Your Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 6:59  
clear_day Transit: 12:48  
SunsetSet: 18:36 south
sunny DaytimeWhat's Visible Now
All Constellations » Ophiuchus » 

HR6639

Altitude: -8.6°   Azimuth: 75.8°   Direction: East-North-East

HR6639 is a hypergiant star in the constellation of Ophiuchus.

HR6639 visual magnitude is 6.47. Because of its reltive faintness, HR6639 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 HR6639:

6.47
Hypergiant

HR6639 is below the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: -8.6°
Azimuth: 75.8°
Direction: East-North-East

Celestial coordinates and finder chart of HR6639

HR6639 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 HR6639 are provided in the following table:

17h 49m 18s
+01° 57’ 39”
27.5°
14.7°
Ophiuchus

The simplified sky map below shows the position of HR6639 in the sky:

Finder chart HR6639 star
Simplified finder chart for HR6639.

Visibility of HR6639 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 HR6639 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: 88.0°
Max altitude: 40.5°
Azimuth: 272.0°

Digitized Sky Survey image of HR6639

The image below is a photograph of HR6639 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 HR6639 is -0.025 arcsec per year in Right Ascension and 0.065 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

Image of HR6639 star
DSS2 image of HR6639. The red arrow shows the motion of HR6639 during the next 10000 years (-4.17 arcmin in Right Ascension and 10.83 arcmin in declination);

Distance of HR6639 from the Sun and relative movement

HR6639 is distant 341.72 light years from the Sun and it is moving towards the Sun at the speed of 58 kilometers per second.

104.82 pc
341.72 ly
-58 km/s
-0.025 arcsec/year
0.065 arcsec/year

Spectral properties of HR6639

HR6639 belongs to spectral class K0 and has a luminosity class of III corresponding to a hypergiant star.

1.37
K0III
4232K

The red dot in the diagram below shows where HR6639 is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of HR6639. Attribution: Richard Powell / CC BY-SA

Alternative designations of HR6639

SAO122787
SAO122787