γ Herculis (gamma Herculis)

γ Herculis is a variable and multiple giant star in the constellation of Hercules.

γ Herculis visual magnitude is 3.75. Because of its moderate brightness, γ 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 γ Herculis:

Color of γ Herculis ⬤

Magnitude of γ Herculis 3.75

Class Giant

VISIBILITY RIGHT NOW γ Herculis (gamma Herculis) is above the horizon from Greenwich, United Kingdom edit_location_alt. Altitude: 55°.

Celestial coordinates and finder chart of γ Herculis

γ Herculis is situated close to the celestial equator, as such, it is at least partly visible from both hemispheres in certain times of the year. Celestial coordinates for the J2000 equinox as well as galactic coordinates of γ Herculis are provided in the following table:

Right Ascension J2000 16h 21m 55s

Declination J2000 +19° 09’ 11”

Galactic Longitude 35.26°

Galactic Latitude 41.3°

Constellation Hercules

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

Finder chart γ Herculis (gamma Herculis) star

Simplified finder chart for γ Herculis (gamma Herculis).

Visibility of γ Herculis from your location

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

Today's γ Herculis (gamma Herculis) rise, transit and set times from Greenwich, United Kingdom edit_location_alt are the following (all times relative to the local timezone Europe/London):

Azimuth: 70.8° RISE 16:56

Max altitude: 57.7° TRANSIT 0:37

Azimuth: 289.2° SET 8:22

RIGHT NOW γ Herculis (gamma Herculis) is above the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of γ Herculis

The image below is a photograph of γ 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 γ Herculis is -0.047 arcsec per year in Right Ascension and 0.043 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of γ Herculis (gamma Herculis) star

DSS2 image of γ Herculis. The red arrow shows the motion of γ Herculis during the next 10000 years (-7.83 arcmin in Right Ascension and 7.17 arcmin in declination);

Distance of γ Herculis from the Sun and relative movement

γ Herculis is distant 195.33 light years from the Sun and it is moving towards the Sun at the speed of 35 kilometers per second.

Distance (parsec) 59.92 pc

Distance (light year) 195.33 ly

Heliocentric radial velocity -35 km/s

Proper Motion RA -0.047 arcsec/year

Proper Motion Dec 0.043 arcsec/year

Spectral properties of γ Herculis

γ Herculis belongs to spectral class A9 and has a luminosity class of III corresponding to a giant star.

Absolute magnitude -0.14

Spectral Type A9III

Color Index (B-V) 0.27

Temperature of γ Herculis 7658K

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

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

γ Herculis star system properties

γ 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 γ Herculis double sysyem:

Main star magnitude 3.75

Secondary star magnitude 10.15

Magnitude difference 6.4

Separation 41.6 arcsec

Alternative designations of γ Herculis

Bayer designation γ Herculis
(gamma Herculis)

Flamsteed designation 20 Herculis

Henry Draper Catalogue HD147547

SAO Catalogue SAO102107

Hipparcos Catalogue HIP80170

Durchmusterung Catalogue BD+19 3086

FK5 Catalogue 609

General Catalogue of Variable Stars 7667

Aitken Double Star Catalogue ADS10022

In Evidence

Other stars in Hercules