Based upon the spectrum of light emitted by the primary, it has a stellar classification of G2.5IV.[4] This indicates that it is a G-typesubgiant that has exhausted the hydrogen in its core region. It has a mass of 1.242 times the mass of the Sun,[6] but a measured radius that is 1.867 times as large.[7] As a result, it shines with 2.705 times the luminosity of the Sun.[7] 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 8.2billion years.[7] The effective temperature of the stellar atmosphere is 5,421K,[7] giving it the yellow-hued glow of an ordinary K-type star.[11]
The secondary companion has an apparent magnitude of 11.30,[12] and a mass just 55% that of the Sun.[13] The pair orbit each other with an estimated period of around 620 years, following a highly-eccentric path.[6]
In a paper published in April 2017, a candidate planet was found orbiting HD 195564 A with a period of 5,404 days (14.80yr).[14]
1234Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
12Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins Catalog of Revised MK Types for the Cooler Stars". The Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
12345An, Qier; Brandt, Timothy D.; Brandt, G. Mirek; Venner, Alexander (October 2025), "Orbits and Masses for 156 Companions from Combined Astrometry and Radial Velocities, and a Validation of Gaia Non-single-star Solutions", The Astrophysical Journal Supplement Series, 280 (2): 61, arXiv:2508.08374, Bibcode:2025ApJS..280...61A, doi:10.3847/1538-4365/adfa99, ISSN0067-0049.
