Several other faint stars within about an
arc-minute have been listed as companions, but none are physically associated with ζ1 Lyrae.[14]
Binary system
This is a single-lined
spectroscopic binary system with an
orbital period of 4.3 days and a nearly circular orbit with an
eccentricity of 0.01.[5] The primary, component A, is an
Am star with a
stellar classification of kA5hF0mF2. This complex notation indicates that the spectral type determined solely from the
calcium K line would be A5, the spectral type determined from other metallic lines would be F2, and the type determined from hydrogen lines would be F0.[3]
Variability
ζ1 Lyrae appears to be slightly variable, with a frequency of 0.65256 cycles per day and an amplitude of 0.0032 in magnitude.[15] The star has an estimated 2.36[6] times the
mass of the Sun and around 2.5[7] times the
Sun's radius. The position of this system is associated with an
X-ray source with a
luminosity of 571.6×1020 W.[16]
^
abcdMermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data,
SIMBAD,
Bibcode:
1986EgUBV........0M.
^
abAbt, Helmut A.; Morrell, Nidia I. (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135,
Bibcode:
1995ApJS...99..135A,
doi:10.1086/192182.
^Campbell, W. W.; Curtis, H. D. (1905), "A list of nine stars whose radial velocities vary", The Astrophysical Journal, 21: 189,
Bibcode:
1905ApJ....21..185C,
doi:
10.1086/141200.
^Jordan, Frank Craig (1910), "The orbit of ζ1 Lyrae", Publications of the Allegheny Observatory of the University of Pittsburgh, 1 (17): 115–118,
Bibcode:
1910PAllO...1..115J.
^Mason, Brian D.; et al. (December 2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471,
Bibcode:
2001AJ....122.3466M,
doi:10.1086/323920.