Universe Guide

HomeFactsConstellationsLepus

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.

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. HD 31527 has at least 3 Extrasolar Planets believed to be in orbit around the star.

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 -23d14`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.

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 1.0000000 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, Radius) 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.

HD 31527 Facts

Alternative Names

Traditional/Proper NameHD 31527
Hipparcos Library I.D.22905
Henry Draper Designation31527

Visual Facts

Star Typemain sequence dwarf star
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 - Ref: Wiki
Right Ascension (R.A.)04h 55m 38.42
Declination (Dec.)-23d14`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 Revised 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
Spectral TypeG2V
Colour(G) White to Yellow

Companions (Multi-Star and Exoplanets) Facts

Exoplanet Count3

Estimated Facts

Luminosity (x the Sun)1.0000000
Calculated Effective Temperature5,895 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars


List of Extrasolar Planets orbiting HD 31527


NameStatusMass (Jupiters)Orbital Period (Days)EccentricityDiscoveredSemi-Major AxisPeriastron
Hd 31527 BConfirmed0.036316.5460.1320110.1253
Hd 31527 CConfirmed0.049851.2840.1120110.2665
Hd 31527 DConfirmed0.0519274.4900.3820110.8181

Add a Comment


Name:
Email: (Optional)
Comment: