B Persei

Star in the constellation Perseus

b Persei
Observation data Epoch J2000.0 Equinox J2000.0
Location of b Persei (circled)
Constellation	Perseus
Right ascension	04^h 18^m 14.61690^s^[1]
Declination	+50° 17′ 43.8058″^[1]
Apparent magnitude (V)	4.52 - 4.68^[2]
Characteristics
Spectral type	A1III^[3]
B−V color index	+0.04^[4]
Variable type	Ellipsoidal^[2]
Astrometry

Radial velocity (R_v)	19.8±0.9^[5] km/s
Proper motion (μ)	RA: 45.42±0.40^[1] mas/yr Dec.: −56.72±0.32^[1] mas/yr
Parallax (π)	10.40 ± 0.35 mas^[1]
Distance	310 ± 10 ly (96 ± 3 pc)
Absolute magnitude (M_V)	0.3^[6]

Orbit^[7]
Primary	A or Aa
Companion	C or Ac
Period (P)	701.76 days
Semi-major axis (a)	5.09 mas
Eccentricity (e)	0.235
Inclination (i)	83.46°
Longitude of the node (Ω)	115.29°
Periastron epoch (T)	2440143.3984
Argument of periastron (ω) (secondary)	263°
Details
A or Aa
Mass	2.25^[6] `M`_☉
Radius	3.2^[8] `R`_☉
Luminosity	10^[9] `L`_☉
Temperature	9000^[6] K
Rotational velocity (v sin i)	81^[10] km/s


B or Ab
Mass	0.56^[11] `M`_☉
Radius	0.25^[8] `R`_☉
C or Ac
Mass	1.24^[11] `M`_☉
Luminosity	2^[9] `L`_☉
Other designations
BD+49°1150, GC 5174, HD 26961, HR 1324, HIP 20070, SAO 24531
Database references
SIMBAD	data

Light curves for b Persei. The top panel, plotted from *TESS* data,^[12] shows the variability of the inner binary pair. The lower panels, plotted from AAVSO data,^[13] show two eclipses.

b Persei (also known as HD 26961) is a spectroscopic triple star in the constellation Perseus. Its apparent magnitude is 4.60,^[6] and it is about 320 light years away.^[1]

In addition to the primary, an A-type giant, there is a smaller and cooler companion in a 1.53 day orbit, probably an F-class star around absolute magnitude 3.0, and a more distant companion (star C or Ac) in an orbit calculated to be 702 days long.^[6] The close binary pair forms a rotating ellipsoidal variable with a 1.53 day period. Star C forms an Algol-type variable system with the close binary, showing both primary eclipses (when star C passes in front of the inner pair) and secondary eclipses (when the inner pair passes in front of star C).^[14] Timings of the eclipses show a 705.4-day period.^[9]

References

^ ^a ^b ^c ^d ^e ^f 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. S2CID 18759600. Vizier catalog entry
^ ^a ^b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
^ Abt, Helmut A. (2009). "MK Classifications of Spectroscopic Binaries". The Astrophysical Journal Supplement. 180 (1): 117–18. Bibcode:2009ApJS..180..117A. doi:10.1088/0067-0049/180/1/117. S2CID 122811461.
^ 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. Vizier catalog entry
^ Wilson, R. E. (1953). General Catalogue of Stellar Radial Velocities. Carnegie Institution for Science. Bibcode:1953GCRV..C......0W. LCCN 54001336.
^ ^a ^b ^c ^d ^e Hill, G.; Aikman, G. C. L.; Cowley, A. P.; Bolton, C. T.; Thomas, J. C. (1976). "The radio-flaring triple system B Per". The Astrophysical Journal. 208: 152. Bibcode:1976ApJ...208..152H. doi:10.1086/154590.
^ ESA (1997). "The Hipparcos and Tycho Catalogues". VizieR On-line Data Catalog. 1239. Bibcode:1997yCat.1239....0E.
^ ^a ^b Duerbeck, H. W.; Schettler, A. (1979). "Photometric and spectroscopic study of the ellipsoidal variable b Persei". Acta Astronomica. 29: 225. Bibcode:1979AcA....29..225D.
^ ^a ^b ^c "Alert Notice 791: Anticipated secondary eclipse of b Per centered on September 29 2022 UT". AAVSO. Retrieved 2022-09-15.
^ Royer, F. (2007). "Rotational velocities of A-type stars. III. Velocity distributions". Astronomy and Astrophysics. 463 (2): 671–682. arXiv:astro-ph/0610785. Bibcode:2007A&A...463..671R. doi:10.1051/0004-6361:20065224. S2CID 18475298.
^ ^a ^b Tokovinin, Andrei (23 February 2018). "The Updated Multiple Star Catalog". The Astrophysical Journal Supplement Series. 235 (1): 6. arXiv:1712.04750. Bibcode:2018ApJS..235....6T. doi:10.3847/1538-4365/aaa1a5. eISSN 1538-4365.
^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 14 September 2022.
^ "Download Data". aavso.org. AAVSO. Retrieved 14 September 2022.
^ "b Per". The International Variable Star Index. AAVSO. Retrieved 15 September 2022.

