiv: 2208.12720 . Bibcode:2022ApJS..262...21F. doi: 10.3847/1538-4365/ac7e57 . S2CID   251864022.