21 Orionis

Altitude: -24.5° Azimuth: 49.2° Direction: North-East

21 Orionis is a variable bright giant star in the constellation of Orion.

21 Orionis visual magnitude is 5.34. Because of its reltive faintness, 21 Orionis should be visible only from locations with dark skyes, while it is not visible at all from skyes affected by light pollution.

The table below summarizes the key facts about 21 Orionis:

Color of 21 Orionis ⬤

Magnitude of 21 Orionis 5.34

Class Bright giant

VISIBILITY RIGHT NOW

21 Orionis is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -24.5°
Azimuth: 49.2°
Direction: North-East

Celestial coordinates and finder chart of 21 Orionis

21 Orionis 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 21 Orionis are provided in the following table:

Right Ascension J2000 05h 19m 11s

Declination J2000 +02° 35’ 44”

Galactic Longitude 199.54°

Galactic Latitude -19.12°

Constellation Orion

The simplified sky map below shows the position of 21 Orionis in the sky:

Simplified finder chart for 21 Orionis.

Visibility of 21 Orionis 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 21 Orionis 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: 87.4° RISE 18:25

Max altitude: 41.1° TRANSIT 0:40

Azimuth: 272.6° SET 6:51

Digitized Sky Survey image of 21 Orionis

The image below is a photograph of 21 Orionis 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 21 Orionis is -0.017 arcsec per year in Right Ascension and -0.047 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

DSS2 image of 21 Orionis. The red arrow shows the motion of 21 Orionis during the next 10000 years (-2.83 arcmin in Right Ascension and -7.83 arcmin in declination);

Distance of 21 Orionis from the Sun and relative movement

21 Orionis is distant 197.94 light years from the Sun and it is moving far from the Sun at the speed of 11 kilometers per second.

Distance (parsec) 60.72 pc

Distance (light year) 197.94 ly

Heliocentric radial velocity 11 km/s

Proper Motion RA -0.017 arcsec/year

Proper Motion Dec -0.047 arcsec/year

Spectral properties of 21 Orionis

21 Orionis belongs to spectral class F5 and has a luminosity class of II corresponding to a bright giant star.

Absolute magnitude 1.42

Spectral Type F5II

Color Index (B-V) 0.41

Temperature of 21 Orionis 6827K

The red dot in the diagram below shows where 21 Orionis is situated in the Hertzsprung–Russell diagram.

H-R diagram showing the position of 21 Orionis. Attribution: Richard Powell / CC BY-SA

Alternative designations of 21 Orionis

Flamsteed designation 21 Orionis

Henry Draper Catalogue HD34658

SAO Catalogue SAO112624

Hipparcos Catalogue HIP24817

Durchmusterung Catalogue BD+02 916

General Catalogue of Variable Stars 1922

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In Evidence

Other stars in Orion