10 Lacertae: A Blistering, Brillant Hot Blue Double Star

The double-star system known as 10 Lacertae resides in Lacerta, the constellation of the lizard, a dim constellation visible in the autumn and winter nights. The sky lizard offers a rich collection of deep-sky objects, and 10 Lacertae is one of them. Compared to 8 Lacertae, with its well-known multiple bright blue stars, 12 Lacertae and 10 Lacertae are not as visually interesting, but they are still essential objects in astronomy.

Notably, 10 Lacertae’s brighter primary star is a hot, blue main-sequence star that is extremely massive and extremely hot, with a surface temperature of 32,000 Kelvin. Furthermore, 10 Lac was one of the first stars identified as O-type, and astronomers continue to use it as a reference point for these stars. The star’s life will not be long as it will burn through its fuel over a 10-million-year period and eventually go supernova.¹

The secondary companion star lies nearby at 62 arcseconds away.

My Observations

While not as alluring as 8 Lacertae with its star cluster-looking appeal, 10 Lac offers a nice blue double as I skim through this constellation. By how it looks, one could view 10 Lac as a twin system of 12 Lacertae, minus the fact that the secondary star in 10 Lac is brighter. Plus, there are a few more noticeable stars in my field of view.

Key Stats

Constellation	Lacerta
Best Viewing	Autumn
Visual Magnitude	+4.8 | +10.3
Absolute Visual Magnitude	-3.7
Distance from Earth	1,700 ly
Separation	62.6″
Orbital Period	Unknown
Milky Way Location	Orion Spur
My Viewing Grade	B
Designations	10 Lac, HR 8622, SAO 72575, HD 214680

Sources and Notes

¹Kaler, Jim. 10 Lacertae, http://stars.astro.illinois.edu/sow/10lac.html.

Sketch by Wayne McGraw