RT Andromedae

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RT Andromedae
RT Andromedae system.png
RT Andromedae system.
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Andromeda
Right ascension 23h 11m 10.099s[1]
Declination +53° 01′ 33.04″[1]
Apparent magnitude (V) +9.03
Spectral type G0V / K2V
Variable type RS Canum Venaticorum variable
Proper motion (μ) RA: -7.01 ± 0.79[1] mas/yr
Dec.: -20.80 ± 0.77[1] mas/yr
Distance 270.7 ± 6.5 ly
(83 ± 2 [2] pc)
Mass 1.1/0.83[2] M
Radius 1.25/0.9[3] R
Luminosity 1.8/0.35 L
Temperature 5900/4674[2] K
Age 4.54 billion years
Period (P) 0.001723 yr
Semi-major axis (a) 0.01635 AU
Eccentricity (e) 0.011
Inclination (i) 87.6[2]°
Other designations
RT And, GSC 03998-02167, HIP 114484, TYC 3998-2167-1, BD+52° 3383a, GCRV 14555, 2MASS J23111009+5301330
Database references

RT Andromedae is a variable star in the constellation of Andromeda. It is classified as a RS Canum Venaticorum variable, a type of close eclipsing binary star, and varies from an apparent visual magnitude of 9.83 at minimum brightness to a magnitude of 8.97 at maximum brightness, with a period of 0.6289216 days.[4]

Presence of a third body[edit]

According to Pribulla et al. (2000), a third object could be present in the system. The minimum mass is estimated at 5 percent of Solar mass (roughly 50 times the mass of Jupiter), the orbital period at close to 85 years and eccentricity is inferred to be high (e=0.56).[2] Such an object could likely turn out to be a brown dwarf or even a massive jovian planet. However, a recent paper of Manzoori (2009) states that the minimum mass of the third body is likely to be close to 0.6 Solar masses, making the object stellar rather than substellar.[5] Also, the orbital period has turned out to be more than 85 years.

The RT Andromedae planetary system[5]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b (retracted) ≥50-600 MJ ≈25 85-105 0.56


  1. ^ a b c d van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. Bibcode:2007A&A...474..653V. arXiv:0708.1752Freely accessible. doi:10.1051/0004-6361:20078357.  Vizier catalog entry
  2. ^ a b c d e Pribulla; et al. (2000). "Active eclipsing binary RT Andromedae revisited". Astronomy & Astrophysics. 362: 169–188. Bibcode:2000A&A...362..169P. 
  3. ^ Dryomova; Perevozkina, E.; Svechnikov, M. (2005). "Catalogue of the orbital elements, masses, and luminosities for short-periodic RS CVn-type eclipsing systems". Astronomy & Astrophysics. 437 (1): 375–381. Bibcode:2005A&A...437..375D. doi:10.1051/0004-6361:20042003. 
  4. ^ RT 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 2009-06-22.
  5. ^ a b Manzoori (2009). "Cyclic Variations of Orbital Period and Long-Term Luminosity in Close Binary RT Andromedae". The Astronomical Journal. 138 (6): 1917–1924. Bibcode:2009AJ....138.1917M. doi:10.1088/0004-6256/138/6/1917.