Astronomy:HD 4308

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Short description: Star in the constellation Tucana
HD 4308
Observation data
Equinox J2000.0]] (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[2] mas/yr
Dec.: −741.913[2] mas/yr
Parallax (π)45.3559 ± 0.0178[2] mas
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, HD 4308, HIP 3497, SAO 248244, PPM 352003, LFT 71, LHS 1139, LPM 40, LTT 416, TYC 8847-598-1, 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

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

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

References

  1. ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A  XHIP record for this object at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Fuhrmann, K. et al. (2017). "Multiplicity among Solar-type Stars". The Astrophysical Journal 836 (1): 139. doi:10.3847/1538-4357/836/1/139. Bibcode: 2017ApJ...836..139F. 
  4. ↑ 4.0 4.1 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. doi:10.1086/504637. Bibcode: 2006AJ....132..161G. 
  5. ↑ 5.0 5.1 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. doi:10.1111/j.1365-2966.2009.16182.x. Bibcode: 2010MNRAS.403.1949K. 
  6. ↑ 6.0 6.1 6.2 Cutri, R. M. et al. (June 2003). 2MASS All Sky Catalog of point sources. NASA/IPAC. Bibcode: 2003tmc..book.....C. 
  7. ↑ 7.0 7.1 Soubiran, C. et al. (April 2013). "The catalogue of radial velocity standard stars for Gaia. I. Pre-launch release". Astronomy & Astrophysics 552: 11. doi:10.1051/0004-6361/201220927. A64. Bibcode: 2013A&A...552A..64S. 
  8. ↑ 8.0 8.1 8.2 Bonfanti, A. et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics 575: A18. doi:10.1051/0004-6361/201424951. Bibcode: 2015A&A...575A..18B. http://www.aanda.org/articles/aa/full_html/2015/03/aa24951-14/aa24951-14.html. 
  9. ↑ 9.0 9.1 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. doi:10.3847/1538-4357/833/2/161. 161. Bibcode: 2016ApJ...833..161G. 
  10. ↑ 10.0 10.1 "HD 4308". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+4308. 
  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. doi:10.1051/0004-6361/200811328. Bibcode: 2009A&A...497..563N. 
  12. ↑ 12.0 12.1 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. doi:10.1051/0004-6361:20054084. Bibcode: 2006A&A...447..361U. http://www.aanda.org/articles/aa/full/2006/07/aa4084-05/aa4084-05.html. 
  13. ↑ 13.0 13.1 "Hidden Companions of the Early Milky Way I. New alpha-Enhanced Exoplanet Hosts". December 2025. arXiv:2512.17072 [astro-ph.EP].

Coordinates: Sky map 00h 44m 39.2677s, −65° 38′ 58.280″



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