η Orionis (eta Orionis)

η Orionis is a variable and multiple main-sequence star in the constellation of Orion.

η Orionis visual magnitude is 3.36. Because of its moderate brightness, η Orionis 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 η Orionis:

Color of η Orionis ⬤

Magnitude of η Orionis 3.36

Class Main-sequence

VISIBILITY RIGHT NOW η Orionis (eta Orionis) is below the horizon from Greenwich, United Kingdom [change].

Celestial coordinates and finder chart of η Orionis

η 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 η Orionis are provided in the following table:

Right Ascension J2000 05h 24m 28s

Declination J2000 -02° 23’ 48”

Galactic Longitude 204.87°

Galactic Latitude -20.39°

Constellation Orion

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

Finder chart η Orionis (eta Orionis) star

Simplified finder chart for η Orionis (eta Orionis).

Visibility of η Orionis from your location

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

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

Azimuth: 92.4° RISE 11:42

Max altitude: 36.1° TRANSIT 17:28

Azimuth: 267.6° SET 23:14

RIGHT NOW η Orionis (eta Orionis) is below the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of η Orionis

The image below is a photograph of η 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 η Orionis is 0.002 arcsec per year in Right Ascension and 0 arcsec per year in Declination and the associated displacement for the next 100000 years is represented with the red arrow.

DSS2 image of η Orionis. The red arrow shows the motion of η Orionis during the next 100000 years (3.33 arcmin in Right Ascension and 0.00 arcmin in declination);

Distance of η Orionis from the Sun and relative movement

η Orionis is distant 900.55 light years from the Sun and it is moving far from the Sun at the speed of 20 kilometers per second.

Distance (parsec) 276.24 pc

Distance (light year) 900.55 ly

Heliocentric radial velocity 20 km/s

Proper Motion RA 0.002 arcsec/year

Spectral properties of η Orionis

η Orionis belongs to spectral class B1 and has a luminosity class of V corresponding to a main-sequence star.

Absolute magnitude -3.85

Spectral Type B1V

Color Index (B-V) -0.17

Temperature of η Orionis 12902K

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

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

η Orionis star system properties

η Orionis 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 η Orionis double sysyem:

Main star magnitude 3.36

Secondary star magnitude 4.76

Magnitude difference 1.4

Separation 1.5 arcsec

Alternative designations of η Orionis

Bayer designation η Orionis
(eta Orionis)

Flamsteed designation 28 Orionis

Henry Draper Catalogue HD35411

SAO Catalogue SAO132071

Hipparcos Catalogue HIP25281

Durchmusterung Catalogue BD-02 1235

General Catalogue of Variable Stars Eta Ori

Aitken Double Star Catalogue ADS4002

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Other stars in Orion