The Cepheid AW Per is a component in a multiple system with a long period orbit. The radial velocities of Griffin (2016) cover the 38 year orbit well. An extensive program of interferometry with the CHARA array is reported here, from which the long period orbit is determined. In addition, a {\it Hubble Space Telescope} high resolution spectrum in the ultraviolet demonstrates that the companion is itself a binary with nearly equal mass components. These data combined with a distance from {\it Gaia} provide a mass of the Cepheid (primary) of M1 = 6.79 ± 0.85 M⊙. The combined mass of the secondary is MS = 8.79 ± 0.50 M⊙. The accuracy of the mass will be improved after the fourth Gaia data release expected in approximately two years.
@article{arxiv.2406.17881,
title = {The Orbit and Mass of the Cepheid AW Per},
author = {Nancy Remage Evans and Alexandre Gallenne and Pierre Kervella and Antoine Mérand and John Monnier and Richard I Anderson and H. Moritz Günther and Charles Proffitt and Elaine M. Winston and Grzegorz Pietrzynski and Wolfgang Gieren and Joanna Kuraszkiewicz and Narsireddy Anugu and Rachael M. Roettenbacher and Cyprien Lanthermann and Mayra Gutierrez and Gail Schaefer and Benjamin R. Setterholm and Noura Ibrahim and Stefan Kraus},
journal= {arXiv preprint arXiv:2406.17881},
year = {2024}
}