Lacerta
Lacerta is one of the 88 modern constellations defined by the International Astronomical Union. Its name is Latin for lizard. A small, faint constellation, it was defined in 1687 by the astronomer Johannes Hevelius. Its brightest stars form a "W" shape similar to that of Cassiopeia, and it is thus sometimes referred to as 'Little Cassiopeia'. It is located between Cygnus, Cassiopeia and Andromeda on the northern celestial sphere. The northern part lies on the Milky Way.
Lacerta is typical of Milky Way constellations: no bright galaxies, nor globular clusters, but instead open clusters, for example NGC 7243, the faint planetary nebula IC 5217 and quite a few double stars. It also contains the prototypic blazar BL Lacertae. Lacerta contains no Messier objects.
Alpha Lacertae is a blue-white hued main-sequence star of magnitude 3.8, 102 light-years from Earth. It has a spectral type of A1 V and is an optical double star. Beta Lacertae is far dimmer, a yellow giant of magnitude 4.4, 170 light-years from Earth.[1]
ADS 16402 is a binary star system in Lacerta, around which a planet orbits with some unusual properties.[2] The Jupiter-sized planet exhibits an unexpectedly low density, about the same as cork. This planet is dubbed HAT P-1.
EV Lacertae is a rapidly spinning magnitude 10 red dwarf with a strong magnetic field. It is a flare star that can emit powerful flares potentially visible to the naked eye, thousands of times more energetic than any from Earth's sun.
HD 215441 (22h 44m.2 / +55° 35') is known as Babcock's Magnetic Star. Source: Sky Catalogue 2000.0 Volume 2: Double Stars, Variable Stars and Nonstellar Objects, page xlv, chapter Glossary of Selected Astronomical Names.
