Astronomy:HD 4308

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Short description: Star in the constellation Tucana
HD 4308
Observation data
Equinox J2000.0]] (ICRS)
Constellation Tucana
Right ascension  00h 44m 39.2675s[1]
Declination –65° 38′ 58.2825″[1]
Apparent magnitude (V) 6.544±0.005[2]
Characteristics
Evolutionary stage main sequence
Spectral type G6VFe-0.9[3]
Apparent magnitude (B) 7.193[4]
Apparent magnitude (V) 6.552[4]
Apparent magnitude (J) 5.366±0.024[5]
Apparent magnitude (H) 5.101±0.016[5]
Apparent magnitude (K) 4.945±0.020[5]
Astrometry
Radial velocity (Rv)+95.251±0.0162[6] km/s
Proper motion (μ) RA: 157.504±0.041[1] mas/yr
Dec.: −741.599±0.040[1] mas/yr
Parallax (π)45.3930 ± 0.0220[1] mas
Distance71.85 ± 0.03 ly
(22.03 ± 0.01 pc)
Details[7]
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[2] dex
Rotational velocity (v sin i)1.0±1.0[2] km/s
Age1.6±4.0[7] or 10.0+0.5
−1.0[8] Gyr
Other designations
BD−27°223, GC 897, GJ 9028, HD 4308, HIP 3497, SAO 248244, PPM 352003, LFT 71, LHS 1139, LPM 40, LTT 416, TYC 8847-598-1, 2MASS J00443925-6538581[9]
Database references
SIMBADdata
ARICNSdata
Extrasolar Planets
Encyclopaedia		data

HD 4308 is a single[2] star with an orbiting exoplanet in the southern constellation of Tucana.[9] 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.[2] This object is located at a distance of 72 light years, as determined from parallax measurements. It is a population II star[2] and is considered to be a member of the thick disk.[10] The star is receding from the Sun with a radial velocity of +95 km/s.[6]

This is a Sun-like G-type main-sequence star with a stellar classification of G6VFe-0.9,[3] 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[7] billion years up to 10 billion.[8] 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.[7]

Planetary system

In 2005, a low-mass planet 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.[11]

The HD 4308 planetary system[11]
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 — —

See also

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 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. 
  3. ↑ 3.0 3.1 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. 
  4. ↑ 4.0 4.1 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. 
  5. ↑ 5.0 5.1 5.2 Cutri, R. M. et al. (June 2003). 2MASS All Sky Catalog of point sources. NASA/IPAC. Bibcode: 2003tmc..book.....C. 
  6. ↑ 6.0 6.1 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. 
  7. ↑ 7.0 7.1 7.2 7.3 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. 
  8. ↑ 8.0 8.1 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. 
  9. ↑ 9.0 9.1 "HD 4308". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+4308. 
  10. ↑ 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. 
  11. ↑ 11.0 11.1 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. 

External links

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



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