21 Hydrae

Altitude: 10.3° Azimuth: 115.4° Direction: East-South-East

21 Hydrae is a variable giant star in the constellation of Hydra.

21 Hydrae visual magnitude is 6.11. Because of its reltive faintness, 21 Hydrae 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 21 Hydrae:

Color of 21 Hydrae ⬤

Magnitude of 21 Hydrae 6.11

Class Giant

VISIBILITY RIGHT NOW

21 Hydrae is above the horizon from Greenwich, United Kingdom edit_location_alt.

Altitude: 10.3°
Azimuth: 115.4°
Direction: East-South-East

Celestial coordinates and finder chart of 21 Hydrae

21 Hydrae 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 21 Hydrae are provided in the following table:

Right Ascension J2000 09h 12m 25s

Declination J2000 -07° 06’ 34”

Galactic Longitude 237.55°

Galactic Latitude 26.95°

Constellation Hydra

The simplified sky map below shows the position of 21 Hydrae in the sky:

Simplified finder chart for 21 Hydrae.

Visibility of 21 Hydrae 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 21 Hydrae 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: 97.1° RISE 11:35

Max altitude: 31.4° TRANSIT 16:57

Azimuth: 262.9° SET 22:19

RIGHT NOW 21 Hydrae is above the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of 21 Hydrae

The image below is a photograph of 21 Hydrae 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 21 Hydrae is -0.016 arcsec per year in Right Ascension and 0.019 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

DSS2 image of 21 Hydrae. The red arrow shows the motion of 21 Hydrae during the next 10000 years (-2.67 arcmin in Right Ascension and 3.17 arcmin in declination);

Distance of 21 Hydrae from the Sun and relative movement

21 Hydrae is distant 269.42 light years from the Sun and it is moving towards the Sun at the speed of 4 kilometers per second.

Distance (parsec) 82.64 pc

Distance (light year) 269.42 ly

Heliocentric radial velocity -4 km/s

Proper Motion RA -0.016 arcsec/year

Proper Motion Dec 0.019 arcsec/year

Spectral properties of 21 Hydrae

21 Hydrae belongs to spectral class A3 and has a luminosity class of III corresponding to a giant star.

Absolute magnitude 1.52

Spectral Type A3III

Color Index (B-V) 0.22

Temperature of 21 Hydrae 8011K

The red dot in the diagram below shows where 21 Hydrae is situated in the Hertzsprung–Russell diagram.

H-R diagram showing the position of 21 Hydrae. Attribution: Richard Powell / CC BY-SA

Alternative designations of 21 Hydrae

Flamsteed designation 21 Hydrae

Henry Draper Catalogue HD79193

SAO Catalogue SAO136662

Hipparcos Catalogue HIP45184

Durchmusterung Catalogue BD-06 2845

General Catalogue of Variable Stars KW Hya

In Evidence

Other stars in Hydra