1993/12/01 by C. A. Hummel, J. T. Armstrong, A. Quirrenbach +4 · 5 citations
Physics and Astronomy · #Stellar, planetary, and galactic studies #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies
paper · doi:10.1086/116816
openalex publication_date 1993/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/26
We 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.