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Alnitak - ζ Orionis (zeta Orionis)

Alnitak, also designated as ζ Orionis (zeta Orionis), is a variable and multiple supergiant star in the constellation of Orion.

Alnitak visual magnitude is 2.05, making it the 53th brightest star in the sky. Thanks to its high brightness, Alnitak is clearly visible when observed from locations with dark skyes, and should be also quite easily visible from light polluted areas.

The table below summarizes the key facts about Alnitak:

Color of Alnitak ⬤

Magnitude of Alnitak 2.05

Class Supergiant

VISIBILITY RIGHT NOW Alnitak - ζ Orionis (zeta Orionis) is above the horizon from Greenwich, United Kingdom [change]. Altitude: 17°.

Celestial coordinates and finder chart of Alnitak

Alnitak 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 Alnitak are provided in the following table:

Right Ascension J2000 05h 40m 45s

Declination J2000 -01° 56’ 34”

Galactic Longitude 206.45°

Galactic Latitude -16.59°

Constellation Orion

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

Finder chart Alnitak - ζ Orionis (zeta Orionis) star

Simplified finder chart for Alnitak - ζ Orionis (zeta Orionis).

Visibility of Alnitak from your location

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

Today's Alnitak - ζ Orionis (zeta Orionis) rise, transit and set times from Greenwich, United Kingdom [change] are the following (all times relative to the local timezone Europe/London):

Azimuth: 91.9° RISE 11:52

Max altitude: 36.6° TRANSIT 17:40

Azimuth: 268.1° SET 23:29

RIGHT NOW Alnitak - ζ Orionis (zeta Orionis) is above the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of Alnitak

The image below is a photograph of Alnitak 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 Alnitak is 0.003 arcsec per year in Right Ascension and -0.002 arcsec per year in Declination and the associated displacement for the next 100000 years is represented with the red arrow.

Image of Alnitak - ζ Orionis (zeta Orionis) star

DSS2 image of Alnitak. The red arrow shows the motion of Alnitak during the next 100000 years (5.00 arcmin in Right Ascension and -3.33 arcmin in declination);

Distance of Alnitak from the Sun and relative movement

Alnitak is distant 817.04 light years from the Sun and it is moving far from the Sun at the speed of 18 kilometers per second.

Distance (parsec) 250.63 pc

Distance (light year) 817.04 ly

Heliocentric radial velocity 18 km/s

Proper Motion RA 0.003 arcsec/year

Proper Motion Dec -0.002 arcsec/year

Spectral properties of Alnitak

Alnitak belongs to spectral class O9 and has a luminosity class of I corresponding to a supergiant star.

Absolute magnitude -4.95

Spectral Type O9I

Color Index (B-V) -0.21

Temperature of Alnitak 13831K

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

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

Alnitak star system properties

Alnitak is a visual double star which can be observed with the help of medium or large telescopes. The table below shows key information about the Alnitak double sysyem:

Main star magnitude 2.05

Secondary star magnitude 4.25

Magnitude difference 2.2

Separation 2.4 arcsec

Alternative designations of Alnitak

Proper Name Alnitak

Bayer designation ζ Orionis
(zeta Orionis)

Flamsteed designation 50 Orionis

Henry Draper Catalogue HD37742

SAO Catalogue SAO132444

Hipparcos Catalogue HIP26727

Durchmusterung Catalogue BD-02 1338

General Catalogue of Variable Stars 2553

Aitken Double Star Catalogue ADS4263

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