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 created 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 slithers between Cygnus, top right, and the obsolete constellation of Honores Friderici (now part of Andromeda), bottom, as seen on Chart IV in the Uranographia of Johann Bode (1801).
[http://www.ianridpath.com/startales/lacerta.htm]
Centered on a region of the sky without apparently bright stars, Lacerta was apparently not regarded as a constellation by ancient Western astronomers. Johannes Hevelius created the constellation in 1687 and initially christened it ‘Stellio’ (the stellion), a newt with star-like dorsal spots found along the Mediterranean coast.
Other Europeans who sought to name this new constellation included Augustin Royer, who created Sceptrum et Manus Iustitiae (the Hand of Justice and Sceptre) to honor Louis XIV in 1670, and Johann Elert Bode, who created Frederici Honores (Frederick’s Glory) to honor Frederick the Great in 1787. Both Sceptrum and Frederici Honores are now obsolete, while Lacerta still survives.
Although not included in ancient star charts of Europe and the Near East, the stars of Lacerta, along with some in the eastern portion of Cygnus, were coincidentally combined by early Chinese astronomers into their ‘Flying Serpent.’ Similarly, the Chumash people of California call this part of the sky ‘Lizard’ and include it in multiple stories.
[http://www.dibonsmith.com/lac_con.htm]
[http://www.davidmalin.com/fujii/source/Lac.html]
Lacerta’s brightest star, 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. The visual companion, CCDM J22313+5017B, of spectral type A and apparent visual magnitude 11.8, is approximately 36 arcseconds away.
[https://en.wikipedia.org/wiki/Alpha_Lacertae]
Beta Lacertae is far dimmer, a yellow giant of magnitude 4.4, 170 light-years from Earth.
EV Lacertae (EV Lac, Gliese 873, HIP 112460) is a faint red dwarf star 16.5 light years away in the constellation Lacerta. It is the nearest star to the Sun in that region of the sky, although with an apparent magnitude of 10, it is only barely visible with binoculars.
EV Lacertae is spectral type M3.5 flare star that emits X-rays. On 25 April 2008, NASA’s Swift satellite picked up a record-setting flare from EV Lacertae. This flare was thousands of times more powerful than the largest observed solar flare. Because EV Lacertae is much farther from Earth than the Sun, the flare did not appear as bright as a solar flare. The flare would have been visible to the naked eye if the star had been in an observable part of the night sky at the time. It was the brightest flare ever seen from a star other than the Sun.
This star is much younger than the Sun, its age is estimated at 300 million years. The fast spin, together with its convective interior, produces a magnetic field that is much more powerful than the Sun's. This strong magnetic field is believed to play a role in the star's ability to produce such bright flares:
[https://en.wikipedia.org/wiki/EV_Lacertae]
Pipsqueak star unleashes monster flare
For many years scientists have known that our sun gives off powerful explosions, known as flares, that contain millions of times more energy than atomic bombs.
But when astronomers compare flares from the sun to flares on other stars, the sun’s flares lose. On April 25, 2008, NASA’s Swift satellite picked up a record-setting flare from a star known as EV Lacertae. This flare was thousands of times more powerful than the greatest observed solar flare. But because EV Lacertae is much farther from Earth than the sun, the flare did not appear as bright as a solar flare. Still, it was the brightest flare ever seen from a star other than the sun.
What makes the flare particularly interesting is the star. EV Lacertae is much smaller and dimmer than our sun. In other words, a tiny, wimpy star is capable of packing a very powerful punch.
How can such a small star produce such a powerful flare? The answer can be found in EV Lacertae’s youth. Whereas our sun is a middle-aged star, EV Lacertae is a toddler. The star is much younger than our sun, and is still spinning rapidly. The fast spin, together with its churning interior, whips up gases to produce a magnetic field that is much more powerful than the sun's magnetic field.
[https://www.nasa.gov/multimedia/imagegallery/image_feature_1087.html]
ADS 16402: In this double of two sunlike stars one of the pair is orbited by an enormous bloated gas planet. This planet, designated as HAT-P-1, has 1.38 times the diameter of Jupiter, but only about half of its mass. It orbits its star every 4.5 days in a distance of 0.05 AU.
[https://jumk.de/astronomie/exoplanets/ads-16402.shtml]
ADS 16402 is a binary star system, composed of two sun-like stars located 450 light-years away in the constellation Lacerta. It was first identified by John Herschel in 1831. The two stars are separated by 1500 AUs. The star system is estimated to be 1.9 ± 0.6 billion years old. The secondary star ADS 16402 B is also designated HAT-P-1.
On September 14, 2006 the HATNet Project announced their first extrasolar planet discovery HAT-P-1b, a hot Jupiter type gas giant in orbit around the secondary star ADS 16402B. Following the designation scheme used by the HATNet Project, the secondary star is known as HAT-P-1, and the planet itself designated HAT-P-1b.
[https://en.wikipedia.org/wiki/ADS_16402]
Lacerta is typical of Milky Way constellations: no bright galaxies, nor globular clusters, but instead open clusters, for example NGC 7243:
NGC 7243
NGC 7243, also Caldwell 16, is an open cluster and Caldwell object. It shines at magnitude +6.4. Its celestial coordinates are RA 22h 15.3m, dec +49° 53′. It is located near the naked-eye stars Alpha Lacertae, 4 Lacertae, an A-class double star, and planetary nebula IC 5217. It lies approximately 2,800 light-years away, and is thought to be just over 100 million years old, consisting mainly of white and blue stars.
[https://en.wikipedia.org/wiki/NGC_7243]
Lacerta also contains the prototypic blazar BL Lacertae. This is a highly variable, extragalactic AGN (active galactic nucleus or active galaxy), at a distance of 900 million light years. Due to its early discovery, BL Lacertae became the prototype and namesake of the class of active galactic nuclei known as ‘BL Lac objects:’
[https://en.wikipedia.org/wiki/BL_Lacertae]
BL Lacertae
A BL Lacertae object (BL Lac object) is a type of active galactic nucleus (AGN) characterized by a nearly featureless spectrum (i.e., virtually devoid of spectral lines), rapid, marked variability at radio, infrared, and optical wavelengths (often by several magnitudes over a few days or weeks), and strong, variable polarization at radio and optical wavelengths. The prototype, in the constellation Lacerta, was originally classified as a variable star.
BL Lac objects belong to the category of AGN now known as blazars and are believed to be essentially quasars viewed directly down the axis of their powerful jets.
[http://www.daviddarling.info/encyclopedia/B/BL_Lacertae_object.html]
[https://en.wikipedia.org/wiki/Lacerta
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