Rho1 Cephei

From the Science Archives, the open-project database of science information that barely anyone can edit
Jump to navigation Jump to search
Rho1 Cephei
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cepheus
Right ascension 22h 26m 42.40624s[1]
Declination +78° 47′ 09.0725″[1]
Apparent magnitude (V) 5.84[2]
Spectral type A2m[3]
B−V color index −0.16[2]
Proper motion (μ) RA: −13.33[1] mas/yr
Dec.: −36.95[1] mas/yr
Parallax (π)15.83 ± 0.23[1] mas
Distance206 ± 3 ly
(63.2 ± 0.9 pc)
ρ1 Cep A
Mass2.00[3] M
Rotational velocity (v sin i)81[4] km/s
Age320[3] Myr
ρ1 Cep B
Mass0.51[3] M
Other designations
ρ1 Cep, 28 Cep, BD+78° 796, HD 213403, HIP 110787, HR 8578, SAO 10375, WDS J22267+7847AB[5]
Database references

Rho1 Cephei1 Cephei) is a double star located in the northern constellation of Cepheus. As of 2014, the pair had an angular separation of 0.29 arc seconds along a position angle of 211.1°. This corresponds to a projected separation of 18.1 AU.[3] Rho1 Cephei is faintly visible to the naked eye with an apparent visual magnitude of 5.84,[2] and it forms an optical pair with the brighter star Rho2 Cephei. Based upon an annual parallax shift of 15.83 mas as seen from the Earth,[1] Rho1 Cephei is located about 206 light years from the Sun.

The primary component is a chemically peculiar Am star with a stellar classification of A2m.[3] It has twice the mass of the Sun and is around 320 million years old.[3] The smaller companion may be the source of the X-ray emission from this location, as stars similar to the primary component do not generally produce detectable levels of X-rays.[6]


  1. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752, Bibcode 2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. 2.0 2.1 2.2 Oja, T. (August 1991), "UBV photometry of stars whose positions are accurately known. VI", Astronomy and Astrophysics Supplement Series 89 (2): 415–419, Bibcode 1991A&AS...89..415O.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 De Rosa, R. J. et al. (2013), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society 437 (2): 1216, arXiv:1311.7141, Bibcode 2014MNRAS.437.1216D, doi:10.1093/mnras/stt1932.
  4. Royer, F. et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics 393: 897–911, arXiv:astro-ph/0205255, Bibcode 2002A&A...393..897R, doi:10.1051/0004-6361:20020943.
  5. Lua error in Module:Citation/CS1 at line 379: attempt to call method 'match' (a nil value).
  6. De Rosa, R. J. et al. (July 2011), "The Volume-limited A-Star (VAST) survey - I. Companions and the unexpected X-ray detection of B6-A7 stars", Monthly Notices of the Royal Astronomical Society 415 (1): 854–866, arXiv:1103.4363, Bibcode 2011MNRAS.415..854D, doi:10.1111/j.1365-2966.2011.18765.x.