HD 195564 is a binary star in the southern constellation of Capricornus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.65. Parallax measurements give us an estimate of its distance as 81 light years.
Based upon the spectrum of light emitted by the primary, it has a stellar classification of G2.5IV. This indicates that it is a G-type subgiant that has exhausted the hydrogen in its core region. It has a mass of 1.242 times the mass of the Sun, but a measured radius that is 1.894 times as large. As a result, it shines with 2.986 times the luminosity of the Sun. The abundance of elements in this star is similar to that in the Sun, although it is an older star with an age of around 8.2 billion years. The effective temperature of the stellar atmosphere is 5,514 K, giving it the yellow-hued glow of an ordinary K-type star.
The secondary companion has an apparent magnitude of 11.30, and a mass just 55% that of the Sun. The pair orbit each other with an estimated period of around 620 years, following a highly-eccentric path.
In a paper published in April 2017, a candidate planet was found orbiting HD 195564 A with a period of .
References