V636 Scorpii

Spectroscopic binary star system in the constellation Scorpius

V636 Sco
Observation data Epoch J2000 Equinox J2000
A light curve for V636 Scorpii, plotted from TESS data^[1]
Constellation	Scorpius
Right ascension	17^h 22^m 46.47796^s^[2]
Declination	−45° 36′ 51.3868″^[2]
Apparent magnitude (V)	6.40 - 6.92^[3]
Characteristics
Cepheid
Spectral type	F7/8Ib/II-G5^[3]
Variable type	δ Cep^[3]

companion
Spectral type	B9.5V^[4]
Astrometry

Radial velocity (R_v)	9.09 ± 0.17^[5] km/s
Proper motion (μ)	RA: -3.05 ± 1.03^[2] mas/yr Dec.: -2.40 ± 0.38^[2] mas/yr
Parallax (π)	1.15 ± 0.76 mas^[2]
Distance	approx. 3,000 ly (approx. 900 pc)
Absolute magnitude (M_V)	-3.64^[4]

Orbit
Period (P)	1,318 days^[4]
Semi-major axis (a)	6.7^[4]
Eccentricity (e)	0.26^[6]
Details
Cepheid
Mass	5.6^[4] `M`_☉
Radius	~50^[7] `R`_☉
Luminosity	2,500^[4] `L`_☉
Metallicity	+0.07^[8]
companion
Mass	2.4 `M`_☉
Other designations
V636 Sco, HIP 85035, CD−45°11441, HD 156979, SAO 227880
Database references
SIMBAD	data

V636 Scorpii is a multiple star system in the constellation Scorpius, 3,000 light years away. The primary is a Classical Cepheid (δ Cephei) variable and its visual magnitude varies from 6.4 to 6.9.

V636 Scorpii is a spectroscopic binary, and the fainter companion is thought to itself consist of two stars. The primary is a luminous yellow star and a δ Cephei variable. The less massive companion orbits every 3.6 years and is apparently a B9.5 main sequence star, but the dynamics of the system suggest that it may actually be a pair of stars is a close orbit.^[9]

The Cepheid primary pulsates regularly with a period of 6.79671 days. It is a yellow-white supergiant or bright giant that is 5.6 times as massive as the Sun and 2,500 times as luminous.^[4]

References

^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
^ ^a ^b ^c ^d ^e 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.
^ ^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 ^c ^d ^e ^f ^g Evans, Nancy Remage; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.; Karovska, Margarita; Tingle, Evan (2013). "Binary Cepheids: Separations and Mass Ratios in 5M ⊙ Binaries". Astronomical Journal. 146 (4): 93, 10 pp. arXiv:1307.7123v1. Bibcode:2013AJ....146...93E. doi:10.1088/0004-6256/146/4/93. S2CID 34133110.
^ Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; Levato, H.; Morrell, N. I.; Torres, G.; Udry, S. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727–732. arXiv:astro-ph/0406573. Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213. S2CID 119387088.
^ Evans, Nancy Remage; Carpenter, Kenneth G.; Robinson, Richard; Kienzle, Francesco; Dekas, Anne E. (2005). "High-Mass Triple Systems: The Classical Cepheid Y Carinae". The Astronomical Journal. 130 (2): 789–793. arXiv:astro-ph/0504169. Bibcode:2005AJ....130..789E. doi:10.1086/430458. S2CID 119342828.
^ Moskalik, P.; Gorynya, N. A. (2005). "Mean Angular Diameters and Angular Diameter Amplitudes of Bright Cepheids". Acta Astronomica. 55: 247. arXiv:astro-ph/0507076. Bibcode:2005AcA....55..247M.
^ Marsakov, V. A.; Koval', V. V.; Kovtyukh, V. V.; Mishenina, T. V. (2013). "Properties of the population of classical Cepheids in the Galaxy". Astronomy Letters. 39 (12): 851. Bibcode:2013AstL...39..851M. doi:10.1134/S1063773713120050. S2CID 119788977.
^ Böhm-Vitense, E.; Evans, N. R.; Carpenter, K.; Albrow, Michael D.; Cottrell, P. L.; Robinson, R.; Beck-Winchatz, B. (1998). "The Mass of the Cepheid Binary V636 Scorpii". The Astrophysical Journal. 505 (2): 903. Bibcode:1998ApJ...505..903B. doi:10.1086/306177. S2CID 122385825.

