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:

Color of σ Herculis ⬤

Magnitude of σ Herculis 4.2

Class Main-sequence

VISIBILITY RIGHT NOW σ Herculis (sigma Herculis) is above the horizon from Greenwich, United Kingdom edit_location_alt. Altitude: 9°.

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:

Right Ascension J2000 16h 34m 06s

Declination J2000 +42° 26’ 12”

Galactic Longitude 66.91°

Galactic Latitude 42.7°

Constellation Hercules

The simplified sky map below shows the position of σ Herculis in the sky:

Finder chart σ Herculis (sigma Herculis) star

Simplified finder chart for σ Herculis (sigma Herculis).

Visibility of σ Herculis from your location

Location: Greenwich, United Kingdom edit_location_alt
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
Timezone: Europe/London

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.

Image of σ Herculis (sigma Herculis) star

DSS2 image of σ Herculis. The red arrow shows the motion of σ Herculis during the next 10000 years (-1.83 arcmin in Right Ascension and 7.67 arcmin in declination);

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.

Distance (parsec) 92.68 pc

Distance (light year) 302.13 ly

Heliocentric radial velocity -11 km/s

Proper Motion RA -0.011 arcsec/year

Proper Motion Dec 0.046 arcsec/year

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.

Absolute magnitude -0.63

Spectral Type B9V

Color Index (B-V) -0.01

Temperature of σ Herculis 10252K

The red dot in the diagram below shows where σ Herculis is situated in the Hertzsprung–Russell diagram.

H-R diagram showing the position of σ Herculis. Attribution: Richard Powell / CC BY-SA

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:

Main star magnitude 4.2

Secondary star magnitude 7.2

Magnitude difference 3

Separation 0.1 arcsec

Alternative designations of σ Herculis

Bayer designation σ Herculis
(sigma Herculis)

Flamsteed designation 35 Herculis

Henry Draper Catalogue HD149630

SAO Catalogue SAO46161

Hipparcos Catalogue HIP81126

Durchmusterung Catalogue BD+42 2724

FK5 Catalogue 621

General Catalogue of Variable Stars 7837

In Evidence

Other stars in Hercules