IRAS 19475+3119

IRAS 19475+3119 is a protoplanetary nebula in the constellation of Cygnus, 15,000 light-years away. The central star, V2513 Cygni, is an F-type post-AGB star.

The brightest portion of the nebula shows a quadrupolar structure, with elongated bipolar lobes, all surrounded by a faint halo.

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 of $4.9 kpc$, the luminosity is and the radius. The star was originally at least and is now. Assuming a luminosity of, the distance becomes $1.5 kpc$. Estimates based on the oxygen spectral line strengths give much higher values luminosities with an absolute magnitude of at least −8.

The central star is variable, from about magnitude 9.33 to 9.50. A primary period of 41 days has been determined, but a slightly shorter secondary period leads to long beats causing variations in the amplitude and apparent period from year to year. The variations are caused by stellar pulsations, with the star being brightest when it is hottest. The temperature varies by up to $400 K$.