Volume 620, December 2018
|Number of page(s)||4|
|Section||Letters to the Editor|
|Published online||26 November 2018|
Letter to the Editor
The mass of Albireo Aa and the nature of Albireo AB
New aspects from Gaia DR2
Zentrum für Astronomie (Center for Astronomy), Heidelberg University, Mönchhofstr. 14, 69120 Heidelberg, Germany
2 Internationale Amateursternwarte e.V. (International Amateur Observatory Ass.), Grevenkamp 5, 24161 Altenholz, Germany
Accepted: 31 October 2018
Aims. We aim to clarify the nature of Albireo AB and specifically to decipher whether it is an optical or physical pair. We also try to determine the mass of Albireo Aa.
Methods. We scrutinize and compare the available absolute astrometric data (from HIPPARCOS and Gaia DR2) of Albireo A and B, and we investigate the relative orbit of the pair Albireo Aa,Ac using orbit solutions based on ground-based interferometric measurements.
Results. The mass of Albireo Aa (K3 II) is surprisingly small; only an upper limit of about 0.7 M⊙ could be derived. The systemic proper motion of Aa,Ac differs from that of component B by about 10 mas year−1 with an uncertainty of less than 2 mas year−1. Albireo AB is therefore most probably an optical double.
Conclusions. Specific astrometric and spectroscopic follow-up observations clarifying the surprising mass estimate for Albireo Aa are recommended.
Key words: stars: fundamental parameters / binaries: general / stars: individual: Albireo / stars: individual: β Cyg / proper motions / parallaxes
© ESO 2018
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.