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HD 4308

Coordinates: Sky map 00h 44m 39.2677s, −65° 38′ 58.280″
From Wikipedia, the free encyclopedia
HD 4308
Observation data
Epoch J2000      Equinox ICRS
Constellation Tucana[1]
Right ascension 00h 44m 39.26721s[2]
Declination −65° 38′ 58.2777″[2]
Apparent magnitude (V) 6.544±0.005[3]
Characteristics
Evolutionary stage main sequence
Spectral type G6VFe-0.9[4]
Apparent magnitude (B) 7.193[5]
Apparent magnitude (V) 6.552[5]
Apparent magnitude (J) 5.366±0.024[6]
Apparent magnitude (H) 5.101±0.016[6]
Apparent magnitude (K) 4.945±0.020[6]
Astrometry
Radial velocity (Rv)+95.251±0.0162[7] km/s
Proper motion (μ) RA: +157.639 mas/yr[2]
Dec.: −741.913 mas/yr[2]
Parallax (π)45.3559±0.0178 mas[2]
Distance71.91 ± 0.03 ly
(22.048 ± 0.009 pc)
Absolute magnitude (MV)4.83[1]
Details[8]
Mass0.95±0.05 M☉
Radius1.04±0.03 R☉
Luminosity1.03±0.01 L☉
Surface gravity (log g)4.38±0.02 cgs
Temperature5,714±61 K
Metallicity [Fe/H]−0.35±0.07[3] dex
Rotational velocity (v sin i)1.0±1.0[3] km/s
Age10.0+0.5
−1.0[9] Gyr
Other designations
CD−66°38, GC 897, GJ 31.5, GJ 9028, HD 4308, HIP 3497, SAO 248244, PPM 352003, LFT 71, LHS 1139, LPM 40, LTT 416, TYC 8847-598-1, GCRV 50662, 2MASS J00443925-6538581[10]
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata

HD 4308 is a single[3] star with a planetary system in the southern constellation of Tucana.[10] It has a yellow hue and is a challenge to view with the naked eye even under good seeing conditions, having an apparent visual magnitude of 6.54.[3] This object is located at a distance of 72 light-years, as determined from parallax measurements. It is a population II star[3] and is considered to be a member of the thick disk.[11] The star is receding from the Sun with a radial velocity of +95 km/s.[7]

Stellar properties

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This is a Sun-like G-type main-sequence star with a stellar classification of G6VFe-0.9,[4] where the suffix notation indicates an underabundance of iron in the spectrum. The age of the star is poorly constrained, with estimated ranging from 1.6[8] billion years up to 10 billion.[9] It has 95% of the mass of the Sun but 104% of the Sun's radius. The star is radiating nearly the same luminosity as the Sun from its photosphere at an effective temperature of 5,714 K.[8]

Planetary system

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In 2005, a low-mass exoplanet was found in orbit around this star using the radial velocity method with the HARPS spectrograph. It is following a circular orbit close to its host star with a period of just 15.6 days. Unusual for a star with planets, HD 4308 has a metallicity lower than that of the Sun.[12] Further radial velocity observations allowed two additional planets to be detected by 2025.[13]

The HD 4308 planetary system[12][13]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination
(°)		 Radius
b ≥0.0442 MJ 0.115 15.56±0.02 0.00±0.01 — —
c ≥0.15±0.07 MJ — 850±25 0.47±0.34 — —
d ≥0.14±0.08 MJ — 1,500±60 0.37±0.30 — —

See also

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References

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  1. 1 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. XHIP record for this object at VizieR.
  2. 1 2 3 4 5 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. 1 2 3 4 5 6 Fuhrmann, K.; et al. (2017). "Multiplicity among Solar-type Stars". The Astrophysical Journal. 836 (1): 139. Bibcode:2017ApJ...836..139F. doi:10.3847/1538-4357/836/1/139.
  4. 1 2 Gray, R. O.; et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. S2CID 119476992.
  5. 1 2 Koen, C.; Kilkenny, D.; van Wyk, F.; Marang, F. (April 21, 2010). "UBV(RI)CJHK observations of Hipparcos-selected nearby stars". Monthly Notices of the Royal Astronomical Society. 403 (4): 1949–1968. Bibcode:2010MNRAS.403.1949K. doi:10.1111/j.1365-2966.2009.16182.x.
  6. 1 2 3 Cutri, R. M.; et al. (June 2003). 2MASS All Sky Catalog of point sources. NASA/IPAC. Bibcode:2003tmc..book.....C.
  7. 1 2 Soubiran, C.; et al. (April 2013). "The catalogue of radial velocity standard stars for Gaia. I. Pre-launch release". Astronomy & Astrophysics. 552: 11. arXiv:1302.1905. Bibcode:2013A&A...552A..64S. doi:10.1051/0004-6361/201220927. S2CID 56094559. A64.
  8. 1 2 3 Bonfanti, A.; et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics. 575. A18. arXiv:1411.4302. Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951. S2CID 54555839.
  9. 1 2 Ge, Z. S.; et al. (December 2016). "Ages of 70 Dwarfs of Three Populations in the Solar Neighborhood: Considering O and C Abundances in Stellar Models". The Astrophysical Journal. 833 (2): 13. arXiv:1612.01622. Bibcode:2016ApJ...833..161G. doi:10.3847/1538-4357/833/2/161. S2CID 119190116. 161.
  10. 1 2 "HD 4308". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-05.
  11. ↑ Neves, V.; et al. (April 2009). "Chemical abundances of 451 stars from the HARPS GTO planet search program. Thin disc, thick disc, and planets". Astronomy and Astrophysics. 497 (2): 563–581. arXiv:0902.3374. Bibcode:2009A&A...497..563N. doi:10.1051/0004-6361/200811328. S2CID 7907201.
  12. 1 2 Udry, S.; et al. (2006). "The HARPS search for southern extra-solar planets V. A 14 Earth-masses planet orbiting HD 4308". Astronomy and Astrophysics. 447 (1): 361–367. arXiv:astro-ph/0510354. Bibcode:2006A&A...447..361U. doi:10.1051/0004-6361:20054084. S2CID 119078261.
  13. 1 2 Ferreira, Thiago; Yana Galarza, Jhon; et al. (December 2025). "Hidden Companions of the Early Milky Way I. New alpha-Enhanced Exoplanet Hosts". arXiv:2512.17072 [astro-ph.EP].
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