Astronomy:AR Cassiopeiae

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Short description: Star system in the constellation Cassiopeia

Coordinates: Sky map 23h 30m 0s, +58° 33′ 0″

AR Cassiopeiae
ARCasLightCurve.png
A light curve for AR Cassiopeiae, plotted from TESS data[1]
Observation data
{{#ifeq:J2000.0|J2000.0 (ICRS)|Epoch J2000.0      Equinox J2000.0 (ICRS)| [[History:Epoch|Epoch J2000.0]]      [[Astronomy:Equinox (celestial coordinates)|Equinox J2000.0}}
Constellation Cassiopeia[2]
AB
Right ascension  23h 30m 01.93946s[3]
Declination +58° 32′ 56.1120″[3]
Apparent magnitude (V) 4.883 (4.912 / 8.814)[4]
CD
Right ascension  23h 29m 52.2802s[5]
Declination +58° 32′ 54.458″[5]
Apparent magnitude (V) 7.09[6]
Characteristics
AB
Spectral type B4 V + A6 V[4]
U−B color index −0.62[7]
B−V color index −0.12[7]
Variable type Algol[8]
CD
Spectral type B9 V[6]
U−B color index −0.14[7]
B−V color index +0.01[7]
FG
Spectral type F7 IV + F9 V[9]
Astrometry
Radial velocity (Rv)−15.9±0.9[10] km/s
Proper motion (μ) RA: 17.90[3] mas/yr
Dec.: 4.15[3] mas/yr
Parallax (π)5.25 ± 0.52[3] mas
Distance620 ± 60 ly
(190 ± 20 pc)
Aa
Absolute magnitude (MV)−1.87±0.13[4]
Absolute bolometric
magnitude (Mbol)		−3.56±0.13[4]
Ab
Absolute magnitude (MV)2.20±0.11[4]
Absolute bolometric
magnitude (Mbol)		2.18±0.11[4]
Orbit[4]
PrimaryAa
CompanionAb
Period (P)6.0663170 d
Eccentricity (e)0.240
Inclination (i)85.34±0.50°
Periastron epoch (T)JD 2436847.9404±0.0055
Argument of periastron (ω)
(secondary)		41.82±0.47°
Details[4]
Aa
Mass5.90±0.20 M☉
Radius5.05±0.06 R☉
Surface gravity (log g)3.80±0.02 cgs
Temperature17,200±500 K
Ab
Mass1.86±0.06 M☉
Radius1.60±0.03 R☉
Surface gravity (log g)4.30±0.02 cgs
Temperature8,150±200 K
Other designations
AR Cassiopeiae (AB): 1H. Cas[11], AR Cas, BD+57°2748, HD 221253, HIP 115990, HR 8926, SAO 35478[8]
HD 221237 (CD): {{{names3}}}
FG: UCAC4 743-089692
Database references
SIMBADAR Cas (AB)
CD
D
F
G

AR Cassiopeiae (AR Cas) is a variable star in the constellation of Cassiopeia. It is thought to be a member of a septuple star system, one of only two known star systems with a multiplicity of 7, the other being Nu Scorpii.[12][9]

Nomenclature

The multiple star system as a whole has the designations ADS 16795, CCDM J23300+5833, and WDS J23300+5833AB in the Aitken Double Star Catalogue, the Catalogue of Components of Double and Multiple Stars, and the Washington Double Star Catalog respectively.[8]

AR Cassiopeiae has been referred to as IH Cas in some literature, looking similar to a variable star designation although not a valid one since the second letter of a variable star designation is always equal to the first or occurs later in the alphabet. The origin of the designation "IH Cassiopeiae" is from the 17th century catalogue and constellation map by Johannes Hevelius, which was kept in use due to the lack of a Flamsteed designation or Bayer designation for the star.[11] It was the first star in Cassiopeia that Flamsteed's edition of Hevelius catalogued,[13] thus "1 Hev. Cas" or "1 H. Cas" (similar to Gould designations), which becomes IH Cas through corruption.[11]

Properties

The primary star system, AR Cassiopeiae, is a triple. AR Cassiopeiae B is located 0.800″ away from AR Cassiopeiae A.[9] AR Cassiopeiae A itself is an Algol-type eclipsing binary with an orbital period of about 6.07 days.[4] Its primary is a B-type main-sequence star, and the secondary an A-type main-sequence star. The secondary star may be an Am star.[4]

Farther out are two other stars, designated components C and D. They are 76.1″, or about 1.27′, away from the central system.[9] Their combined spectrum matches that of another B-type main-sequence star.[6] This pair is also designated HD 221237.[6] 67.2″ (1.12′) away from AR Cassiopeiae is another pair of stars, F and G, both F-type stars.[9]

All these stars are known to be common proper motion companions.[9] However, the star listed as component E in most multiple star catalogues is an unrelated background star.

References

  1. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html. 
  2. ↑ WikiSky, "HD 221253" (accessed 2010-10-27)
  3. ↑ 3.0 3.1 3.2 3.3 3.4 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 Holmgren, D. E.; Hadrava, P.; Harmanec, P.; Eenens, P.; Corral, L. J.; Yang, S.; Ak, H.; Bozić, H. (1999). "Search for forced oscillations in binaries. III. Improved elements and the detection of line-profile variability of the B4V + A6V: system AR Cassiopeiae". Astronomy and Astrophysics 345: 855. Bibcode: 1999A&A...345..855H. 
  5. ↑ 5.0 5.1 Gaia Collaboration (2016). "Gaia Data Release 1". Astronomy & Astrophysics 595: A2. doi:10.1051/0004-6361/201629512. Bibcode: 2016A&A...595A...2G. 
  6. ↑ 6.0 6.1 6.2 6.3 "HD 221237". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+221237. 
  7. ↑ 7.0 7.1 7.2 7.3 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1. 
  8. ↑ 8.0 8.1 8.2 "V* AR Cas". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V%2A+AR+Cas. 
  9. ↑ 9.0 9.1 9.2 9.3 9.4 9.5 Tokovinin, A. A. (1997). "MSC - a catalogue of physical multiple stars". Astronomy and Astrophysics Supplement Series 124: 75–84. doi:10.1051/aas:1997181. Bibcode: 1997A&AS..124...75T. 
  10. ↑ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode: 1953GCRV..C......0W. 
  11. ↑ 11.0 11.1 11.2 Somerville, W. B. (1986). "1H. Cas = AR Cas". The Observatory 106: 40–42. Bibcode: 1986Obs...106...40S. 
  12. ↑ 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. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E. 
  13. ↑ John Flamsteed (1725). Historia coelestis Britannica, Volume 2. OCLC 311875456. https://books.google.com/books?id=jZhJtAEACAAJ. 



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