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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
north SunriseRise: 7:52  
clear_day Transit: 11:51  
SunsetSet: 15:49 south
sleep NighttimeWhat's Visible Now?
All Constellations » Ursa Major » 


Altitude: 45.7°   Azimuth: 27.5°   Direction: North-North-East

HR4021 is a variable and multiple star in the constellation of Ursa Major.

HR4021 visual magnitude is 6.66. Because of its reltive faintness, HR4021 should be visible only from locations with dark skyes, while it is not visible at all from skyes affected by light pollution.

The table below summarizes the key facts about HR4021:


HR4021 is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 45.7°
Azimuth: 27.5°
Direction: North-North-East

Celestial coordinates and finder chart of HR4021

HR4021 is situated close to the northern celestial pole and, as such, it is visible for most part of the year from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of HR4021 are provided in the following table:

10h 17m 50s
+71° 03’ 38”
Ursa Major

The simplified sky map below shows the position of HR4021 in the sky:

Finder chart HR4021 star
Simplified finder chart for HR4021.

Visibility of HR4021 from your location

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

HR4021 is circumpolar and transits at 05:03 UTC (altitude: 70.4°)

Digitized Sky Survey image of HR4021

The image below is a photograph of HR4021 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 HR4021 is -0.031 arcsec per year in Right Ascension and -0.048 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of HR4021 star
DSS2 image of HR4021. The red arrow shows the motion of HR4021 during the next 10000 years (-5.17 arcmin in Right Ascension and -8.00 arcmin in declination);

Distance of HR4021 from the Sun and relative movement

HR4021 is distant 304.67 light years from the Sun and it is moving far from the Sun at the speed of 11 kilometers per second.

93.46 pc
304.67 ly
11 km/s
-0.031 arcsec/year
-0.048 arcsec/year

Spectral properties of HR4021

HR4021 belongs to spectral class A7


The red dot in the diagram below shows where HR4021 is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of HR4021. Attribution: Richard Powell / CC BY-SA

HR4021 star system properties

HR4021 is a visual double star which can be observed with the help of small or medium telescopes. The table below shows key information about the HR4021 double sysyem:

16.6 arcsec

Alternative designations of HR4021