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HD 25171 - HIP18387

HD 25171 is a blue to white main sequence dwarf star that can be located in the constellation of Reticulum. The star can not be seen by the naked eye, you need a telescope to see it. The star has an estimated age of 4.30 Billion of Years but could be as young as 3.10 to 5.70 according to Hipparcos.

HIP18387 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD25171. HD 25171 has at least 1 Extrasolar Planets believed to be in orbit around the star.

Location of HD 25171

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 HD 25171, the location is 03h 55m 49.24 and -65d11`12.7 .

Proper Motion of HD 25171

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 80.69 ± 0.41 miliarcseconds/year towards the north and 143.97 ± 0.45 miliarcseconds/year east if we saw them in the horizon.

HD 25171 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 HD 25171

HD 25171 has a spectral type of F8V. This means the star is a blue to white main sequence dwarf star. The star is 7394.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24116.5176553600000000s. The star has a B-V Colour Index of 0.55 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,082 Kelvin.

HD 25171 Radius has been calculated as being 1.31 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 914,651.04.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.29. 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 1.00 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 -0.110000, 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 4.30 Billion years old but could be between 3.10 and 5.70 Billion years old. In comparison, the Sun's age is about 4.6 Billion Years Old.

HD 25171 Apparent and Absolute Magnitudes

HD 25171 has an apparent magnitude of 7.77 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 4.03 If you used the 2007 Parallax value, you would get an absolute magnitude of 4.07. 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 HD 25171

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 17.84 which gave the calculated distance to HD 25171 as 182.83 light years away from Earth or 56.05 parsecs. It would take a spaceship travelling at the speed of light, 182.83 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 18.19 which put HD 25171 at a distance of 179.31 light years or 54.98 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 7,394.00 Parsecs or 24,116.52 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.

HD 25171 Facts

Alternative Names

Traditional/Proper NameHD 25171
Hipparcos Library I.D.18387
Henry Draper Designation25171

Visual Facts

Star Typemain sequence dwarf star
Age4.30 Billion Years Old
Age Range3.10 - 5.70 Billion Years Old
Absolute Magnitude4.03 / 4.07
Visual / Apparent Magnitude7.77
Naked Eye VisibleRequires a 7x50 Binoculars - Ref: Wiki
Right Ascension (R.A.)03h 55m 49.24
Declination (Dec.)-65d11`12.7
Galactic Latitude-42.29 degrees
Galactic Longitude278.81 degrees
1997 Distance from Earth17.84 Parallax (milliarcseconds)
 182.83 Light Years
 56.05 Parsecs
2007 Revised Distance from Earth18.19 Parallax (milliarcseconds)
 179.31 Light Years
 54.98 Parsecs
Galacto-Centric Distance24,116.52 Light Years / 7,394.00 Parsecs
Proper Motion Dec.80.69 ± 0.41 milliarcseconds/year
Proper Motion RA.143.97 ± 0.45 milliarcseconds/year
B-V Index0.55
Radial Velocity43.64 ± 0.00 km/s
Iron Abundance-0.15 ± 0.08 Fe/H
Spectral TypeF8V
Colour(F) blue to white

Companions (Multi-Star and Exoplanets) Facts

Exoplanet Count1

Estimated Facts

Luminosity (x the Sun)1.0000000
Calculated Effective Temperature6,082 Kelvin
Mass Compared to the Sun1.00
Metallicity-0.11000

Sources and Links

SIMBAD SourceLink

Related Stars


List of Extrasolar Planets orbiting HD 25171


NameStatusMass (Jupiters)Orbital Period (Days)EccentricityDiscoveredSemi-Major AxisPeriastron
Hd 25171 BConfirmed0.951845.0000.0820103.0296.000

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