Constellation of Perseus

Stars

Bayer	α (Mirfak) β (Algol) γ δ ε ζ η (Miram) θ ι κ (Misam) λ μ ν ξ (Menkib) ο (Atik) π (Gorgonea Secunda) ρ (Gorgonea Tertia) σ τ φ ψ ω (Gorgonea Quarta) b
Flamsteed	1 2 3 4 (g) 5 7 8 9 (i) 10 11 12 14 16 17 20 21 24 29 30 31 32 (l) 34 36 40 (o) 42 (n) 43 (A) 48 (c) 49 50 52 (f) 53 (d) 54 55 56 57 (m) 58 (e) 59 1 Aur
Variable	S T U V X Z RS RT RV RW RY ST SU SV TZ UV UX UY VX XX XY XZ YZ AB AG AR AS AW AX BM DM DY FO GK IK IP IQ IU IW IX IZ KP KS KT KW LX V351 V356 V357 V361 V376 V380 V386 V392 V396 V400 V423 V432 V440 V459 V461 V471 V472 V473 V480 V490 V492 V505 V509 V518 V520 (61 And) V521 V545 V551 V572 V573 V575 V576 V621 V718 V1024
HR	470 526 529 538 540 621 641 787 792 810 820 831 842 846 849 864 865 876 885 886 890 894 918 (k) 920 923 930 949 950 956 964 966 969 973 975 979 986 991 1001 1019 1034 1037 1041 1047 1051 1056 1059 1074 1097 1113 1127 1130 1133 1141 1160 1164 1176 1191 1197 1198 1207 1215 1226 1234 1286 1301 1330 1333 1337 1344 1371 1390 1419 1424 1482 1489 1493 1500 1514
HD	13519 14433 14434 16691 16760 17092 17245 17605 21684 22781 23301 23596 25329 26702 29587
Other	BD+31 643 BD+48 740 G 38-29 G 95-57 GD 61 HAT-P-15 (Berehynia) HAT-P-29 (Muspelheim) IRAS 04296+3429 L1448-IRS2E LkHα 101 LRLL 54361 NGC 1333 13 NGC 1333 IRAS 2A NGC 1333 IRAS 4A NGC 1333 IRAS 4B NGC 1624-2 PSR B0355+54 PSR J0357+3205 WR 4

Exoplanets	WASP-11b/HAT-P-10b

Star
clusters

NGC	869 (h) 884 (χ) 957 1039 1220 1285 1342 1444 1513 1528 1545 1624
Other	Alpha Persei Cluster IC 348 Trumpler 2

Nebulae

NGC	650 (Little Dumbbell Nebula) 1333 1491 1499 (California Nebula) 1579
Other	Barnard 203 Wreath Nebula

Galaxies

NGC	1003 1023 1058 1077 1160 1161 1167 1169 1250 1259 1260 1264 1265 1267 1268 1270 1271 1272 1273 1274 1275 1277 1278 1279 1281 1282 1283 1293 1294 1334
Other	IC 310 UGC 2885 (Godzilla galaxy) 4C +37.11