31 Cygni

31 Cygni is a variable and multiple bright giant star in the constellation of Cygnus.

31 Cygni visual magnitude is 3.79. Because of its moderate brightness, 31 Cygni 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 31 Cygni:

Color of 31 Cygni ⬤

Magnitude of 31 Cygni 3.79

Class Bright giant

VISIBILITY RIGHT NOW 31 Cygni is above the horizon from Greenwich, United Kingdom edit_location_alt. Altitude: 69°.

Celestial coordinates and finder chart of 31 Cygni

31 Cygni is situated north of the celestial equator, as such, it is more easily visible from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of 31 Cygni are provided in the following table:

Right Ascension J2000 20h 13m 37s

Declination J2000 +46° 44’ 29”

Galactic Longitude 82.68°

Galactic Latitude 6.78°

Constellation Cygnus

The simplified sky map below shows the position of 31 Cygni in the sky:

Simplified finder chart for 31 Cygni.

Visibility of 31 Cygni from your location

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

31 Cygni is circumpolar and transits at 03:44 UTC (altitude: 85.3°)

Digitized Sky Survey image of 31 Cygni

The image below is a photograph of 31 Cygni 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 31 Cygni is 0.004 arcsec per year in Right Ascension and 0.003 arcsec per year in Declination and the associated displacement for the next 100000 years is represented with the red arrow.

DSS2 image of 31 Cygni. The red arrow shows the motion of 31 Cygni during the next 100000 years (6.67 arcmin in Right Ascension and 5.00 arcmin in declination);

Distance of 31 Cygni from the Sun and relative movement

31 Cygni is distant 1,352.70 light years from the Sun and it is moving towards the Sun at the speed of 8 kilometers per second.

Distance (parsec) 414.94 pc

Distance (light year) 1,352.70 ly

Heliocentric radial velocity -8 km/s

Proper Motion RA 0.004 arcsec/year

Proper Motion Dec 0.003 arcsec/year

Spectral properties of 31 Cygni

31 Cygni belongs to spectral class K2 and has a luminosity class of II corresponding to a bright giant star.

Absolute magnitude -4.30

Spectral Type K2II

Color Index (B-V) 1.28

Temperature of 31 Cygni 4158K

The red dot in the diagram below shows where 31 Cygni is situated in the Hertzsprung–Russell diagram.

H-R diagram showing the position of 31 Cygni. Attribution: Richard Powell / CC BY-SA

31 Cygni star system properties

31 Cygni is a visual double star which can be observed with binoculars or small telescopes. The table below shows key information about the 31 Cygni double sysyem:

Main star magnitude 3.79

Secondary star magnitude 4.79

Magnitude difference 1

Separation 337.5 arcsec

Alternative designations of 31 Cygni

Flamsteed designation 31 Cygni

Henry Draper Catalogue HD192577

SAO Catalogue SAO49337

Hipparcos Catalogue HIP99675

Durchmusterung Catalogue BD+46 2882

FK5 Catalogue 757

General Catalogue of Variable Stars V695 Cyg

Aitken Double Star Catalogue ADS13554

In Evidence

Other stars in Cygnus