Brachium - σ Librae (sigma Librae)

Altitude: 13.2° Azimuth: 179.1° Direction: South

Brachium, also designated as σ Librae (sigma Librae), is a variable giant star in the constellation of Libra.

Brachium visual magnitude is 3.29. Because of its moderate brightness, Brachium 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 Brachium:

Color of Brachium ⬤

Magnitude of Brachium 3.29

Class Giant

VISIBILITY RIGHT NOW

Brachium - σ Librae (sigma Librae) is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 13.2°
Azimuth: 179.1°
Direction: South

Celestial coordinates and finder chart of Brachium

Brachium is situated south of the celestial equator, as such, it is more easily visible from the southern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of Brachium are provided in the following table:

Right Ascension J2000 15h 04m 04s

Declination J2000 -25° 16’ 54”

Galactic Longitude 337.22°

Galactic Latitude 28.62°

Constellation Libra

The simplified sky map below shows the position of Brachium in the sky:

Finder chart Brachium - σ Librae (sigma Librae) star

Simplified finder chart for Brachium - σ Librae (sigma Librae).

Visibility of Brachium 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 Brachium - σ Librae (sigma Librae) 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: 115.3° RISE 11:38

Max altitude: 13.2° TRANSIT 15:12

Azimuth: 244.7° SET 18:45

Digitized Sky Survey image of Brachium

The image below is a photograph of Brachium 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 Brachium is -0.073 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 Brachium - σ Librae (sigma Librae) star

DSS2 image of Brachium. The red arrow shows the motion of Brachium during the next 10000 years (-12.17 arcmin in Right Ascension and -7.17 arcmin in declination);

Distance of Brachium from the Sun and relative movement

Brachium is distant 291.85 light years from the Sun and it is moving towards the Sun at the speed of 4 kilometers per second.

Distance (parsec) 89.53 pc

Distance (light year) 291.85 ly

Heliocentric radial velocity -4 km/s

Proper Motion RA -0.073 arcsec/year

Proper Motion Dec -0.043 arcsec/year

Spectral properties of Brachium

Brachium belongs to spectral class M3 and has a luminosity class of III corresponding to a giant star.

Absolute magnitude -1.47

Spectral Type M3III

Color Index (B-V) 1.7

Temperature of Brachium 3516K

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

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

Alternative designations of Brachium

Proper Name Brachium

Bayer designation σ Librae
(sigma Librae)

Flamsteed designation 20 Librae

Henry Draper Catalogue HD133216

SAO Catalogue SAO183139

Hipparcos Catalogue HIP73714

Durchmusterung Catalogue CD-2411834

FK5 Catalogue 556

General Catalogue of Variable Stars Sig Lib

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