1994A&A...285..535M

A new spectroscopic orbit is presented for the Algol system AT Peg (HD 210892, P=1.146 days, α(2000.0)=22h13.4m, δ=+8deg25.5', A4V+G). We find : m_p sin ³i=2.04±0.06M_☉, m_s sin ³i=0.96±0.025M_☉, (a_p+a_s)sin i=4.62 ±0.06 x 10⁶km, m_p/m_s=2.115±0.04. This is the first direct measure of the mass ratio for this system. The new mass ratio is used to solve the single colour light curve of Cristaldi & Walter (1963). We find the following absolute parameters: m_p=2.22±0.065 M_☉, m_s=1.05±0.025M_☉, <R_p ≥1.86±0.025R_☉, <R_s ≥2.15± 0.03R , <T_p ≥ 8400±100K, < T_s ≥4900±200 K. The spectral type of the primary was established from a spectrum of the primary reconstructed from the spectroscopic data set using tomography. AT Peg is slightly reddened (E(B-V)=0.03±0.03) at a distance of 360±20parsecs.