| absmag_v =
}}{{Starbox detail
| source =
| component1 = ρ1 Cep A
| mass = 2.00[4]
| radius =
| luminosity =
| temperature =
| gravity =
| metal_fe =
| rotational_velocity = 81[10]
| age_myr = 320[4]
| component2 = ρ1 Cep B
| mass2 = 0.51[4]
}}{{Starbox catalog
| names = ρ1 Cep, 28 Cep, BD+78° 796, HD 213403, HIP 110787, HR 8578, SAO 10375, WDS J22267+7847AB[13]
}}{{Starbox reference
| Simbad = rho01+Cep
}}{{Starbox end}}Rho1 Cephei (ρ1 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.[4] Rho1 Cephei is faintly visible to the naked eye with an apparent visual magnitude of 5.84,[3] 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,[ 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.[4] It has twice the mass of the Sun and is around 320 million years old.[4] 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.[19]
References
1. ^1 2 3 {{citation | title=UBV photometry of stars whose positions are accurately known. VI | last=Oja | first=T. | journal=Astronomy and Astrophysics Supplement Series | volume=89 | issue=2 | pages=415–419 | date=August 1991 | bibcode=1991A&AS...89..415O | postscript=. }}
2. ^1 {{citation | display-authors=1 | last1=De Rosa | first1=R. J. | last2=Bulger | first2=J. | last3=Patience | first3=J. | last4=Leland | first4=B. | last5=Macintosh | first5=B. | last6=Schneider | first6=A. | last7=Song | first7=I. | last8=Marois | first8=C. | last9=Graham | first9=J. R. | last10=Bessell | first10=M. | last11=Doyon | first11=R. | title=The Volume-limited A-Star (VAST) survey - I. Companions and the unexpected X-ray detection of B6-A7 stars | journal=Monthly Notices of the Royal Astronomical Society | volume=415 | issue=1 | pages=854–866 | date=July 2011 | doi=10.1111/j.1365-2966.2011.18765.x | bibcode=2011MNRAS.415..854D | postscript=. | arxiv=1103.4363 }}
3. ^1 2 3 4 5 6 7 {{citation | last1=De Rosa | first1=R. J. | last2=Patience | first2=J. | last3=Wilson | first3=P. A. | last4=Schneider | first4=A. | last5=Wiktorowicz | first5=S. J. | last6=Vigan | first6=A. | last7=Marois | first7=C. | last8=Song | first8=I. | last9=MacIntosh | first9=B. | last10=Graham | first10=J. R. | last11=Doyon | first11=R. | last12=Bessell | first12=M. S. | last13=Thomas | first13=S. | last14=Lai | first14=O. | title=The VAST Survey - III. The multiplicity of A-type stars within 75 pc | journal=Monthly Notices of the Royal Astronomical Society | volume=437 | issue=2 | pages=1216 | year=2013 | display-authors=1 | bibcode=2014MNRAS.437.1216D | doi=10.1093/mnras/stt1932 | arxiv=1311.7141 | postscript=. }}
4. ^1 {{citation | display-authors=1 | last1=Royer | first1=F. | last2=Grenier | first2=S. | last3=Baylac | first3=M.-O. | last4=Gómez | first4=A. E. | last5=Zorec | first5=J. | title=Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i | journal=Astronomy and Astrophysics | volume=393 | pages=897–911 | date=October 2002 | doi=10.1051/0004-6361:20020943 | bibcode=2002A&A...393..897R | arxiv=astro-ph/0205255 | postscript=. }}
5. ^1 {{cite simbad | title=rho01 Cep | accessdate=2017-05-05 | postscript=. }}