Alnair - α Gruis (alpha Gruis)

Below the horizon. Rise: 0:18 | Tran: 4:00 | Set: 7:43

Alt: -68.10° Az: 154.44° Direction: South-South-East

Alnair, also designated as α Gruis (alpha Gruis), is a variable and double sub-giant star of spectral class B7 in the constellation of Grus.

Alnair visual magnitude is 1.74, making it the 30th brightest star in the sky. Because of its brightness, Alnair is clearly visible to the naked eye when observed from locations with dark skies, and should be also quite easily visible from light polluted areas.

Image of Alnair - α Gruis (alpha Gruis) star

DSS2 image of Alnair. The red arrow shows the motion of Alnair during the next 1000 years (2.15 arcmin in Right Ascension and -2.52 arcmin in declination);

Celestial Coordinates

Apparent

Right Ascension 22h 09m 49s

Declination -46° 50’ 07”

Hour Angle 12h 54m 25s

Sidereal Time 11h 04m 14s

J2000

Right Ascension 22h 08m 13s

Declination -46° 57’ 39”

Galactic Coordinates

Galactic Longitude 350°

Galactic Latitude -52.47°

Finder Chart

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Finder chart for Alnair - α Gruis (alpha Gruis).

Magnitude, Color, Spectral Class

Color ⬤

Magnitude 1.74

Class Sub-giant

Absolute magnitude -0.72

Spectral Type B7IV

Color Index (B-V) -0.13

Temperature 12103K

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

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

Star System Properties

Alnair 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 Alnair double sysyem:

Main star magnitude 1.74

Secondary star magnitude 11.84

Magnitude difference 10.1

Separation 28.4 arcsec

Distance, Radial Speed, Proper Motion

Alnair is distant 101.37 light years from the Sun and it is moving far from the Sun at the speed of 12 kilometers per second.

Distance (parsec) 31.09

Distance (light year) 101.37

Radial Speed 12 km/s

Proper Motion RA 0.129 arcsec/y

Proper Motion Dec -0.151"/y

Alternative Designations

Proper Name Alnair

Bayer designation α Gruis
(alpha Gruis)

Henry Draper Catalogue HD209952

SAO Catalogue SAO230992

Hipparcos Catalogue HIP109268

Durchmusterung Catalogue CD-4714063

Gliese Catalogue Gl 848.2

FK5 Catalogue 829

General Catalogue of Variable Stars 14040

Visibility from Your Location

Today's Alnair - α Gruis (alpha Gruis) rise, transit and set times from Tongren, China are the following (all times relative to the local timezone Asia/Shanghai):

Azimuth: 136.8° RISE 0:18

Max altitude: 15.4° TRANSIT 4:00

Azimuth: 223.2° SET 7:43

Name:	Tongren, China
Latitude:	27° 43' 1.9" N
Longitude:	109° 11' 6.0" E
Timezone:	Asia/Shanghai

Set Location

Other stars in Grus