HD 1

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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]
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
AG+67°4, BD+67°1599, HD  1, HIP  422, SAO  10963, GSC  04294-00080 [10]
Database references
SIMBAD data

HD 1, also known as HIP 422, is the first star catalogued in the Henry Draper Catalogue. It is located in the northern circumpolar constellation Cepheus 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 away 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. The components take approximately 6 years to circle each other in an eccentric orbit. [6] The visible component is an evolved red giant branch [1] (RGB) star with a stellar classification of G9-K0 IIIa, [3] a spectral class 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 1A is metal enriched, with an iron abundance 74% above solar levels. [8] The objects spins modestly with a projected rotational velocity of 5.6  km/s . [3]

Related Research Articles

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HD 27245, also known as HR 1335 or rarely 25 H. Camelopardalis is a solitary red-hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.4, making it faintly visible to the naked eye. Gaia DR3 Parallax measurements place it approximately 607 light years away from it the Solar System and is drifting further away with a heliocentric radial velocity of 25.2 km/s. At its current distance, HD 27245's brightness is diminished by 0.36 magnitudes due to extinction from interstellar dust. It has an absolute magnitude of −0.27.

HD 190984, also known as HIP 99496, is a star located in the southern circumpolar constellation Pavo, the peacock. It has an apparent magnitude of 8.76, making it readily visible in small telescopes, but not to the naked eye. Based on parallax measurements from the Gaia spacecraft, the object is estimated to be 486 light years away from the Solar System. It appears to be receding with a heliocentric radial velocity of 20.3 km/s.

HD 83332 is a solitary, orange hued star located in the southern constellation Antlia. It has an apparent magnitude of 5.68, making it faintly visible to the naked eye if viewed under ideal conditions. The star is located 285 light years away based on its annual parallax shift, but is drifting away with a radial velocity of 30 km/s.

HD 63399 is an orange hued star located in the southern constellation Puppis, the poop deck. It has an apparent magnitude of 6.45, placing it near the limit for naked eye visibility. Based on parallax measurements from Gaia DR3, the object is estimated to be 445 light years distant. It appears to be receding with a spectroscopic radial velocity of 28.5 km/s. At its current distance, HD 63399 is diminished by 0.29 magnitudes due to interstellar dust.

HD 126209, also known as HR 5389, is a solitary, orange hued star located in the southern circumpolar constellation Apus. It has an apparent magnitude of 6.06, making it faintly visible to the naked eye under ideal conditions. Based on parallax measurements from the Gaia spacecraft, the object is estimated to be 560 light years distant. It appears to be approaching the Solar System with a fairly constrained heliocentric radial velocity of −8.1 km/s. De Mederios et al. (2014) found the radial velocity to be variable, making it a probable spectroscopic binary. Eggen (1993) lists it as a member of the old disk population.

HD 39901 is an orange hued star located in the constellation Columba. It is also called HR 2069, which is the star's Bright Star Catalog designation. Eggen (1989) lists it as a member of the old disk population.

HD 30080, also known as HR 1509, is a solitary, orange hued star located in the southern constellation Caelum, the chisel. It has an apparent magnitude of 5.66, allowing it to be faintly visible to the naked eye. Parallax measurements from Gaia DR3 place the object at a distance of 612 light years. It appears to be approaching the Solar System with a heliocentric radial velocity of −3.8 km/s. Eggen (1989) lists it as a member of the thick disk population.

HD 75116, also known as HR 3491, is a solitary, orange hued star in the southern circumpolar constellation Volans, the flying fish. It has an apparent magnitude of 6.31, placing it near the limit for naked eye visibility. Parallax measurements from the Gaia spacecraft place the star relatively far at a distance of 930 light years. It appears to be approaching the Solar System, having a heliocentric radial velocity of −17.5 km/s.

<span class="mw-page-title-main">HD 27022</span> Star in the constellation Camelopardalis

HD 27022, also known as HR 1327, is a star located in the northern circumpolar constellation Camelopardalis. The object has also been designated as 20 H. Camelopardalis, but is not commonly used in modern times. It has an apparent magnitude of 5.27, allowing it to be faintly visible to the naked eye. Based on parallax measurements from Gaia DR3, the star has been estimated to be 347 light years away. It appears to be approaching the Solar System, having a heliocentric radial velocity of −19.5 km/s.

HD 193721 is an astrometric binary in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.77, allowing it to be faintly seen with the naked eye. Parallax measurements place the system 760 light years away from the Solar System and it is currently receding with a heliocentric radial velocity 8.6 km/s.

HD 193373 is a solitary red hued star located in the equatorial constellation Delphinus. It has an apparent magnitude of 6.21, placing it near the limit for naked eye visibility. Parallax measurements place it 846 light years distant and it is currently receding with a heliocentric radial velocity of 22.7 km/s.

