Universe Guide

HomeFactsConstellationsVela

HR 3831 - HD83368 - HIP47145

HR 3831 is a blue to white rotating star that can be located in the constellation of Vela. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

HIP47145 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD83368.

HR 3831 has alternative name(s), IM_Vel.

Location of HR 3831

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 HR 3831, the location is 09h 36m 25.41 and -48d45`04.2 .

Proper Motion of HR 3831

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 -8.63 ± 0.36 miliarcseconds/year towards the north and -7.33 ± 0.47 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of HR 3831

HR 3831 has a spectral type of F0p. This means the star is a blue to white star. The star is 7396.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24123.0409222400000000s. The star has a B-V Colour Index of 0.27 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,943 Kelvin.

HR 3831 Radius has been calculated as being 2.72 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,889,187.41.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 2.64. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

HR 3831 Apparent and Absolute Magnitudes

HR 3831 has an apparent magnitude of 6.18 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 1.88 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.94. 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 HR 3831

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 13.80 which gave the calculated distance to HR 3831 as 236.35 light years away from Earth or 72.46 parsecs. It would take a spaceship travelling at the speed of light, 236.35 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 14.16 which put HR 3831 at a distance of 230.34 light years or 70.62 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 7,396.00 Parsecs or 24,123.04 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 HR 3831

The star is a rotating Alpha2 Canum Venaticorum 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. HR 3831 brightness ranges from a magnitude of 6.000 to a magnitude of 6.000 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 3.0 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.

HR 3831 Facts

Alternative Names

Traditional/Proper NameHR 3831
Short NameIM Vel
Hipparcos Library I.D.47145
Henry Draper Designation83368

Visual Facts

Star Type star
Absolute Magnitude1.88 / 1.94
Visual / Apparent Magnitude6.18
Naked Eye VisibleYes - Ref: Wiki
Right Ascension (R.A.)09h 36m 25.41
Declination (Dec.)-48d45`04.2
Galactic Latitude2.52 degrees
Galactic Longitude273.18 degrees
1997 Distance from Earth13.80 Parallax (milliarcseconds)
 236.35 Light Years
 72.46 Parsecs
2007 Revised Distance from Earth14.16 Parallax (milliarcseconds)
 230.34 Light Years
 70.62 Parsecs
Galacto-Centric Distance24,123.04 Light Years / 7,396.00 Parsecs
Proper Motion Dec.-8.63 ± 0.36 milliarcseconds/year
Proper Motion RA.-7.33 ± 0.47 milliarcseconds/year
B-V Index0.27
Radial Velocity-2.80 ± 0.80 km/s
Spectral TypeF0p
Colour(F) blue to white

Variable Star Details

Variable Star ClassRotating
Variable Star TypeAlpha2 Canum Venaticorum
Mean Variability Period in Days3.000

Estimated Facts

Calculated Effective Temperature6,943 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
83368-48 4831.2A6.60000-8.00000-22.00000F0Yellow/White
B9.000001948

Add a Comment


Name:
Email: (Optional)
Comment: