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HD 31527, HIP22905

HD 31527 is a white to yellow main sequence dwarf star that can be located in the constellation of Lepus. The star can not be seen by the naked eye, you need a telescope to see it. The star has an estimated age of 5.50 Billion of Years but could be as young as 2.40 to 8.70 according to Hipparcos. HD 31527 has at least 3 Extrasolar Planets believed to be in orbit around the star.

HD 31527's Alternative Names

HIP22905 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD31527.

More details on star alternative names can be found at Star Names.

Location of HD 31527

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 31527, the location is 04h 55m 38.42 and -23° 14` 31.9 .

Proper Motion of HD 31527

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 130.25 ± 0.40 miliarcseconds/year towards the north and -66.21 ± 0.60 miliarcseconds/year east if we saw them in the horizon. The Radial Velocity, that is the speed at which the star is moving away/towards us is 30.40000 km/s with an error of about 0.79 km/s .

HD 31527 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 1.3700000 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Physical Properties (Colour, Temperature, Age) of HD 31527

HD 31527 has a spectral type of G2V. This means the star is a white to yellow main sequence dwarf star. The star is 7423.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24211.1050251200000000s. The star has a B-V Colour Index of 0.6 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,895 Kelvin.

HD 31527 Radius has been calculated as being 1.08 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 752,272.44.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 1.10. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's Iron Abundance is -0.16 with an error value of 0.03 Fe/H with the Sun has a value of 1 to put it into context.

The stars age according to Hipparcos data files put the star at an age of about 5.50 Billion years old but could be between 2.40 and 8.70 Billion years old. In comparison, the Sun's age is about 4.6 Billion Years Old.

HD 31527 Apparent and Absolute Magnitudes

HD 31527 has an apparent magnitude of 7.49 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 4.59 If you used the 2007 Parallax value, you would get an absolute magnitude of 4.56. 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 31527

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 26.31 which gave the calculated distance to HD 31527 as 123.97 light years away from Earth or 38.01 parsecs. It would take a spaceship travelling at the speed of light, 123.97 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 25.93 which put HD 31527 at a distance of 125.79 light years or 38.57 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 7,423.00 Parsecs or 24,211.11 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.

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HD 31527 Facts

Visual Facts

 HD 31527
Alternative NamesHD 31527, HIP 22905
Spectral TypeG2V
Multiple Star systemNo / Unknown
Star Type main sequence Dwarf Star
Colour white to yellow
GalaxyMilky Way
Age5.50 Billion Years Old
Age Range2.40 - 8.70 Billion Years Old
Absolute Magnitude4.59 / 4.56
Visual / Apparent Magnitude7.49
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)04h 55m 38.42
Declination (Dec.)-23° 14` 31.9
Galactic Latitude-35.15 degrees
Galactic Longitude223.39 degrees
1997 Distance from Earth26.31 Parallax (milliarcseconds)
 123.97 Light Years
 38.01 Parsecs
2007 Distance from Earth25.93 Parallax (milliarcseconds)
 125.79 Light Years
 38.57 Parsecs
Galacto-Centric Distance24,211.11 Light Years / 7,423.00 Parsecs
Proper Motion Dec.130.25 ± 0.40 milliarcseconds/year
Proper Motion RA.-66.21 ± 0.60 milliarcseconds/year
B-V Index0.60
Radial Velocity30.40 ± 0.79 km/s
Iron Abundance-0.16 ± 0.03 Fe/H
Semi-Major Axis9054.00
Stellar Luminosity (Lsun)1.37

Companions (Multi-Star and Exoplanets) Facts

Exoplanet Count3

Estimated Facts

Calculated Effective Temperature5,895 Kelvin

Sources and Links

SIMBAD SourceLink

List of Extrasolar Planets orbiting HD 31527

NameStatusMass (Jupiters)Orbital Period (Days)EccentricityDiscoveredSemi-Major AxisPeriastronInclination
HD 31527 bConfirmed0.002516.5460.1320110.12532011.000
HD 31527 cConfirmed0.0034551.2840.1120110.26652011.000
HD 31527 dConfirmed0.0257274.4900.3820110.81812011.000

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