The mass of Albireo Aa and the nature of Albireo AB

• Verfasst von: Bastian, Ulrich [VerfasserIn]
• Verfasst von: Anton, Rainer [VerfasserIn]
• Titel: The mass of Albireo Aa and the nature of Albireo AB
• Titelzusatz: new aspects from Gaia DR2
• Verf.angabe: U. Bastian, R. Anton
• Fussnoten: Gesehen am 13.02.2019
• Titel Quelle: Enthalten in: Astronomy and astrophysics
• Jahr Quelle: 2018
• Band/Heft Quelle: 620(2018) Artikel-Nummer L2, 4 Seiten
• ISSN Quelle: 1432-0746
• DOI: doi:10.1051/0004-6361/201834351
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1587600560

Abstract

<i>Aims.<i/> 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.<i>Methods.<i/> We scrutinize and compare the available absolute astrometric data (from HIPPARCOS and <i>Gaia<i/> 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.<i>Results.<i/> The mass of Albireo Aa (K3 II) is surprisingly small; only an upper limit of about 0.7 <i>M<i/><sub>⊙<sub/> could be derived. The systemic proper motion of Aa,Ac differs from that of component B by about 10 mas year<sup>−1<sup/> with an uncertainty of less than 2 mas year<sup>−1<sup/>. Albireo AB is therefore most probably an optical double.<i>Conclusions.<i/> Specific astrometric and spectroscopic follow-up observations clarifying the surprising mass estimate for Albireo Aa are recommended.