HD 182509, also designated as HR 7370, is an orange hued star located in the southern constellation Telescopium. It has an apparent magnitude of 5.69, making it faintly visible to the naked eye if viewed under ideal conditions. Parallax measurements place the object at a distance of 635 light years. It has a poorly constrained heliocentric radial velocity of −5 km/s, indicating that it is drifting towards the Solar System.

HD 33519, also known as HR 1682, is a probable spectroscopic binary located in the southern circumpolar constellation Mensa. It is one of the stars near the limit of naked eye visibility, having an apparent magnitude of 6.28. The system is relatively far at a distance of 940 light years but is approaching with a heliocentric radial velocity of −2.5 km/s. However, this value is poorly constrained.

HD 37289, also known as HR 1916, is a solitary, orange hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.61, making it faintly visible to the naked eye under ideal conditions. Based on parallax measurements from the Gaia spacecraft, the object is estimated to be 308 light years distant. It appears to be approaching the Sun, having a heliocentric radial velocity of −20.7 km/s.

HD 30669 is a yellowish-orange hued star located in the southern constellation Caelum, the chisel. It has an apparent magnitude of 9.11, making it readily visible in small telescopes but not to the naked eye. The object is relatively close at a distance of 188 light years, based on parallax measurements from Gaia DR3. Its distance from the Solar System is rapidly increasing, having a heliocentric radial velocity of 66 km/s.

<span class="mw-page-title-main">HD 106248</span> Star in the constellation Chamaeleon

HD 106248, also known as HR 4649, is a solitary, orange hued star located in the southern circumpolar constellation Chamaeleon. It has an apparent magnitude of 6.34, placing it near the limit for naked eye visibility. Based on parallax measurements from Gaia DR3, the object is estimated to be 358 light years away from the Solar System. It appears to be receding with a heliocentric radial velocity of 34.5 km/s. At its current distance, HD 106248's brightness is diminished by 0.32 due to interstellar dust and Eggen (1993) lists it as a member of the old (thick) disk population.

<span class="mw-page-title-main">HD 187420/187421</span> Binary star in the constellation Telescopium

HD 187420 and HD 187421, are the components of a binary star located in the southern constellation Telescopium. Gaia DR3 parallax measurements place the stars at a distance of 407 and 414 light years respectively. The two are separated by 23″, and they are approaching the Solar System with heliocentric radial velocities of −17.9 km/s and −21.5 km/s respectively.

<span class="mw-page-title-main">HD 167096</span> Binary star; Corona Australis

HD 167096, also known as HR 6818 or rarely 4 G. Coronae Australis, is a binary star located in the southern constellation Corona Australis. It has an apparent magnitude of 5.45, making it faintly visible to the naked eye. The system is located relatively close at a distance of 224 light years based on Gaia DR3 parallax measurements but is drifting closer with a poorly constrained heliocentric radial velocity of −27 km/s. At its current distance HD 167096's brightness is diminished by three tenths of a magnitudes due to interstellar dust and it has an absolute magnitude of +0.64.

<span class="mw-page-title-main">HD 186756</span> K-type giant; Telescopium

HD 186756, also known as HR 7521 or rarely 68 G. Telescopii, is a solitary orange hued star located in the southern constellation Telescopium. It has an apparent magnitude of 6.25, placing it near the limit for naked eye visibility, even under ideal conditions. Gaia DR3 parallax measurements imply a distance of 743 light years; it is currently approaching with a heliocentric radial velocity of −21.2 km/s. At its current distance, HD 186756's brightness is diminished by 0.34 magnitudes due to extinction from interstellar dust and it has an absolute magnitude of −0.96.

<span class="mw-page-title-main">HD 120565</span> Spectroscopic binary in the constellation Camelopardalis

HD 120565, also designated as HR 5203, is a star located in the northern circumpolar constellation Camelopardalis. It is faintly visible to the naked eye as an orange-hued point of light with an apparent magnitude of 5.91. Gaia DR3 parallax measurements imply a distance of 370 light-years and it is currently drifting closer with a heliocentric radial velocity of −45.2 km/s. At its current distance, HD 120565's brightness is diminished by 0.12 magnitudes due to interstellar extinction and it has an absolute magnitude of +0.48.

References

  1. 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.
  2. 1 2 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.
  3. 1 2 3 4 5 6 7 8 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.
  4. 1 2 3 4 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.
  5. ↑ 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.
  6. 1 2 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.
  7. 1 2 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.
  8. 1 2 3 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.
  9. 1 2 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.
  10. ↑ "HD 1". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 23 September 2022.
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