HD 1
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Cepheus |
Right ascension | 00h 05m 08.84054s[1] |
Declination | +67° 50′ 23.9805″[1] |
Apparent magnitude (V) | 7.42±0.01[2] |
Characteristics | |
Evolutionary stage | red giant branch[1][3] |
Spectral type | G9-K0 IIIa[3] |
Astrometry | |
Radial velocity (Rv) | −27.3±0.5[4] km/s |
Proper motion (μ) | RA: +7.480 mas/yr[1] Dec.: −5.045 mas/yr[1] |
Parallax (π) | 2.668 ± 0.0485 mas[1] |
Distance | 1,220 ± 20 ly (375 ± 7 pc) |
Absolute magnitude (MV) | −0.01[5] |
Orbit[6] | |
Primary | A |
Companion | B |
Period (P) | 6.345±0.007 yr |
Eccentricity (e) | 0.488±0.013 |
Periastron epoch (T) | 2,452,213±9 JD |
Argument of periastron (ω) (secondary) | 224±2.2° |
Semi-amplitude (K1) (primary) | 4.35±0.08 km/s |
Details | |
Mass | 3.0[3] M☉ |
Radius | 30[7] R☉ |
Luminosity | 226±5[4] L☉ |
Surface gravity (log g) | 1.81[8] cgs |
Temperature | 5,844±122[9] K |
Metallicity [Fe/H] | +0.24[8] dex |
Rotational velocity (v sin i) | 5.6±1.2[3] km/s |
Age | 350[3] Myr |
Other designations | |
Database references | |
SIMBAD | data |
HD 1, also known as HIP 422, is the first star catalogued in the HD. It is located in the northern circumpolar constellation Cephus and has an apparent magnitude of 7.42,[2] making it readily visible in binoculars, but not to the naked eye. The object is located relatively far at a distance of 1,220 light years but is approaching the Solar System with a spectroscopic radial velocity of −27.3 km/s.[4]
Characteristics
Originally thought to be a single object, observations from Griffin & McClure (2009) reveal it to be a single-lined spectroscopic binary. Both components take approximately 6 years to circle each other in an eccentric orbit.[6] The visible component is an evolved RGB[1] star with a stellar classification of G9-K0 IIIa,[3] a object intermediate between a G9 and K0 giant star. It has 3 times the mass of the Sun but at the age of 350 million years,[3] it has expanded to 30 times its girth.[7] It radiates 226 times the luminosity of the Sun[4] from its enlarged photosphere at an effective temperature of 5,844 K,[9] giving it a yellowish-orange hue. HD 1 A is metal enriched, with an iron abundance 73.8% above solar levels.[8] The objects spins modestly with a projected rotational velocity of 5.6 km/s.[3]
References
- ^ a b c d e f 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.
- ^ a b Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
- ^ a b c d e f g h Strassmeier, K.G.; Weber, M.; Granzer, T.; Dall, T.H. (20 April 2010). "HD 1: The number-one star in the sky". Astronomische Nachrichten. 331 (4): 368–377. Bibcode:2010AN....331..368S. doi:10.1002/asna.201011356. eISSN 1521-3994. ISSN 0004-6337.
- ^ a b c d 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.
- ^ Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. eISSN 1562-6873. ISSN 1063-7737. S2CID 119257644.
- ^ a b Griffin, R. F.; McClure, R. D. (February 2009). "Spectroscopic binary orbits for the Henry Draper Catalogue stars". The Observatory. 129: 28–32. Bibcode:2009Obs...129...28G. ISSN 0029-7704.
- ^ a b Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv:2109.10912. Bibcode:2022A&A...657A...7K. doi:10.1051/0004-6361/202142146. eISSN 1432-0746. ISSN 0004-6361.
- ^ a b c Anders, F.; et al. (August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy & Astrophysics. 628: A94. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. eISSN 1432-0746. ISSN 0004-6361.
- ^ a b Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. eISSN 1538-3881.
- ^ "HD 1". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 23 September 2022.