VV Cephei is a naked eye binary star located 4,900 light years away in the Cepheus constellation.
VV Cephei A Edit
VV Cephei is an eclipsing binary with the second longest known eclipses. The system can be seen with the naked eye, but the components cannot be visually separated without a large telescope. A red supergiant fills its roche lobe, while matter is being pulled away from it towards VV Cephei B. VV Cephei A is a red supergiant (not a hypergiant because it isn't luminous enough) with a disputed diameter. It ranges from 1,050 solar diameters (1,462,423,200 km) to 1,900 solar diameters (2,644,769,600 km). However, it is very unlikely to reach 1,900 solar radii, since it has a roche lobe that estimated to be 1,800 solar radii (2,507,011,200 km). If it were placed in the center of our solar system, it would extend past the orbit of Jupiter. It has a mass 2.5 to 18.2 times that of our sun (Once thought to be 100 solar masses), a luminosity 200,000 times greater, and its temperature is 3,826 K. Its age is unknown, but it is still one of the largest stars known.
VV Cephei B Edit
VV Cephei B takes matter from VV Cephei A, forming a torus around itself. It has a diameter 13 (18,106,192 km) to 25 (34,819,600 km) times that of our sun. It is a Be main sequence star and was discovered by Dean McLaughlin in 1936. It would be larger than the HD 209458 system (HD 209458 b has an orbit 9.7 times the sun's diameter), but not the orbit of any solar system planet. Its mass is 8 to 18.4 times that of our sun, and its age is 25 million years. Its luminosity is unknown.