Constellation of Scorpius

Stars

Bayer	α (Antares) β (Acrab) δ (Dschubba) ε (Larawag) ζ¹ ζ² η θ (Sargas) ι¹ ι² κ (Girtab) λ (Shaula) μ¹ (Xamidimura) μ² (Pipirima) ν (Jabbah) ξ ο π (Fang) ρ (Iklil) σ (Alniyat) τ (Paikauhale) υ (Lesath) χ ψ ω¹ ω² G (Fuyue) H (β Nor) N (α Nor) Q
Flamsteed	1 (b) 2 (A) 3 4 11 12 (c¹) 13 (c²) 16 18 22 (i) 25 27
Variable	T U RR RS RV RY RZ AH AI AK AR BM CL FQ HK KQ V393 V453 V455 V482 V500 V636 V701 V703 V718 V728 V745 V760 V856 V861 V866 V884 V893 V900 V905 V906 V907 V911 V913 V915 V918 V919 V921 V922 V923 V929 V933 V949 V951 V952 V957 V965 V970 V973 V975 V992 V1003 V1007 V1018 V1026 V1033 V1034 V1036 V1040 V1051 V1058 V1068 V1073 (k) V1074 V1075 V1077 V1094 V1104 V1186 V1187 V1280 V1292 V1294 V1309
HR	5906 5910 5934 5965 5969 5973 5996 5998 5999 6000 6001 6003 6006 6007 6012 6015 6017 6044 6051 6053 6054 6061 6070 (d) 6076 6077 6078 6080 6094 6097 6100 6106 6122 6145 6160 6178 6192 6206 6209 6210 6211 6214 6218 6221 6244 6260 6266 6272 6273 6282 6298 6311 6316 6331 6338 6344 6366 6371 6381 6382 6389 6398 6403 6405 6409 6420 6454 6456 6460 6470 6501 6503 6517 6523 6539 6557 6558 6583 6587 6597 6613 6628 6643 6648 6649 6651 6653 6657 6658 6668 6671 6675 6678 6682 6683
HD	143567 144432 145377 146436 150248 150420 152424 153234 153950 (Rapeto) 155448 155985 158042 159868 162020
Other	Gliese 618 Gliese 667 Gliese 682 CD -35 11760 CD -38 10980 EPIC 204278916 EPIC 204376071 GCRT J1745−3009 GSC 06214-00210 GX 340+0 GX 349+2 H1-36 H1743-322 HIP 79431 (Sharjah) IGR J17091-3624 IGR J17252−3616 IRAS 17163−3907 K2-24 K2-33 LSS 4067 MOA-2008-BLG-310L MXB 1735-44 OAO 1657-415 OGLE-2005-BLG-071L OGLE-2005-BLG-390L OGLE-2006-BLG-109L Oph 162225-240515 Pismis 24-1 PSR B1620−26 PSR B1706−44 PSR B1737−30 PSR J1614−2230 Rapid Burster ROXs 12 1RXS J160929.1−210524 1RXS J170849.0−400910 Scorpius X-1 Th 28 Trumpler 27-1 Trumpler 27-27 Trumpler 27-28 Trumpler 27-102 Trumpler 27-105 4U 1700-37 4U 1702-42 4U 1705-44 4U 1724-307 4U 1728-34 4U 1746-371 UScoCTIO 108 VVV-WIT-07 WASP-17 (Dìwö) WR 86 WR 93b Wray 17-96 XTE J1720−318 XTE J1739−302 XTE J1751−305

Exoplanets	HD 145377 b HD 153950 b HD 159868 b HIP 78530 b HIP 79431 b K2-24b c K2-33b OGLE-2005-BLG-071Lb OGLE-2005-BLG-390Lb OGLE-2007-BLG-368Lb PSR B1620−26 b (Methuselah) WASP-17b V921 Scorpii b