HD 6434
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Phoenix[1] |
| Right ascension | 01h 04m 40.15027s[2] |
| Declination | −39° 29′ 17.5842″[2] |
| Apparent magnitude (V) | 7.71±0.12[3] |
| Characteristics | |
| Spectral type | G2/G3V[4] |
| B−V color index | 0.61±0.01[3] |
| Astrometry | |
| Radial velocity (Rv) | +23.14±0.12[2] km/s |
| Proper motion (μ) | RA: −170.033 mas/yr[2] Dec.: −527.946 mas/yr[2] |
| Parallax (π) | 23.6673±0.0251 mas[2] |
| Distance | 137.8 ± 0.1 ly (42.25 ± 0.04 pc) |
| Absolute magnitude (MV) | 4.69[5] |
| Details[6] | |
| Mass | 0.83±0.03 M☉ |
| Radius | 1.029±0.004 R☉ |
| Luminosity | 1.208±0.004 L☉ |
| Surface gravity (log g) | 4.31±0.01 cgs |
| Temperature | 5,907±71 K |
| Metallicity [Fe/H] | −0.48±0.05[3] dex |
| Rotation | 18.6 d[7] |
| Rotational velocity (v sin i) | 2.2±0.5[3] km/s |
| Age | 12.2±0.8 Gyr |
| Other designations | |
| Nenque, CD−40°239, GJ 9037, HD 6434, HIP 5054, SAO 192911, LFT 102, LHS 1188, LPM 57, LTT 610, GCRV 51158, 2MASS J01044015-3929173[8] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| ARICNS | data |
HD 6434, also named Nenque, is a star in the southern constellation of Phoenix. Yellow dwarfs such as this are not very luminous, so at a distance of 138 light-years it is not visible to the unaided eye. However, with binoculars it is readily visible under ideal observing conditions, having an apparent visual magnitude of 7.71.[3] The star is drifting further from the Sun with a radial velocity of +23 km/s.[2] It has one known planet, HD 6434 b.
Nomenclature
[edit]The designation HD 6434 comes from the Henry Draper Catalogue.
This was one of the systems selected to be named in the 2019 NameExoWorlds campaign during the 100th anniversary of the IAU, which assigned each country a star and planet to be named. This system was assigned to Ecuador. The approved names were Nenque for the star and Eyeke for the planet; Nenque means the Sun in the language spoken by the Indigenous Waorani people.[9][10]
Stellar properties
[edit]This object is a Sun-like G-type main-sequence star with a stellar classification of G2/G3V.[4] It is an ancient population II[11] star with an estimated age of 12[6] billion years, and is one of the most metal-deficient stars known to host a planet.[3] This star is spinning at a leisurely rate with a projected rotational velocity of 2.2 km/s.[3] It has 88% of the mass of the Sun but is nearly the same size. HD 6434 is radiating 1.2 times the luminosity of the Sun from its photosphere at an effective temperature of 5,907 K.[6]
HD 6434 is enriched in barium, implying the possible presence of a white dwarf companion that was formerly an asymptotic giant branch star. No white dwarf has been detected by Gaia, but a slight radial velocity trend suggests a possible companion (in addition to the known planet).[12]
Planetary system
[edit]In 2000, a planet, designated HD 6434 b, was detected in a close orbit around the star by the radial velocity method. It has a minimum mass about half that of Jupiter. The peer-reviewed scientific paper was published four years later.[13][7] Its name Eyeke means near in the Waorani language, referring to its proximity to its star.[9]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b / Eyeke | ≥0.44±0.01 MJ | 0.148±0.002 | 22.0170±0.0008 | 0.146±0.025 | — | — |
See also
[edit]References
[edit]- ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
- 1 2 3 4 5 6 7 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.
- 1 2 3 4 5 6 7 8 Hinkel, Natalie R.; et al. (2015). "A New Analysis of the Exoplanet Hosting System HD 6434". The Astronomical Journal. 150 (6). 169. arXiv:1510.01746. Bibcode:2015AJ....150..169H. doi:10.1088/0004-6256/150/6/169. S2CID 119219444.
- 1 2 White, Russel J.; Gabor, Jared M.; Hillenbrand, Lynne A. (June 2007). "High-Dispersion Optical Spectra of Nearby Stars Younger Than the Sun". The Astronomical Journal. 133 (6): 2524–2536. arXiv:0706.0542. Bibcode:2007AJ....133.2524W. doi:10.1086/514336. S2CID 122854.
- ↑ Barbieri, M.; Gratton, R. G. (March 2002). "Galactic orbits of stars with planets". Astronomy and Astrophysics. 384 (3): 879–883. arXiv:astro-ph/0112535. Bibcode:2002A&A...384..879B. doi:10.1051/0004-6361:20020011. S2CID 17066273.
- 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.
- 1 2 Mayor, M.; et al. (2004). "The CORALIE survey for southern extra-solar planets XII. Orbital solutions for 16 extra-solar planets discovered with CORALIE". Astronomy and Astrophysics. 415 (1): 391–402. arXiv:astro-ph/0310316. Bibcode:2004A&A...415..391M. doi:10.1051/0004-6361:20034250. S2CID 5233877.
- ↑ "HD 6434". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2014-09-08.
- 1 2 "Approved names". NameExoworlds. Retrieved 2020-01-02.
- ↑ "International Astronomical Union | IAU". www.iau.org. Archived from the original on 2022-12-05. Retrieved 2020-01-02.
- ↑ Fuhrmann, Klaus; Chini, Rolf (January 2019). "On ancient solar-type stars". Monthly Notices of the Royal Astronomical Society. 482 (1): 471–489. Bibcode:2019MNRAS.482..471F. doi:10.1093/mnras/sty2660.
- ↑ Fuhrmann, Klaus; Chini, Rolf (July 2026). "On ancient solar-type stars – III". Monthly Notices of the Royal Astronomical Society. 550 (2). Bibcode:2026MNRAS.550g1089F. doi:10.1093/mnras/stag1089. ISSN 0035-8711.
- ↑ "European Southern Observatory: Six Extrasolar Planets Discovered". SpaceRef Interactive Inc. 7 August 2000. Retrieved 15 August 2009. [permanent dead link]
