TW Andromedae

Star in the constellation Andromeda

TW Andromedae
Observation data Epoch J2000 Equinox J2000
The visual band light curve of TW Andromedae, plotted from data published by Ammann & Walter^[1]
Constellation	Andromeda
Right ascension	00^h 03^m 18.22724^s^[2]
Declination	+32° 50′ 45.10209″^[2]
Apparent magnitude (V)	8.98 – 11.050 variable ^[3]
Characteristics
Spectral type	F0V + K0 ^[3]
B−V color index	0.11^[4]
Variable type	EA^[3]
Astrometry

Radial velocity (R_v)	−51.27±0.42^[5] km/s
Proper motion (μ)	RA: 52.569 ± 0.053 ^[2] mas/yr Dec.: -2.770 ± 0.028 ^[2] mas/yr
Parallax (π)	3.1877 ± 0.0442 mas^[2]
Distance	1,020 ± 10 ly (314 ± 4 pc)

Orbit
Period (P)	4.12 ^[6] days
Semi-major axis (a)	13.6 `R`_☉ ^[6]
Eccentricity (e)	0.0 ^[7]
Inclination (i)	86.9 ^[6]°
Periastron epoch (T)	JD 2440700±300^[7]
Semi-amplitude (K₁) (primary)	27±1.5^[7] km/s
Semi-amplitude (K₂) (secondary)	140±2.0^[7] km/s
Details
TW And A
Mass	1.685^[8] `M`_☉
Radius	2.05^[6] `R`_☉
Luminosity	4.3^[8] `L`_☉
Temperature	7250±25^[8] K
TW And B
Mass	0.325^[8] `M`_☉
Radius	3.20^[6] `R`_☉
Luminosity	14.5^[8] `L`_☉
Temperature	4658^[8] K
Other designations
HIP 262, 2MASS J00031822+3250451, SAO 53603, BD+32 4756, TYC 2263-975-1
Database references
SIMBAD	data

TW Andromedae (TW And) is an eclipsing binary star, classified also as an Algol variable star, in the constellation Andromeda. Its brightness varies with a period of 4.12 days, and has a typical brightness of magnitude 8.98 but decreasing down to a magnitude of 11.04 during the main eclipse.^[3]

TW Andromedae was discovered to be an Algol variable by August Kopff in 1909.^[9]

The TW Andromedae system is made of two stars in a circular orbit around their center of mass, with an orbital plane almost parallel to our line of sight. The presence of a third body in the system, with a minimum mass of 0.27 M_☉ and an orbital period of 49.6 years, has been proposed to account for the observed changes in the period of the variability.^[7]

Like in all Algol variable stars, when both stars of the system are aligned with respect to our line of sight, the furthest component blocks the light of the other, thus the apparent luminosity of the system diminishes. When the brightest component eclipses the other, a secondary, less pronounced minimum in the luminosity occurs.

References

^ Ammann, M.; Walter, K. (April 1973). "Photoelectric light curve of the Algol system TW Andromedae and the interpretation of its distortions by the effects of hot spots". Astronomy and Astrophysics. 24: 131. Bibcode:1973A&A....24..131A. Retrieved 6 October 2021.
^ ^a ^b ^c ^d ^e Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.
^ ^a ^b ^c ^d TW And, database entry, Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.), N. N. Samus, O. V. Durlevich, et al., CDS ID II/250 Accessed on line 2009-06-30.
^ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy & Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H.
^ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
^ ^a ^b ^c ^d ^e Rattenbury, N. J. (January 2009), "Microlensing of close binary stars", Monthly Notices of the Royal Astronomical Society, 392 (1): 439–447, arXiv:0810.2265, Bibcode:2009MNRAS.392..439R, doi:10.1111/j.1365-2966.2008.14074.x, S2CID 19012830.
^ ^a ^b ^c ^d ^e Kreiner, J. M.; Pribulla, T.; Tremko, J.; Stachowski, G. S.; Zakrzewski, B. (2008), "Period analysis of three close binary systems: TW And, TT Her and W UMi", Monthly Notices of the Royal Astronomical Society, 383 (4): 1506–1512, Bibcode:2008MNRAS.383.1506K, doi:10.1111/j.1365-2966.2007.12652.x.
^ ^a ^b ^c ^d ^e ^f Malkov, Oleg Yu (February 2020). "Semidetached double-lined eclipsing binaries: Stellar parameters and rare classes". Monthly Notices of the Royal Astronomical Society. 491 (4): 5489–5497. Bibcode:2020MNRAS.491.5489M. doi:10.1093/mnras/stz3363.
^ Kopff, August (December 1909). "Beobachtungen des Algolvariablen 21.1909 Andromedae (BD +32°4756)". Astronomische Nachrichten. 183 (7): 109. Bibcode:1909AN....183..109K. doi:10.1002/asna.19091830704. Retrieved 24 February 2023.

Constellation of Andromeda

Stars

Bayer	α (Alpheratz) β (Mirach) γ (Almach) δ ε ζ η θ ι κ λ μ ν ξ (Adhil) ο π ρ σ τ υ (Titawin) φ χ ψ ω A b c υ Per (Nembus)
Flamsteed	2 3 4 5 6 7 8 9 10 11 12 13 14 (Veritate) 15 18 22 23 26 28 32 36 39 41 44 45 47 55 56 58 59 63 64 65 66 6 Per
Variable	R T U W Z RT RV RX SU SW TU TW WZ XZ AB AC AD AE AF AR BM BX CC CG CN DS DX EG ET EU FF GP GQ GX GR GY HH HN IW KK KX KZ LL LN LP LQ OP OS OU PX PY QO QR QV QX V385 V428 V439 V455 V529 V807
HR	1 40 56 78 104 122 134 178 275 282 283 289 379 410 483 687 746 748 8884 8925 8950 8962 8973 9011 9074 9075 9105
HD	16175 (Buna) 222155
Other	3XMM J004232.1+411314 ADS 48 HAT-P-6 (Sterrennacht) HAT-P-16 HAT-P-19 HAT-P-28 M31-RV KELT-1 NGC 44 NGC 82 NGC 84 NGC 91 NGC 162 NGC 464 Qatar-3 Qatar-4 PA-99-N2 WASP-1 WISE 0146+4234 WISE J0005+3737 WISE J004945.61+215120.0

Exoplanets	14 Andromedae b κ Andromedae b υ Andromedae b c d Gliese 15 Ab c HD 13931 b HD 16175 b HAT-P-6b HAT-P-32b WASP-1b WASP-33b Qatar-4b Qatar-5b

Star
clusters

NGC	206 272 752 956 7686
Other	Mayall II RBC EXT8

Nebulae

NGC	7662

Galaxies

Messier	32 110
NGC	5 11 13 19 20 21 27 39 43 48 49 51 67 68 69 70 71 72 74 76 79 80 81 83 85 86 90 93 94 96 97 108 109 112 140 149 160 169 181 183 184 214 218 226 228 229 233 243 252 258 260 262 280 304 317 389 393 404 425 431 477 512 513 523 528 529 531 536 542 561 605 620 668 679 687 700 703 704 705 708 709 710 712 714 717 721 732 753 759 801 812 834 891 906 910 911 912 913 920 937 980 995 996 999 1000 7640 7836
Numbered	I II III IV V VIII IX X XI XVIII XIX XXI
Other	3C 66A 3C 66B Andromeda Galaxy Arp 273 Donatiello I