Omicron Herculis is a multiple star system

Star system

A star system or stellar system is a small number of stars which orbit each other, bound by gravitational attraction. A large number of stars bound by gravitation is generally called a star cluster or galaxy, although, broadly speaking, they are also star systems.-Binary star systems:A stellar...

 in the constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 Hercules

Hercules (constellation)

Hercules is a constellation named after Hercules, the Roman mythological hero adapted from the Greek hero Heracles. Hercules was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations today...

. It has the traditional name Atia and the Flamsteed designation

Flamsteed designation

Flamsteed designations for stars are similar to Bayer designations, except that they use numbers instead of Greek letters. Each star is assigned a number and the Latin genitive of the constellation it lies in...

 103 Herculis.

Properties

Omicron Herculis is a B9.5V star approximately 106 pc from the Earth. It has an apparent magnitude of 3.83, and an absolute magnitude of -1.29. The star burns bluish-white, and has a luminosity approximately 180x as bright as the sun. Omicron Herculis is 3.32 solar masses.

Omicron Herculis is an eruptive variable of the Gamma Cassiopeia class, which are rapidly rotating B-class stars with mass outflow.

Omicron Herculis is both a spectroscopic and an interferometric binary star with a separation of 0.1 arcsec.

Brightest star

Omicron Hercules is notable for being the direction in which the Sun's proper motion is directed. It will eventually become the brightest star in the sky in approximately 3 million years from today, at -0.4, slightly less bright than Canopus.

Starbox Info

Omicron Herculis, o Her

RA 18,07,32.60

DEC +28.45.45.0

B9.5Ve

0.03 B/V

Gamma Cassiopeia Variable

0.001 RA Proper Motion

0.009 DEC Proper Motion

0.005 arcsec Parallax

distance of 106 pc

-1.30 Absolute magnitude

mass=3.2 Sol

radius=2.5 Sol

luminosity=180 Sol

temperature=11,500

metal=?

rotational_velocity=134 km/s

age=?

See also

• Lists of stars in the constellation Hercules
• Spectral type B