The spectroscopic binary eta Andromedae: Determination of the orbit by optical interferometry
1993; Institute of Physics; Volume: 106; Linguagem: Inglês
10.1086/116816
ISSN1538-3881
AutoresC. A. Hummel, J. T. Armstrong, A. Quirrenbach, David F. Buscher, David Mozurkewich, R. Simon, K. J. Johnston,
Tópico(s)Astrophysics and Star Formation Studies
ResumoWe have determined the following orbital elements of the double-lined spectroscopic binary eta Andromedae (combined spectral class G8 IIIb) using measurments with the Mark III long baseline optical interferometer on Mt. Wilson: Period P = 115.72 +/- 0.02d, major axis a = 10.37 +/- 0.03 milliarcseonds, eccentricity e = 0.006 +/- 0.002, epoch of periastron T = JD 2448013 +/- 2, inclination i = 30.5 deg +/- 0.4 deg, argument of ascending node omega = 69.4 deg +/- 0.6 deg, and argument of periastron omega = 215 deg +/- 7 deg. The magnitude differences of the two components measured at lambda lambda 800 nm, 550 nm, and 500 nm are 0.50 mag +/- 0.06 mag, 0.55 mag +/- 0.08,ag, and 0.56 mag +/- 0.09 mag, respectively. Using orbital elements from spectroscopy by Gordon (1946) we derive component masses of (2.59 +/- 0.30) solar mass and (2.34 +/- 0.22) solar mass, and a distance of (76 +/- 2)pc. Monte-Carlo simulations have been performed to estimate parameter uncertainties. We discuss the evolutionary state of eta Andromedae.
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