1 Persei

1 Persei
	Location of 1 Persei (circled)
Observation data; Epoch J2000.0 Equinox ICRS
Constellation	Perseus
Right ascension	01h 51m 59.32008s
Declination	+55° 08′ 50.5837″
Apparent magnitude (V)	5.49 - 5.74 - 5.85
Characteristics
Spectral type	B1.5V
Variable type	eclipsing binary
Astrometry
Proper motion (μ)	RA: 12.716(74) mas/yr ; Dec.: −8.410(79) mas/yr
Parallax (π)	2.6944±0.0888 mas
Distance	1,210 ± 40 ly ; (370 ± 10 pc)
Absolute magnitude (MV)	−1.37/−1.77
Orbit
Primary	1 Persei A
Secondary	1 Persei B
Period (P)	25.935951±0.000003 d
Eccentricity (e)	0.3768±0.0014
Inclination (i)	88.048±0.002°
Periastron epoch (T)	2443563.466±0.005 HJD
Argument of periastron (ω); (secondary)	109.83±0.10°
Semi-amplitude (K1); (primary)	97.4±0.1 km/s
Semi-amplitude (K2); (secondary)	91.2±0.1 km/s
Details
Primary
Mass	6.95 M☉
Radius	3.29 R☉
Luminosity	2,188 L☉
Surface gravity (log g)	4.25 cgs
Temperature	21,500 K
Rotation	1.45 days
Rotational velocity (v sin i)	115 km/s
Secondary
Mass	7.42 M☉
Radius	3.86 R☉
Luminosity	3,311 L☉
Surface gravity (log g)	4.14 cgs
Temperature	22,000 K
Rotation	1.40 days
Rotational velocity (v sin i)	140 km/s
Other designations
	V436 Persei, BD+54 396, HD 11241, HIP 8704, HR 533, SAO 22690
Database references
SIMBAD	data

1 Persei (1 Per) is an eclipsing binary star in the constellation Perseus. Its uneclipsed apparent magnitude is 5.49. The binary star consists of two B2 type main-sequence stars in a 25.9 day eccentric orbit. The stars are surrounded by a faint cloud of gas visible in mid-infrared, although whether they are the origin of the gas or simply passing through it is unclear.

Observational history

The possible eclipsing binary nature of 1 Persei was first noticed by Donald Kurtz in 1977 when it was used as a comparison star to test for photometric variability of HD 11408. In 1979 French amateur observers succeeded in determining an orbital period of 25.9 days. During the primary eclipse, the brightness drops to magnitude 5.85. In the secondary eclipses, the brightness drops to magnitude 5.74. The eclipses each last for approximately 25 hours.

References

1 2 3 4 5 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
1 2 3 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.
1 2 North, P.; et al. (1981). "1 Per: a new eclipsing binary with a long period and an elliptical orbit" (PDF). Information Bulletin on Variable Stars. 2036: 1. Bibcode:1981IBVS.2036....1N.
1 2 3 4 Janík, J.; et al. (2003). "Search for forced oscillations in binaries. IV. The eclipsing binary V436 Per revisited". Astronomy and Astrophysics. 408 (2): 611–619. Bibcode:2003A&A...408..611J. doi:10.1051/0004-6361:20030960.
↑ Harmanec, P.; et al. (1997). "Search for forced oscillations in binaries. I. The eclipsing and spectroscopic binary V436 Persei = 1 Persei". Astronomy and Astrophysics. 319 (2): 867–880. Bibcode:1997A&A...319..867H.
↑ Kurtz, D. W. (1977). "The photometric variability of 1 Per". Publications of the Astronomical Society of the Pacific. 89: 939–940. Bibcode:1977PASP...89..939K. doi:10.1086/130251.
↑ Figer, Alain; Maurin, Luc (1979). "1 Persei, a low amplitude eclipsing binary, has a period of 25.939 days and an elliptical orbit". GEOS Circular on Eclipsing Binaries. 2 (EB 2). Bibcode:1979GEOCE...2.....F.

[Gaia_EDR3-1] 1 2 3 4 5 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.

[gcvs-2] 1 2 3 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.

[North1981-3] 1 2 North, P.; et al. (1981). "1 Per: a new eclipsing binary with a long period and an elliptical orbit" (PDF). Information Bulletin on Variable Stars. 2036: 1. Bibcode:1981IBVS.2036....1N.

[Janík2003-4] 1 2 3 4 Janík, J.; et al. (2003). "Search for forced oscillations in binaries. IV. The eclipsing binary V436 Per revisited". Astronomy and Astrophysics. 408 (2): 611–619. Bibcode:2003A&A...408..611J. doi:10.1051/0004-6361:20030960.

[Harmanec1997-5] Harmanec, P.; et al. (1997). "Search for forced oscillations in binaries. I. The eclipsing and spectroscopic binary V436 Persei = 1 Persei". Astronomy and Astrophysics. 319 (2): 867–880. Bibcode:1997A&A...319..867H.

[Kurtz1977-6] Kurtz, D. W. (1977). "The photometric variability of 1 Per". Publications of the Astronomical Society of the Pacific. 89: 939–940. Bibcode:1977PASP...89..939K. doi:10.1086/130251.

[Figer1979-7] Figer, Alain; Maurin, Luc (1979). "1 Persei, a low amplitude eclipsing binary, has a period of 25.939 days and an elliptical orbit". GEOS Circular on Eclipsing Binaries. 2 (EB 2). Bibcode:1979GEOCE...2.....F.