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Chalawan, 47 Ursae Majoris, HD95128, HIP53721, HR4277

Chalawan is a white to yellow main sequence dwarf star that can be located in the constellation of UrsaMajor. Chalawan is the brightest star in Ursa Major based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it. The star has an estimated age of 6.80 Billion of Years but could be as young as 4.90 to 8.10 according to Hipparcos.

The Id of the star in the Yale Bright Star Catalogue is HR4277. HIP53721 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD95128. The Gliese ID of the star is Gliese GL407. The star was part of the original catalogue devised by German Astronomer Wilheim Gliese of stars located within 20 parsecs of Earth. Ref : Star Names. Chalawan has at least 3 Extrasolar Planets believed to be in orbit around the star.

Location of Chalawan

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 Chalawan, the location is 10h 59m 28.22 and +40d25`48.4 .

Proper Motion of Chalawan

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 54.64 ± 0.17 miliarcseconds/year towards the north and -317.01 ± 0.25 miliarcseconds/year east if we saw them in the horizon.

Chalawan Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 1.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Age, Mass, Radius) of Chalawan

Chalawan has a spectral type of G0V. This means the star is a white to yellow main sequence dwarf star. The star is 7406.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24155.6572566400000000s. The star has a B-V Colour Index of 0.62 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,824 Kelvin.

Chalawan Radius has been calculated as being 1.27 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 884,917.90.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.27. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's solar mass is 1.03 times that of the Sun's. The Sun's Mass is 1,989,100,000,000,000,000,000 billion kg. which to calculate using this website is too large. To give idea of size, the Sun is 99.86% the mass of the solar system.

The star's metallicity is 0.000000, this value is the fractional amount of the star that is not Hydrogen (X) or Helium (Y). An older star would have a high metallicity whereas a new star would have a lower one.

The stars age according to Hipparcos data files put the star at an age of about 6.80 Billion years old but could be between 4.90 and 8.10 Billion years old. In comparison, the Sun's age is about 4.6 Billion Years Old.

Chalawan Apparent and Absolute Magnitudes

Chalawan has an apparent magnitude of 5.03 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 4.29 If you used the 2007 Parallax value, you would get an absolute magnitude of 4.29. 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 Chalawan

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 71.04 which gave the calculated distance to Chalawan as 45.91 light years away from Earth or 14.08 parsecs. It would take a spaceship travelling at the speed of light, 45.91 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 71.11 which put Chalawan at a distance of 45.87 light years or 14.06 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 7,406.00 Parsecs or 24,155.66 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

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.

Chalawan Facts

Alternative Names

Traditional/Proper NameChalawan
Flamsteed Name47 Ursae Majoris
Flamsteed Short Name47 UMa
Hipparcos Library I.D.53721
Yale Bright Star Catalogue (HR) Id4277
Bonner DurchmusterungBD+41 2147
Gliese ID407
Henry Draper Designation95128

Visual Facts

Star Typemain sequence dwarf star
Age6.80 Billion Years Old
Age Range4.90 - 8.10 Billion Years Old
Absolute Magnitude4.29 / 4.29
Visual / Apparent Magnitude5.03
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)10h 59m 28.22
Declination (Dec.)+40d25`48.4
Galactic Latitude63.37 degrees
Galactic Longitude175.78 degrees
1997 Distance from Earth71.04 Parallax (milliarcseconds)
 45.91 Light Years
 14.08 Parsecs
2007 Revised Distance from Earth71.11 Parallax (milliarcseconds)
 45.87 Light Years
 14.06 Parsecs
Galacto-Centric Distance24,155.66 Light Years / 7,406.00 Parsecs
Proper Motion Dec.54.64 ± 0.17 milliarcseconds/year
Proper Motion RA.-317.01 ± 0.25 milliarcseconds/year
B-V Index0.62
Radial Velocity11.45 ± 0.07 km/s
Iron Abundance0.00 ± 0.00 Fe/H
Spectral TypeG0V
Colour(G) White to Yellow

Companions (Multi-Star and Exoplanets) Facts

Exoplanet Count3

Estimated Facts

Luminosity (x the Sun)1.0000000
Calculated Effective Temperature5,824 Kelvin
Mass Compared to the Sun1.03

Sources and Links

SIMBAD SourceLink

Related Stars

List of Extrasolar Planets orbiting Chalawan

NameStatusMass (Jupiters)Orbital Period (Days)EccentricityDiscoveredSemi-Major AxisPeriastron
47 Uma BConfirmed2.531078.0000.03219962.1334.000
47 Uma CConfirmed0.542391.0000.09820013.6295.000
47 Uma DConfirmed1.6414002.0000.16201011.6110.000

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