σ Herculis (sigma Herculis)
σ Herculis is a variable and double main-sequence star in the constellation of Hercules.
σ Herculis visual magnitude is 4.2. Because of its moderate brightness, σ Herculis should be easily visible from locations with dark skyes, while it can be barely visible, or not visible at all, from skyes affected by light pollution.
The table below summarizes the key facts about σ Herculis:
Celestial coordinates and finder chart of σ Herculis
σ Herculis is situated north of the celestial equator, as such, it is more easily visible from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of σ Herculis are provided in the following table:
The simplified sky map below shows the position of σ Herculis in the sky:
Visibility of σ Herculis from your location
Location: Greenwich, United Kingdom
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
σ Herculis (sigma Herculis) is circumpolar and transits at 00:05 UTC (altitude: 81.0°)
Digitized Sky Survey image of σ Herculis
The image below is a photograph of σ Herculis from the Digitized Sky Survey 2 (DSS2 - see the credits section) taken in the red channel. The area of sky represented in the image is 0.5x0.5 degrees (30x30 arcmins). The proper motion of σ Herculis is -0.011 arcsec per year in Right Ascension and 0.046 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.
Distance of σ Herculis from the Sun and relative movement
σ Herculis is distant 302.13 light years from the Sun and it is moving towards the Sun at the speed of 11 kilometers per second.
Spectral properties of σ Herculis
σ Herculis belongs to spectral class B9 and has a luminosity class of V corresponding to a main-sequence star.
The red dot in the diagram below shows where σ Herculis is situated in the Hertzsprung–Russell diagram.
σ Herculis star system properties
σ Herculis is a visual double star which can be observed only with the help of very large telescopes. The table below shows key information about the σ Herculis double sysyem: