PROFILBARU.COM

b Persei
	Location of b Persei (circled)
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Perseus
Right ascension	04h 18m 14.61690s
Declination	+50° 17′ 43.8058″
Apparent magnitude (V)	4.52 - 4.68
Characteristics
Spectral type	A1III
B−V color index	+0.04
Variable type	Ellipsoidal
Astrometry
Radial velocity (Rv)	19.8±0.9 km/s
Proper motion (μ)	RA: 45.42±0.40 mas/yr ; Dec.: −56.72±0.32 mas/yr
Parallax (π)	10.40 ± 0.35 mas
Distance	310 ± 10 ly ; (96 ± 3 pc)
Absolute magnitude (MV)	0.3
Orbit
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 M☉
Radius	3.2 R☉
Luminosity	10 L☉
Temperature	9000 K
Rotational velocity (v sin i)	81 km/s
B or Ab
Mass	0.56 M☉
Radius	0.25 R☉
C or Ac
Mass	1.24 M☉
Luminosity	2 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, making it visible to the naked eye.^[6] 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 Institute Washington D.C. Publication. 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.