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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: 7:50  
clear_day Transit: 11:50  
SunsetSet: 15:49 south
sleep NighttimeWhat's Visible Now?
All Constellations » Hydra » 


Altitude: -70.6°   Azimuth: 28.7°   Direction: North-North-East

HR4651 is a double hypergiant star in the constellation of Hydra.

HR4651 visual magnitude is 6.33. Because of its reltive faintness, HR4651 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 HR4651:


HR4651 is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -70.6°
Azimuth: 28.7°
Direction: North-North-East

Celestial coordinates and finder chart of HR4651

HR4651 is situated south of the celestial equator, as such, it is more easily visible from the southern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of HR4651 are provided in the following table:

12h 13m 36s
-33° 47’ 34”

The simplified sky map below shows the position of HR4651 in the sky:

Finder chart HR4651 star
Simplified finder chart for HR4651.

Visibility of HR4651 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 HR4651 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: 123.8°
Max altitude: 4.7°
Azimuth: 236.2°

Digitized Sky Survey image of HR4651

The image below is a photograph of HR4651 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 HR4651 is -0.006 arcsec per year in Right Ascension and -0.011 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of HR4651 star
DSS2 image of HR4651. The red arrow shows the motion of HR4651 during the next 10000 years (-1.00 arcmin in Right Ascension and -1.83 arcmin in declination);

Distance of HR4651 from the Sun and relative movement

HR4651 is distant 405.98 light years from the Sun and it is moving towards the Sun at the speed of 11 kilometers per second.

124.53 pc
405.98 ly
-11 km/s
-0.006 arcsec/year
-0.011 arcsec/year

Spectral properties of HR4651

HR4651 belongs to spectral class A0 and has a luminosity class of V corresponding to a hypergiant star.


The red dot in the diagram below shows where HR4651 is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of HR4651. Attribution: Richard Powell / CC BY-SA

HR4651 star system properties

HR4651 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 HR4651 double sysyem:

1.6 arcsec

Alternative designations of HR4651