RT Persei is a variable star system in the northern constellation of Perseus, abbreviated RT Per. It is an eclipsing binary system with an orbital period of 0.84940032 d (20.386 h). At peak brightness the system has an apparent visual magnitude of 10.46, which is too faint to be viewed with the naked eye. During the eclipse of the primary this decreases to magnitude 11.74, then to magnitude 10.67 with the secondary eclipse.[3] The distance to this system is approximately 628 light years based on parallax measurements.[2] It is drifting closer with a heliocentric radial velocity of about −12 km/s.[5]
This is a semidetached binary system with a circular orbit where the secondary component is filling its Roche lobe and losing mass.[7] The primary component is an F-type main-sequence star with a stellar classification of F5V.[4] It has 1.08 times the mass of the Sun, 1.20 times the Sun's radius,[15] and is close to filling its Roche lobe.[7] The secondary is a more evolvedsubgiant star with a class of G7IV.[4] It has just 30% of the Sun's mass but has expanded to 108% of the solar radius.[15]
The system has undergone irregular jumps in orbital period, which are common among Algol-type variables that are exchanging mass and angular momentum. Measured decreases in the period may be variously explained by spin-orbit coupling and interaction of the stellar magnetic fields.[15] Based upon long-term trends in the light curve, an unseen third component is moving in an elliptical orbit with the inner pair over a period of 41.9 years. It is estimated to be orbiting at a distance of at least 2.67 AU with an eccentricity (ovalness) of 0.34.[15]
^ abcdeMalkov, Oleg Yu (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.
^ abWilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Washington, Carnegie Institute of Washington, D.C., Bibcode:1953GCRV..C......0W.
^Dugan, Raymond Smith (1911), "The Algol-System RT Persei", Contributions from the Princeton University Observatory, 1: 3–47, Bibcode:1911CoPri...1....3D.
^Dugan, Raymond Smith (1938), "Further Observations of RT Persei and an Attempted Explanation of the Change in Period", Contributions from the Princeton University Observatory, 17: 1–14, Bibcode:1938CoPri..17....1D.
^ abcdeQian, Shengbang (November 2001), "Possible Mass and Angular Momentum Loss in Algol-Type Binaries. V. RT Persei and TX Ursae Majoris", The Astronomical Journal, 122 (5): 2686–2691, Bibcode:2001AJ....122.2686Q, doi:10.1086/323455, S2CID121698690.
Sanwal, B. B.; Chaubey, U. S. (December 1979), "On the lightcurve and orbital elements of binary star RT Persei", Bulletin of the Astronomical Society of India, 7: 118, Bibcode:1979BASI....7..118S.
Todoran, I. (October 1979), "Period Changes of RT Persei", Information Bulletin on Variable Stars, 1687: 1, Bibcode:1979IBVS.1687....1T.
Mancuso, S.; Milano, L. (February 1976), "Photoelectric V Light Curve of the Eclipsing Binary RT Persei", Information Bulletin on Variable Stars, 1102: 1, Bibcode:1976IBVS.1102....1M.