Luminosity (bolometric) 145,000 L☉ | ||
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RW Cygni (RW Cyg / HIP 101023 / BD + 39 4208) is a variable star in the constellation Cygnus. Its average apparent magnitude is +8.81, and the star is about 75 arcseconds west of Bright Sadr (γ Cygni).
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Distance
A member of the Stellar Association OB9, the satellite Hipparcos (1.28 milliarcseconds) places RW Cygni about 2,550 light years from the solar system. Another study, however, raises this figure to 3,600 light-years.
Characteristics
RW Cygni is a red supergiant of spectral type M2-4Ia-Iab with an effective temperature of 3,920 K. It is a large supergiant, with a radius between 680 - 980 solar radii. Using the more conservative figure, so if it is placed in the center of Solar System, it would be extend past the orbit of Mars. However, it is surpassed in size by other stars like KY Cygni, NML Cygni or BC Cygni, the latter also in the constellation Cygnus. With a mass of about 20 solar masses, it is estimated that their stellar mass loss in powder form is 3.2 × 10-9 solar masses per year.
Billed as a semiregular variable star SRC, RW Cygni brightness varies from magnitude +8.0 and +9.5 with a period of approximately 580 ± 80 days.