HD 6434

HD 6434 is a star in the southern constellation of Phoenix. Yellow dwarfs such as this are not very luminous, so at a distance of 138^[2] 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]

HD 6434 / Nenque

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Phoenix[1]
Right ascension	01h 04m 40.15037s[2]
Declination	–39° 29′ 17.5856″[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)	+22.92±0.14[2] km/s
Proper motion (μ)	RA: −170.124±0.106[2] mas/yr Dec.: −527.851±0.078[2] mas/yr
Parallax (π)	23.5794 ± 0.0417 mas[2]
Distance	138.3 ± 0.2 ly (42.41 ± 0.08 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
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
ARICNS	data

The star HD 6434 is named Nenque. The name was selected in the NameExoWorlds campaign by Ecuador, during the 100th anniversary of the IAU. Nenque means the Sun in the language spoken by the Indigenous Waorani tribes.^[9][10]

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]

Planetary system

In 2000, a planet, designated HD 6434 b, was detected in a close orbit around the star. The peer-reviewed scientific paper was published four years later.^[12][7]

The HD 6434 planetary system^[3]

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

• 94 Ceti
• List of extrasolar planets

References

1. Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific. 99 (617): 695–699. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Vizier query form
2. 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.
3. 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.
4. 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.
5. 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.
6. 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.
7. 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.
8. "HD 6434". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2014-09-08.
9. "Approved names". NameExoworlds. Retrieved 2020-01-02.
10. "International Astronomical Union | IAU". www.iau.org. Retrieved 2020-01-02.
11. 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.
12. "European Southern Observatory: Six Extrasolar Planets Discovered". SpaceRef Interactive Inc. 7 August 2000. Retrieved 15 August 2009.

External links