Albireo, a pretty pair: Stable stellar marriage or celestial one-night stand?

Gaia DR2 has added new aspects to a century-old question: Is Albireo (beta Cygni) a physical or an optical double? Albireo is well known both among amateur and professional astronomers, and it is often called ``the most beautiful double star in the whole sky.”

Therefore a twitter message of August 2018 by a US science writer, claiming that Gaia DR2 says it is a ``fake double” (i.e. an optical double), raised considerable interest in both communities.

My attempt to clarify the soundness of that claim quickly led to two papers: A&A, Vol. 620, L2 (4 pages), RNAAS, Vol. 2, No. 4 (3 pages).

Read the full amusing story in the two original papers, or – if you know German – in a more entertaining form in “Sterne und Weltraum”, issue 4/2019, pages 36-44.