The distance is essentially unknown. Assumptions about the luminosity have been used to estimate the distance and other stellar parameters. At an assumed kinematical distance of4.9 kpc, the luminosity is 8,300 L☉ and the radius 58 R☉.[3] The star was originally at least 2.5 M☉ and is now 0.63 M☉.[5] Assuming a luminosity of 3,500 L☉, the distance becomes1.5 kpc.[7] Estimates based on the oxygenspectral line strengths give much higher values luminosities with anabsolute magnitude of at least −8.[4]
In 2006, Vera P. Arkhipovaet al. announced that IRAS 19475+3119 is avariable star.[8] It was given itsvariable star designation, V2513 Cygni, in 2013.[9] The star varies from aboutmagnitude 9.33 to 9.50. A primary period of 41 days has been determined, but a slightly shorter secondary period leads to longbeats causing variations in the amplitude and apparent period from year to year. The variations are caused bystellar pulsations, with the star being brightest when it is hottest. Thetemperature varies by up to400 K.[10]
^abSamus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)".VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S.1.Bibcode:2009yCat....102025S.
