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A Complete Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
SunriseRise: 5:51  
clear_day Transit: 12:57  
SunsetSet: 20:04
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All Constellations » Boötes » 

40 Boötis

Altitude: 23.7°   Azimuth: 56.1°   Direction: North-East

40 Boötis is a hypergiant star in the constellation of Boötes.

40 Boötis visual magnitude is 5.64. Because of its reltive faintness, 40 Boötis should be visible only from locations with dark skies, while it is not visible at all from skies affected by light pollution.

The proper motion of 40 Boötis is -0.032 arcsec per year in Right Ascension and 0.042 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of 40 Boötis star
DSS2 image of 40 Boötis. The red arrow shows the motion of 40 Boötis during the next 10000 years (-5.33 arcmin in Right Ascension and 7.00 arcmin in declination);

Key facts about 40 Boötis


40 Boötis is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 23.7°
Azimuth: 56.1°
Direction: North-East

Celestial coordinates and finder chart of 40 Boötis

40 Boötis 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 40 Boötis are provided in the following table:

14h 59m 36s
+39° 15’ 55”

The simplified sky map below shows the position of 40 Boötis in the sky:

Finder chart 40 Boötis star
Simplified finder chart for 40 Boötis.

Visibility of 40 Boötis from your location

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

40 Boötis is circumpolar and transits at 01:01 UTC (altitude: 77.8°)

Distance of 40 Boötis from the Sun and relative movement

40 Boötis is distant 164.40 light years from the Sun and it is moving far from the Sun at the speed of 12 kilometers per second.

50.43 pc
164.40 ly
12 km/s
-0.032 arcsec/year
0.042 arcsec/year

Spectral properties of 40 Boötis

40 Boötis belongs to spectral class F0 and has a luminosity class of IV corresponding to a hypergiant star.


The red dot in the diagram below shows where 40 Boötis is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of 40 Boötis. Attribution: Richard Powell / CC BY-SA

Alternative designations of 40 Boötis