TW Andromedae

TW Andromedae

The visual band light curve of TW Andromedae, plotted from data published by Ammann & Walter[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 00h 03m 18.22724s[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 (Rv)−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]
Distance1,020 ± 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
Mass1.685[8] M☉
Radius2.05[6] R☉
Luminosity4.3[8] L☉
Temperature7250±25[8] K
TW And B
Mass0.325[8] M☉
Radius3.20[6] R☉
Luminosity14.5[8] L☉
Temperature4658[8] K
Other designations
HIP 262, 2MASS J00031822+3250451, SAO 53603, BD+32 4756, TYC 2263-975-1
Database references
SIMBADdata

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.

  1. ^ Cite error: The named reference Ammann was invoked but never defined (see the help page).
  2. ^ 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.
  3. ^ a b c d Cite error: The named reference GCVS was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference TYCHO was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference rv was invoked but never defined (see the help page).
  6. ^ a b c d e Cite error: The named reference Rattenbury2009 was invoked but never defined (see the help page).
  7. ^ a b c d e Cite error: The named reference Kreiner2008 was invoked but never defined (see the help page).
  8. ^ 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.
  9. ^ Cite error: The named reference Kopff1909 was invoked but never defined (see the help page).