55 Arietis

55 Arietis

Observation data Epoch J2000      Equinox J2000
Constellation	Aries
Right ascension	03^h 09^m 36.74277^s[1]
Declination	+29° 04′ 37.4872″[1]
Apparent magnitude (V)	5.72[2]
Characteristics
Spectral type	B8 III[3]
U−B color index	–0.15[2]
B−V color index	+0.115±0.005[4]
Astrometry
Radial velocity (Rv)	−2.0±4.3[4] km/s
Proper motion (μ)	RA: +19.192[1] mas/yr Dec.: −12.057[1] mas/yr
Parallax (π)	3.5853 ± 0.1194 mas[1]
Distance	910 ± 30 ly (279 ± 9 pc)
Absolute magnitude (MV)	−1.75[4]
Details
Mass	4.1[5] M☉
Radius	9.49+0.32 −0.56[1] R☉
Luminosity	326±13[1] L☉
Surface gravity (log g)	2.948±0.023[5] cgs
Temperature	7,961+246 −128[1] K
Rotational velocity (v sin i)	196±10[5] km/s
Other designations
55 Ari, BD+28°499, FK5 1088, GC 3762, HD 19548, HIP 14677, HR 944, SAO 75757[6]
Database references
SIMBAD	data

55 Arietis is a single[7] star in the northern zodiac constellation of Aries. 55 Arietis is the Flamsteed designation. It is faintly visible to the naked eye as a dim, blue-white hued point of light with an apparent visual magnitude of 5.72.[2] Based upon an annual parallax shift of 3.6 mas,[1] it is approximately 910 light-years (280 parsecs) distant from Earth, give or take a 30 light-year margin of error. Eggen (1995) listed it as a proper motion candidate for membership in the IC 2391 supercluster.[8] It may be a runaway star, having a peculiar velocity of 25.9+3.9
−6.1 km/s relative to its neighbors.[9]

The spectrum of this star matches a B-type giant with a stellar classification of B8 III.[3] It has a high rate of spin, showing a projected rotational velocity of 196 km/s.[5] The star has 4.1[5] times the mass of the Sun but 9.5[1] times the Sun's radius. It is radiating 326[1] times as much luminosity as the Sun from its photosphere at an effective temperature of 7,961 K.[1]

References

1. 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. Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N.
3. 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.
4. 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.
5. Huang, W.; et al. (2010), "A Stellar Rotation Census of B Stars: From ZAMS to TAMS", The Astrophysical Journal, 722 (1): 605–619, arXiv:1008.1761, Bibcode:2010ApJ...722..605H, doi:10.1088/0004-637X/722/1/605, S2CID 118532653.
6. "55 Ari". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-07-31.
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. Eggen, Olin J. (December 1995), "Reality Tests of Superclusters in the Young Disk Population", Astronomical Journal, 110: 2862, Bibcode:1995AJ....110.2862E, doi:10.1086/117734.
9. Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.

External links

• HR 944
• Image 55 Arietis