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Alpha Lacertae may be the brightest of the stars in the constellation of Lacerta, but it has little competition among this faint group - its apparent magnitude is just +3.8. It lies more than a hundred light years from the Solar System.

Physically, Alpha Lacertae is a main sequence star and, like most stars (including our own Sun), generates energy through the fusion of hydrogen into helium. It is, however, about ten times as massive as the Sun, and consequently much more luminous. It has a high surface temperature of c.10,000 K, and so shines with a fierce white light. Alpha Lacertae is a binary system: the main white star has an orbiting companion, which is much fainter at magnitude +12.0.

From Earth, Alpha Lacerta lies in the northern part of its home constellation of Lacerta, against the backdrop of the Milky Way. It can prove difficult to pick out, since it is not noticeably brighter than many of its neighbouring stars; it forms the second point in the descending 'zig-zag' that forms the backbone of the Lizard. Lacerta itself occupies the faint space between Andromeda and Cygnus, and is best observed in August and September.


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