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AR Cassiopeiae

A light curve for AR Cassiopeiae, plotted from TESS data
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Cassiopeia
AB
Right ascension	23 30 01.93946
Declination	+58° 32′ 56.1120″
Apparent magnitude (V)	4.883 (4.912 / 8.814)
CD
Right ascension	23 29 52.2802
Declination	+58° 32′ 54.458″
Apparent magnitude (V)	7.09
Characteristics
AB
Spectral type	B4 V + A6 V
U−B color index	−0.62
B−V color index	−0.12
Variable type	Algol
CD
Spectral type	B9 V
U−B color index	−0.14
B−V color index	+0.01
FG
Spectral type	F7 IV + F9 V
Astrometry
Radial velocity (Rv)	−15.9±0.9 km/s
Proper motion (μ)	RA: 17.90 mas/yr Dec.: 4.15 mas/yr
Parallax (π)	5.25 ± 0.52 mas
Distance	620 ± 60 ly (190 ± 20 pc)
Aa
Absolute magnitude (MV)	−1.87±0.13
Absolute bolometric magnitude (Mbol)	−3.56±0.13
Ab
Absolute magnitude (MV)	2.20±0.11
Absolute bolometric magnitude (Mbol)	2.18±0.11
Orbit
Primary	Aa
Companion	Ab
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
Aa
Mass	5.90±0.20 M☉
Radius	5.05±0.06 R☉
Surface gravity (log g)	3.80±0.02 cgs
Temperature	17,200±500 K
Ab
Mass	1.86±0.06 M☉
Radius	1.60±0.03 R☉
Surface gravity (log g)	4.30±0.02 cgs
Temperature	8,150±200 K
Other designations
ADS 16795, CCDM J23300+5833, WDS J23300+5833
AR Cassiopeiae (AB): 1H. Cas, AR Cas, BD+57°2748, HD 221253, HIP 115990, HR 8926, SAO 35478
HD 221237 (CD): BD+57°2747, HD 221237, SAO 35476
FG: UCAC4 743-089692
Database references
SIMBAD	AR 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.

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.

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. It was the first star in Cassiopeia that Flamsteed's edition of Hevelius catalogued, thus "1 Hev. Cas" or "1 H. Cas" (similar to Gould designations), which becomes IH Cas through corruption.

Properties

The primary star system, AR Cassiopeiae, is a triple. AR Cassiopeiae B is located 0.800″ away from AR Cassiopeiae A. AR Cassiopeiae A itself is an Algol-type eclipsing binary with an orbital period of about 6.07 days. 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.

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

All these stars are known to be common proper motion companions. 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. Retrieved 8 December 2021.
2. WikiSky, "HD 221253" (accessed 2010-10-27)
3. ^ van Leeuwen, F.; et al. (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. S2CID 18759600.
4. ^ 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. ^ Gaia Collaboration (2016). "Gaia Data Release 1". Astronomy & Astrophysics. 595: A2. arXiv:1609.04172. Bibcode:2016A&A...595A...2G. doi:10.1051/0004-6361/201629512. S2CID 1828208.
6. ^ "HD 221237". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 23 August 2017.
7. ^ Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
8. ^ "V* AR Cas". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 23 August 2017.
9. ^ Tokovinin, A. A. (1997). "MSC - a catalogue of physical multiple stars". Astronomy and Astrophysics Supplement Series. 124: 75–84. Bibcode:1997A&AS..124...75T. doi:10.1051/aas:1997181.
10. Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W.
11. ^ 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. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
13. John Flamsteed (1725). Historia coelestis Britannica, Volume 2. OCLC 311875456.

v t e Constellation of Cassiopeia
List of stars in Cassiopeia Cassiopeia in Chinese astronomy
Stars	Bayer α (Schedar) β (Caph) γ (Navi/Tsih) δ (Ruchbah) ε (Segin) ζ (Fulu) η (Achird) θ (Marfak) ι κ λ μ ν ξ ο π ρ σ τ υ υ (Castula) φ χ ψ ω Flamsteed 1 2 4 6 9 10 12 42 47 48 (A) 49 50 54 Variable R S TZ WZ YZ (21) AO AR PZ V373 V509 V547 V669 V705 V762 V863 V773 V987 V1022 V1405 HR 5 91 144 196 244 273 297 743 932 8832 8853 8881 HD 861 7924 7977 15558 17156 (Nushagak) 240210 240237 240429 240430 Other BD+60°2522 Gliese 49 IRAS 23304+6147 LS I +61 303 PSR J0205+6449 Tycho G 4U 0142+61 WR 2 WR 3
Exoplanets HD 7924 b HD 17156 b HD 219134 b c d e (h) f g HD 240210 b HD 240237 b
Star clusters Messier 52 Messier 103 NGC 103 NGC 110 NGC 129 NGC 133 NGC 136 NGC 146 NGC 189 NGC 225 NGC 358 NGC 366 NGC 381 NGC 433 NGC 436 NGC 457 NGC 559 NGC 637 NGC 654 NGC 659 NGC 663 NGC 1027 NGC 7789 NGC 7790 Trumpler 3
Nebulae	NGC 281 7635 Other 3C 58 Cassiopeia A Heart Nebula IC 289 IC 1805 KjPn 8 LBN 114.55+00.22 Sh 2-185 Westerhout 5
Galaxies	NGC 147 185 278 Other Andromeda VII 3C 20 3C 35 Dwingeloo 1 Dwingeloo 2 MB 3 IC 10 Maffei 1 Maffei 2 QSO B0153+744
Astronomical events SN 1181 SN 1572 (B)
Category

• Cassiopeia (constellation)
• Algol variables
• Multiple star systems
• Objects with variable star designations
• Durchmusterung objects
• Henry Draper Catalogue objects
• Bright Star Catalogue objects
• Hipparcos objects
• B-type main-sequence stars