48 Cassiopeiae

48 Cassiopeiae is a triple star[11][7] system in the northern constellation of Cassiopeia. It is visible to the naked eye with a combined apparent visual magnitude of 4.49.[2] With an annual parallax shift of 28.36±0.44 mas as seen from Earth's orbit, it is located approximately 115 light years away.[1] The system is moving closer with a heliocentric radial velocity of −12.4 km/s.[5]

48 Cassiopeiae
Observation data
Epoch J2000      Equinox J2000
Constellation Cassiopeia
Right ascension  02h 01m 57.45035s[1]
Declination +70° 54′ 25.2902″[1]
Apparent magnitude (V) 4.49[2]
Characteristics
Spectral type A3 Va[3] (A2 V + F2 V)[4]
B−V color index 0.164±0.008[2]
Astrometry
Radial velocity (Rv)−12.4[5] km/s
Proper motion (μ) RA: −55.69[1] mas/yr
Dec.: −8.71[1] mas/yr
Parallax (π)28.36 ± 0.44[1] mas
Distance115 ± 2 ly
(35.3 ± 0.5 pc)
Absolute magnitude (MV)1.75[2]
Orbit[6]
Primary48 Cas A
Companion48 Cas B
Period (P)61.14±0.05 yr
Semi-major axis (a)0.614±0.002″
Eccentricity (e)0.355±0.001
Inclination (i)16.7±0.9°
Longitude of the node (Ω)48.2±3.2°
Periastron epoch (T)1964.35±0.09
Argument of periastron (ω)
(secondary)		19.5±3.6°
Details
48 Cas A
Mass1.93[7] M☉
Luminosity17.8+0.6
−1.2[8] L☉
Surface gravity (log g)4.47[9] cgs
Temperature8,538±290[9] K
Metallicity [Fe/H]−0.4[5] dex
Rotational velocity (v sin i)61[8] km/s
Age376[9] Myr
48 Cas B
Mass1.17[7] M☉
Other designations
A Cassiopeiae, 48 Cas, BD+70° 153, HD 12111, HIP 9480, HR 575, SAO 4554, ADS 1598, CCDM J02020+7054, WDS J02020+7054AB[10]
Database references
SIMBADdata

The primary component, designated 48 Cassiopeiae A, is a white A-type main-sequence star with a stellar classification of A2 V[4] and an apparent magnitude of +4.65.[12] It has a companion, component B, which is an F-type main-sequence star of class F2 V[4] and an apparent magnitude of +6.74.[12] This pair orbit around their common centre of mass once every 61.1 years.[6] They have a semimajor axis of 0.614 arcseconds and an eccentricity of 0.355.[6] A third companion, component C, is a magnitude 13.20[12] star located at an angular separation of 23.16 arcseconds as of 2014, or at least 816.5 AU away.[7]

48 Cassiopeiae also has the Bayer designation A Cassiopeiae, the only star with a Latin letter designation in the constellation.[13]

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.
  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.
  3. Gray, R. O.; Garrison, R. F. (July 1989), "The Late A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation", Astrophysical Journal Supplement, 70: 623, Bibcode:1989ApJS...70..623G, doi:10.1086/191349.
  4. Edwards, T. W. (1976), "MK classification for visual binary components", The Astronomical Journal, 81: 245, Bibcode:1976AJ.....81..245E, doi:10.1086/111879.
  5. Gebran, M.; et al. (2016), "A new method for the inversion of atmospheric parameters of A/Am stars", Astronomy & Astrophysics, 589: A83, arXiv:1603.01146, Bibcode:2016A&A...589A..83G, doi:10.1051/0004-6361/201528052.
  6. Hartkopf, W. I.; et al. (June 30, 2006), Sixth Catalog of Orbits of Visual Binary Stars, United States Naval Observatory, retrieved 2018-06-25.
  7. De Rosa, R. J.; et al. (2014), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society, 437 (2): 1216, arXiv:1311.7141, Bibcode:2014MNRAS.437.1216D, doi:10.1093/mnras/stt1932.
  8. 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.
  9. David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146.
  10. "48 Cas". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-06-19.
  11. 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.
  12. Mason, B. D.; et al. (2014), The Washington Visual Double Star Catalog, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22.
  13. Kostjuk, N. D. (2004), "VizieR Online Data Catalog: HD-DM-GC-HR-HIP-Bayer-Flamsteed Cross Index (Kostjuk, 2002)", VizieR On-line Data Catalog: IV/27A. Originally Published in: Institute of Astronomy of Russian Academy of Sciences (2002), 4027, Bibcode:2004yCat.4027....0K.
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