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V Hydrae - HIP53085

V Hydrae is a pulsating very luminous supergiant star that can be located in the constellation of Hydra. The star can not be seen by the naked eye, you need a telescope to see it.

HIP53085 is the reference name for the star in the Hipparcos Star Catalogue.

V Hydrae has alternative name(s), V_Hya.

Location of V Hydrae

The location of the star in the galaxy is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For V Hydrae, the location is 10h 51m 37.26 and -21d15`00.3 .

Proper Motion of V Hydrae

All stars like planets orbit round a central spot, in the case of planets, its the central star such as the Sun. In the case of a star, its the galactic centre. The constellations that we see today will be different than they were 50,000 years ago or 50,000 years from now. Proper Motion details the movements of these stars and are measured in milliarcseconds. The star is moving 2.29 ± 0.66 miliarcseconds/year towards the north and -11.02 ± 1.41 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Temperature, Radius) of V Hydrae

V Hydrae has a spectral type of C9I. This means the star is a supergiant star. The star has a B-V Colour Index of 2.6 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 2 Kelvin.

V Hydrae Radius has been calculated as being 1,936,029,367.73 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,347,089,234,065,873.77.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 215211319.99. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

V Hydrae Apparent and Absolute Magnitudes

V Hydrae has an apparent magnitude of 7.00 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, you would get an absolute magnitude of -6.98 If you used the 2007 Parallax value, you would get an absolute magnitude of -2.21. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Distance to V Hydrae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 0.16 which gave the calculated distance to V Hydrae as 20385.21 light years away from Earth or 6250 parsecs. It would take a spaceship travelling at the speed of light, 20385.21 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

In 2007, Hipparcos data was revised with a new parallax of 1.44 which put V Hydrae at a distance of 2265.02 light years or 694.44 parsecs. It should not be taken as though the star is moving closer or further away from us. It is purely that the distance was recalculated.

Variable Type of V Hydrae

The star is a pulsating Slow Irregular variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. V Hydrae brightness ranges from a magnitude of 8.000 to a magnitude of 6.000 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 2.0 days (variability).

Source of Information

The source of the information if it has a Hip I.D. is from Simbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was a E.S.A. satellite operation launched in 1989 for four years. The items in red are values that I've calculated so they could well be wrong. Information regarding Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

V Hydrae Facts

Alternative Names

Traditional/Proper NameV Hydrae
Short NameV Hya
Hipparcos Library I.D.53085
Bonner DurchmusterungBDD-20 3283

Visual Facts

Star Typesupergiant star
Absolute Magnitude-6.98 / -2.21
Visual / Apparent Magnitude7.00
Naked Eye VisibleRequires a 7x50 Binoculars - Ref: Wiki
Right Ascension (R.A.)10h 51m 37.26
Declination (Dec.)-21d15`00.3
Galactic Latitude33.60 degrees
Galactic Longitude268.96 degrees
1997 Distance from Earth0.16 Parallax (milliarcseconds)
 20385.21 Light Years
 6250 Parsecs
2007 Revised Distance from Earth1.44 Parallax (milliarcseconds)
 2265.02 Light Years
 694.44 Parsecs
Proper Motion Dec.2.29 ± 0.66 milliarcseconds/year
Proper Motion RA.-11.02 ± 1.41 milliarcseconds/year
B-V Index2.60
Radial Velocity-14.80 ± 1.70 km/s
Spectral TypeC9I

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSlow Irregular
Mean Variability Period in Days2.000
Variable Magnitude Range (Brighter - Dimmer)6.000 - 8.000

Estimated Facts

Calculated Effective Temperature2 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.


Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
-20 3283.0A6.00000-24.00000N6
B11.000001903

Location of V Hydrae in Hydra


V Hydrae Location in Hydra

The map was generated using Night Vision, an awesome free application by Brian Simpson.


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