θ Ophiuchi (theta Ophiuchi)

θ Ophiuchi is a variable and double sub-giant star in the constellation of Ophiuchus.

θ Ophiuchi visual magnitude is 3.27. Because of its moderate brightness, θ Ophiuchi 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 θ Ophiuchi:

Color of θ Ophiuchi ⬤

Magnitude of θ Ophiuchi 3.27

Class Sub-giant

VISIBILITY RIGHT NOW θ Ophiuchi (theta Ophiuchi) is above the horizon from Greenwich, United Kingdom edit_location_alt. Altitude: 9°.

Celestial coordinates and finder chart of θ Ophiuchi

θ Ophiuchi 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 θ Ophiuchi are provided in the following table:

Right Ascension J2000 17h 22m 00s

Declination J2000 -24° 59’ 57”

Galactic Longitude 0.46°

Galactic Latitude 6.55°

Constellation Ophiuchus

The simplified sky map below shows the position of θ Ophiuchi in the sky:

Finder chart θ Ophiuchi (theta Ophiuchi) star

Simplified finder chart for θ Ophiuchi (theta Ophiuchi).

Visibility of θ Ophiuchi 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 θ Ophiuchi (theta Ophiuchi) 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: 115.0° RISE 22:05

Max altitude: 13.5° TRANSIT 1:44

Azimuth: 245.0° SET 5:20

RIGHT NOW θ Ophiuchi (theta Ophiuchi) is above the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of θ Ophiuchi

The image below is a photograph of θ Ophiuchi 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 θ Ophiuchi is -0.004 arcsec per year in Right Ascension and -0.02 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of θ Ophiuchi (theta Ophiuchi) star

DSS2 image of θ Ophiuchi. The red arrow shows the motion of θ Ophiuchi during the next 10000 years (-0.67 arcmin in Right Ascension and -3.33 arcmin in declination);

Distance of θ Ophiuchi from the Sun and relative movement

θ Ophiuchi is distant 563.04 light years from the Sun and it is moving towards the Sun at the speed of 2 kilometers per second.

Distance (parsec) 172.71 pc

Distance (light year) 563.04 ly

Heliocentric radial velocity -2 km/s

Proper Motion RA -0.004 arcsec/year

Proper Motion Dec -0.02 arcsec/year

Spectral properties of θ Ophiuchi

θ Ophiuchi belongs to spectral class B2 and has a luminosity class of IV corresponding to a sub-giant star.

Absolute magnitude -2.92

Spectral Type B2IV

Color Index (B-V) -0.22

Temperature of θ Ophiuchi 14087K

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

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

θ Ophiuchi star system properties

θ Ophiuchi 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 θ Ophiuchi double sysyem:

Main star magnitude 3.27

Secondary star magnitude 5.27

Magnitude difference 2

Separation 0 arcsec

Alternative designations of θ Ophiuchi

Bayer designation θ Ophiuchi
(theta Ophiuchi)

Flamsteed designation 42 Ophiuchi

Henry Draper Catalogue HD157056

SAO Catalogue SAO185320

Hipparcos Catalogue HIP84970

Durchmusterung Catalogue CD-2413292

FK5 Catalogue 644

General Catalogue of Variable Stars The Oph

In Evidence

Other stars in Ophiuchus