7 Camelopardalis

7 Camelopardalis is a multiple star system[9] in the northern circumpolar constellation of Camelopardalis. It is located approximately 370 light years from the Sun, as determined from its parallax.[1] This system is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 4.43.[2] It is moving closer to the Earth with a heliocentric radial velocity of −10 km/s.[5]

7 Camelopardalis
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Camelopardalis
Right ascension 04h 57m 17.19609s[1]
Declination +53° 45′ 07.5654″[1]
Apparent magnitude (V) 4.43[2] (4.49 + ? + 7.90 + 11.30)[3]
Characteristics
Evolutionary stage main sequence
Spectral type A1 V[4]
B−V color index −0.017±0.003[2]
Astrometry
Radial velocity (Rv)−9.5±3.7[5] km/s
Proper motion (μ) RA: −24.51[1] mas/yr
Dec.: +7.71[1] mas/yr
Parallax (π)8.77 ± 0.60[1] mas
Distance370 ± 30 ly
(114 ± 8 pc)
Absolute magnitude (MV)−0.84[2]
Orbit[6]
Primary7 Cam Aa
Companion7 Cam Ab
Period (P)3.884494 d
Eccentricity (e)(0.045)
Periastron epoch (T)2,418,686.714 JD
Argument of periastron (ω)
(secondary)		(265)°
Semi-amplitude (K1)
(primary)		35.8 km/s
Details
7 Cam Aa
Mass3.16±0.10[7] M☉
Luminosity221.6+36.8
−31.5[7] L☉
Temperature9,226+236
−231[7] K
Rotational velocity (v sin i)40[7] km/s
Other designations
7 Cam, BD+53°829, GC 6017, HD 31278, HIP 23040, HR 1568, SAO 24929, ADS 3536, WDS J04573+5345[8]
Database references
SIMBADdata

The primary member of the group, designated component A, is a single-lined spectroscopic binary system with an orbital period of 3.88 days and a negligible eccentricity.[6] The visible component of this pair is a magnitude 4.49[3] A-type main-sequence star with a stellar classification of A1 V.[4] It has 3.2 times the mass of the Sun and is spinning with a projected rotational velocity of 40 km/s. The star is radiating 222 times the Sun's luminosity from its photosphere at an effective temperature of 9,226 K.[7]

The magnitude 7.90[3] component B has an orbital solution with the Aa/Ab pair, which yields a period of 284 years and an eccentricity of 0.74. However, Drummond (2014) found the data to be discordant and instead determined that they are an optical pair with no physical association.[10] The fourth member, component C, is a magnitude 11.30 star at an angular separation of 25.50″ along a position angle of 242° from the primary, as of 2003.[3]

References
  1. 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, S2CID 18759600.
  2. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  3. Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
  4. Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
  5. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
  6. Lucy, L. B.; Sweeney, M. A. (August 1971), "Spectroscopic binaries with circular orbits", Astronomical Journal, 76: 544–556, Bibcode:1971AJ.....76..544L, doi:10.1086/111159.
  7. Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
  8. "7 Cam". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-04-15.
  9. Eggleton, P. P.; et al. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  10. Drummond, Jack D. (March 2014), "Binary Stars Observed with Adaptive Optics at the Starfire Optical Range", The Astronomical Journal, 147 (3): 10, Bibcode:2014AJ....147...65D, doi:10.1088/0004-6256/147/3/65, 65.
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