Universe Guide


7 Lyncis - HD46101 - HIP31359

7 Lyncis is a orange to red pulsating giant star that can be located in the constellation of Lynx. HIP31359 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD46101. 7 Lyncis has alternative name(s), 7 Lyncis , BQ_Lyn, 7 Lyn.

Location of 7 Lyncis

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 7 Lyncis, the location is 06h 34m 32.80 and +55d21`10.9 .

Proper Motion of 7 Lyncis

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 005.85 ± 000.32 towards the north and 003.15 ± 000.56 east if we saw them in the horizon.

7 Lyncis 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 96.0000000 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, Radius) of 7 Lyncis

7 Lyncis has a spectral type of K0III:. This means the star is a orange to red giant star. The star has a B-V Colour Index of 1.55 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 3,892 Kelvin.

7 Lyncis has been calculated as 50.19 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 34,918,952.97.km.

7 Lyncis Apparent and Absolute Magnitudes

7 Lyncis has an apparent magnitude of 6.45 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 -1.94 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.91. 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 7 Lyncis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 2.10 which gave the calculated distance to 7 Lyncis as 1553.16 light years away from Earth or 476.19 parsecs. It would take a spaceship travelling at the speed of light, 1553.16 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 3.38 which put 7 Lyncis at a distance of 964.98 light years or 295.86 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.

Variable Type of 7 Lyncis

The star is a pulsating Semiregular s, which are giants or supergiants of intermediate and late spectral 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. This is a some uncertainty as to the type but the type mentioned is the current variable star classification for this star. 7 Lyncis brightness ranges from a magnitude of 7.000 to a magnitude of 6.000 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 63.0 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 Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

7 Lyncis Facts

Alternative Names

Traditional Name7 Lyncis
Short NameBQ Lyn, 7 Lyn
Alternative Name(s)7 Lyncis
Hipparcos Library I.D.31359
Bonner DurchmusterungBD+55 1093
Henry Draper Designation46101

Visual Facts

Star Typegiant star
Absolute Magnitude-1.94 / -0.91
Apparent Magnitude6.45
Right Ascension (R.A.)06h 34m 32.80
Declination (Dec.)+55d21`10.9
1997 Distance from Earth2.10 Parallax (milliarcseconds)
 1553.16 Light Years
 476.19 Parsecs
2007 Revised Distance from Earth3.38 Parallax (milliarcseconds)
 964.98 Light Years
 295.86 Parsecs
Proper Motion Dec.5.85 ± 0.32 milliarcseconds/year
Proper Motion RA.3.15 ± 0.56 milliarcseconds/year
B-V Index1.55
Spectral TypeK0III:
Colour(K) Orange to Red

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSemiregular s, which are giants or supergiants of intermediate and late spectral probably
Mean Variability Period in Days63.000
Variable Magnitude Range (Brighter - Dimmer)6.000 - 7.000

Estimated Facts

Radius (x the Sun)50.19
Luminosity (x the Sun)96.0000000
Calculated Effective Temperature3,892 Kelvin

Sources and Links

SIMBAD SourceLink

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