Alfa Lacertae

Alfa Lacertae (α Lac / 7 Lacertae / HD 213558) is the brightest star in the constellation Lacerta, the lizard, of apparent magnitude +3.76. It is 102 light-years away from the Solar System.

Alfa Lacertae is a white star of the main sequence of spectral type A1V with a surface temperature of 9200 K. Its luminosity is equivalent to 27 suns and its radius is twice the solar radius. Of physical characteristics similar to the well-known Sirius, its smaller brightness is consequence of the distance, since it is about twelve times farther than this one. The rotation speed of Alfa Lacertae is at least 146 km / s, completing a turn in less than 17 hours. With a double mass the solar mass is thought to be a relatively young star, which has recently started hydrogen fusion entering the main sequence.

A star of magnitude 12 to 36 seconds of arc is not a real companion and forms a double optics next to Alfa Lacertae. It is also a white star (type A5) but about 27 times further.

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