HD 221525
Diagram showing star positions and boundaries of the Cepheus constellation and its surroundings
Location of HD 221525 (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cepheus
Right ascension 23h 27m 00.91338s[1]
Declination 87° 18′ 27.0304″[1]
Apparent magnitude (V) 5.56[2]
Characteristics
Spectral type A8III[3] or A7IV[4]
B−V color index 0.250±0.004[2]
Astrometry
Radial velocity (Rv)−10.9±2.9[2] km/s
Proper motion (μ) RA: +75.736[1] mas/yr
Dec.: +16.724[1] mas/yr
Parallax (π)10.3023 ± 0.0957 mas[1]
Distance317 ± 3 ly
(97.1 ± 0.9 pc)
Absolute magnitude (MV)0.52[2]
Details
Mass2.25?[5] M☉
Radius3.98+0.11
−0.13[1] R☉
Luminosity44.3±0.5[1] L☉
Temperature7466+217
−105[1] K
Rotational velocity (v sin i)110[4] km/s
Age~900[5] Myr
Other designations
BD+86°3444, HD 221525, HIP 115746, HR 8938, SAO 3916[6]
Database references
SIMBADdata

HD 221525 is a single[7] star near the north celestial pole[5] in the constellation Cepheus. At an apparent magnitude of 5.56,[2] it can be seen with the naked eye under dark skies. It is about 30 times fainter than the nearby prominent star Polaris.[8] Based upon parallax measurements, HD 221525 is located at a distance of approximately 317 light years from the Sun,[1] but is drifting closer with a radial velocity of −11 km/s.[2]

This object is an A-type star with a stellar classification of A7IV[4] or A8III,[3] suggesting it is an evolving star on the subgiant or giant branch, respectively. It has a relatively high rate of spin, showing a projected rotational velocity of 110 km/s.[4] The star has four[1] times the radius of the Sun and is radiating 44[1] times the Sun's luminosity from its photosphere at an effective temperature of 7,466 K.[1]

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 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.
  2. 1 2 3 4 5 6 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. 1 2 Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
  4. 1 2 3 4 Cowley, Anne; Fraquelli, Dorothy (1974). "MK Spectral Types for Some Bright F Stars". Publications of the Astronomical Society of the Pacific. 86 (509): 70. Bibcode:1974PASP...86...70C. doi:10.1086/129562.
  5. 1 2 3 Jim Kaler. "HR 306 and HR 8938". Stars.astro.illinois.edu. Retrieved 2012-02-29.
  6. ↑ "HD 221525". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-21.
  7. ↑ Eggleton, P. P.; Tokovinin, A. A. (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.
  8. ↑ Calculation:
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