Theta Lyrae is a star in a trinary star system, in the constellation Lyra, approximately 770 light years away from Earth

Earth

Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

. Theta Lyrae is an orange bright giant

Bright giant

The luminosity class II in the Yerkes spectral classification is given to bright giants. These are stars which straddle the boundary between giants and supergiants, and the classification is in general given to giant stars with exceptionally high luminosity, but which are not sufficiently bright...

 star of the spectral type K0II, meaning it possesses a surface temperature of about 5,000 kelvins, and is many times bigger and brighter, yet cooler, than our Sun

Sun

The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

.

It is orbited by a subsystem composed of BD+37° 3399 and BD+37° 3399B. 10th magnitude BD+37° 3399 is a giant star

Giant star

A giant star is a star with substantially larger radius and luminosity than a main sequence star of the same surface temperature. Typically, giant stars have radii between 10 and 100 solar radii and luminosities between 10 and 1,000 times that of the Sun. Stars still more luminous than giants are...

with a spectral type of K2III. It is therefore almost the same temperature as Theta Lyrae, but smaller and dimmer. BD+37° 3399B is an 11th magnitude star of an unknown spectral type.