Summary
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]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| 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 mas[1] |
| Distance | 71.85 ± 0.03 ly (22.03 ± 0.01 pc) |
| Details[7] | |
| Mass | 0.95±0.05 M☉ |
| Radius | 1.04±0.03 R☉ |
| Luminosity | 1.03±0.01 L☉ |
| Surface gravity (log g) | 4.38±0.02 cgs |
| Temperature | 5,714±61 K |
| Metallicity [Fe/H] | −0.35±0.07[2] dex |
| Rotational velocity (v sin i) | 1.0±1.0[2] km/s |
| Age | 1.6±4.0[7] or 10.0+0.5 −1.0[8] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
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 edit
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]
| 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 edit
References edit
- ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d e f 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.
- ^ a b 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.
- ^ a b 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.
- ^ a b c Cutri, R. M.; et al. (June 2003). 2MASS All Sky Catalog of point sources. NASA/IPAC. Bibcode:2003tmc..book.....C.
- ^ a b 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.
- ^ a b c d 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.
- ^ a b 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.
- ^ a b "HD 4308". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-05.
- ^ 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.
- ^ a b 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.
External links edit
- "HD 4308". Exoplanets. Archived from the original on 2016-03-03. Retrieved 2009-05-23.