ρ Hydrae (rho Hydrae)

ρ Hydrae is a double hypergiant star in the constellation of Hydra.

ρ Hydrae visual magnitude is 4.36. Because of its moderate brightness, ρ Hydrae should be easily visible from locations with dark skyes, while it can be barely visible, or not visible at all, from skyes affected by light pollution.

The table below summarizes the key facts about ρ Hydrae:

Color of ρ Hydrae ⬤

Magnitude of ρ Hydrae 4.36

Class Hypergiant

VISIBILITY RIGHT NOW ρ Hydrae (rho Hydrae) is above the horizon from Greenwich, United Kingdom [change]. Altitude: 37°.

Celestial coordinates and finder chart of ρ Hydrae

ρ 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 ρ Hydrae are provided in the following table:

Right Ascension J2000 08h 48m 25s

Declination J2000 +05° 50’ 16”

Galactic Longitude 221.52°

Galactic Latitude 28.62°

Constellation Hydra

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

Simplified finder chart for ρ Hydrae (rho Hydrae).

Visibility of ρ Hydrae from your location

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

Today's ρ Hydrae (rho Hydrae) rise, transit and set times from Greenwich, United Kingdom [change] are the following (all times relative to the local timezone Europe/London):

Azimuth: 84.2° RISE 14:20

Max altitude: 44.4° TRANSIT 20:48

Azimuth: 275.8° SET 3:19

RIGHT NOW ρ Hydrae (rho Hydrae) is above the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of ρ Hydrae

The image below is a photograph of ρ 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 ρ Hydrae is -0.017 arcsec per year in Right Ascension and -0.034 arcsec per year in Declination and the associated displacement for the next 10000 years is represented with the red arrow.

DSS2 image of ρ Hydrae. The red arrow shows the motion of ρ Hydrae during the next 10000 years (-2.83 arcmin in Right Ascension and -5.67 arcmin in declination);

Distance of ρ Hydrae from the Sun and relative movement

ρ Hydrae is distant 337.13 light years from the Sun and it is moving far from the Sun at the speed of 33 kilometers per second.

Distance (parsec) 103.41 pc

Distance (light year) 337.13 ly

Heliocentric radial velocity 33 km/s

Proper Motion RA -0.017 arcsec/year

Proper Motion Dec -0.034 arcsec/year

Spectral properties of ρ Hydrae

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

Absolute magnitude -0.71

Spectral Type A0V

Color Index (B-V) -0.04

Temperature of ρ Hydrae 10653K

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

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

ρ Hydrae star system properties

ρ Hydrae is a visual double star which can be observed only with the help of very large telescopes. The table below shows key information about the ρ Hydrae double sysyem:

Main star magnitude 4.36

Secondary star magnitude 13.06

Magnitude difference 8.7

Separation 12.4 arcsec

Alternative designations of ρ Hydrae

Bayer designation ρ Hydrae
(rho Hydrae)

Flamsteed designation 13 Hydrae

Henry Draper Catalogue HD75137

SAO Catalogue SAO117146

Hipparcos Catalogue HIP43234

Durchmusterung Catalogue BD+06 2040

Aitken Double Star Catalogue ADS7006

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