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]
 | |
| 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] |
| Distance | 317 ± 3 ly (97.1 ± 0.9 pc) |
| Absolute magnitude (MV) | 0.52[2] |
| Details | |
| Mass | 2.25?[5] M☉ |
| Radius | 3.98+0.11 −0.13[1] R☉ |
| Luminosity | 44.3±0.5[1] L☉ |
| Temperature | 7466+217 −105[1] K |
| Rotational velocity (v sin i) | 110[4] km/s |
| Age | ~900[5] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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
edit- ^ a b c d e f g h i j k l 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.
- ^ a b c d e f 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.
- ^ a b 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.
- ^ a b c d 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.
- ^ a b c Jim Kaler. "HR 306 and HR 8938". Stars.astro.illinois.edu. Retrieved 2012-02-29.
- ^ "HD 221525". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-21.
- ^ 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.
- ^ Calculation:
![{\displaystyle ({\sqrt[{5}]{100}})^{5.56-1.97}\approx 27.2}](https://wikimedia.org/api/rest_v1/media/math/render/svg/f795715ca3e37975405bd60f2cd736b0e6694457)
External links
edit- Jim Kaler. "The Polar Project". University of Illinois. Retrieved 2012-05-02.
- HD 221525 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images