1 Persei

Star in the constellation Perseus

1 Persei
Observation data Epoch J2000.0 Equinox J2000.0
Location of 1 Persei (circled)
Constellation	Perseus
Right ascension	01^h 51^m 59.32008^s^[1]
Declination	+55° 08′ 50.5837″^[1]
Apparent magnitude (V)	5.49 - 5.74 - 5.85^[2]
Characteristics
Spectral type	B1.5V^[2]
Variable type	eclipsing binary^[3]
Astrometry

Proper motion (μ)	RA: 12.716(74)^[1] mas/yr Dec.: −8.410(79)^[1] mas/yr
Parallax (π)	2.6944 ± 0.0888 mas^[1]
Distance	1,210 ± 40 ly (370 ± 10 pc)
Absolute magnitude (M_V)	−1.37/−1.77^[4]

Orbit^[4]
Primary	1 Persei A
Companion	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^[4]
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^[3] 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.^[5] 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

A visual band light curve for V436 Persei, adapted from Janik *et al.* (2003)^[4]

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.^[6] In 1979 French amateur observers succeeded in determining an orbital period of 25.9 days.^[7] 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.^[2]

References

^ ^a ^b ^c ^d ^e 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.
^ ^a ^b ^c 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.
^ ^a ^b 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.
^ ^a ^b ^c ^d 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.

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