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V420 Puppis - HD67698 - HIP39834

V420 Puppis is a blue eruptive subgiant star that can be located in the constellation of Puppis. The star can not be seen by the naked eye, you need a telescope to see it.

HIP39834 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD67698.

V420 Puppis has alternative name(s), V420_Pup.

Location of V420 Puppis

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 V420 Puppis, the location is 08h 08m 19.36 and -23d37`04.1 .

Proper Motion of V420 Puppis

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 2.86 ± 0.22 miliarcseconds/year towards the north and -8.78 ± 0.41 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of V420 Puppis

V420 Puppis has a spectral type of B3III/IV. This means the star is a blue subgiant star. The star is 7560.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24657.9488064000000000s. The star has a B-V Colour Index of -0.07 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 10,845 Kelvin.

V420 Puppis Radius has been calculated as being 5.13 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 3,572,258.31.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 4.47. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

V420 Puppis Apparent and Absolute Magnitudes

V420 Puppis has an apparent magnitude of 6.56 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 -1.44 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.14. 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 V420 Puppis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 2.51 which gave the calculated distance to V420 Puppis as 1299.46 light years away from Earth or 398.41 parsecs. It would take a spaceship travelling at the speed of light, 1299.46 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 2.89 which put V420 Puppis at a distance of 1128.59 light years or 346.02 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.

The star's Galacto-Centric Distance is 7,560.00 Parsecs or 24,657.95 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Variable Type of V420 Puppis

The star is a eruptive Gamma Cassiopeiae 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. V420 Puppis brightness ranges from a magnitude of 7.000 to a magnitude of 6.000 over its variable period. The smaller the magnitude, the brighter the star.

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.

V420 Puppis Facts

Alternative Names

Traditional/Proper NameV420 Puppis
Short NameV420 Pup
Hipparcos Library I.D.39834
Henry Draper Designation67698

Visual Facts

Star Typesubgiant star
Absolute Magnitude-1.44 / -1.14
Visual / Apparent Magnitude6.56
Naked Eye VisibleRequires a 7x50 Binoculars - Ref: Wiki
Right Ascension (R.A.)08h 08m 19.36
Declination (Dec.)-23d37`04.1
Galactic Latitude4.92 degrees
Galactic Longitude242.66 degrees
1997 Distance from Earth2.51 Parallax (milliarcseconds)
 1299.46 Light Years
 398.41 Parsecs
2007 Revised Distance from Earth2.89 Parallax (milliarcseconds)
 1128.59 Light Years
 346.02 Parsecs
Galacto-Centric Distance24,657.95 Light Years / 7,560.00 Parsecs
Proper Motion Dec.2.86 ± 0.22 milliarcseconds/year
Proper Motion RA.-8.78 ± 0.41 milliarcseconds/year
B-V Index-0.07
Radial Velocity41.00 ± 5.60 km/s
Spectral TypeB3III/IV
Colour(B) blue

Variable Star Details

Variable Star ClassEruptive
Variable Star TypeGamma Cassiopeiae
Variable Magnitude Range (Brighter - Dimmer)6.000 - 7.000

Estimated Facts

Calculated Effective Temperature10,845 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
67698-23 6846.2A6.60000-13.000003.00000B5Blue/White
B14.000001926

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