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KW Lupi

KW Lupi Facts

KW Lupi's Alternative Names

HIP77199 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD140637.

KW Lupi has alternative name(s) :- , KW Lup.

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

Location of KW Lupi

The location of the main sequence star in the night sky 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 object is compared to the celestial equator and is expressed in degrees. For KW Lupi, the location is 15h 45m 47.65 and -30° 20` 54.9 .

Radial Velocity and Proper Motion of KW Lupi

Proper Motion

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 -98.40 ± 0.71 milliarcseconds/year towards the north and -69.11 ± 1.30 milliarcseconds/year east if we saw them in the horizon.

Radial Velocity

The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is -5.20 km/s with an error of about 0.40 km/s . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.

KW Lupi 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 0.37 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) of KW Lupi

KW Lupi Colour and Temperature

KW Lupi has a spectral type of K2V. This means the star is a orange to red main sequence star. The star has a B-V Colour Index of 1.04 which means the star's temperature is about 4,773 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu at being .

KW Lupi Radius

Radius has been calculated as being 0.75 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 519,688.39.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 0.74. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

KW Lupi Apparent and Absolute Magnitudes

KW Lupi has an apparent magnitude of 9.37 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 6.31 If you used the 2007 Parallax value, you would get an absolute magnitude of 6.34. 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 KW Lupi

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 24.44 which gave the calculated distance to KW Lupi as 133.45 light years away from Earth or 40.92 parsecs. If you want that in miles, it is 89,493,789,140.

In 2007, Hipparcos data was revised with a new parallax of 24.78 which put KW Lupi at a distance of 131.62 light years or 40.36 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.

Using the 2007 distance, the star is roughly 8,324,789.57 Astronomical Units from the Earth/Sun give or take a few. An Astronomical Unit is the distance between Earth and the Sun. The number of A.U. is the number of times that the star is from the Earth compared to the Sun.

The star's Galacto-Centric Distance is 7,364.00 Parsecs or 24,018.67 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Travel Time to KW Lupi

The time it will take to travel to this star is dependent on how fast you are going. U.G. has done some calculations as to how long it will take going at differing speeds. A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

The New Horizons space probe is the fastest probe that we've sent into space at the time of writing. Its primary mission was to visit Pluto which at the time of launch (2006), Pluto was still a planet.

DescriptionSpeed (m.p.h.)Time (years)
Walking422,066,640,177.25
Car120735,554,672.57
Airbus A380736119,927,392.27
Speed of Sound (Mach 1)767.269115,039,915.22
Concorde (Mach 2)1,534.5457,519,882.64
New Horizons Probe33,0002,674,744.26
Speed of Light670,616,629.00131.62

Variable Type of KW Lupi

The star is a pulsating Semi-Regular Star w 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. KW Lupi brightness ranges from a magnitude of 9.583 to a magnitude of 9.398 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.2 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 Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

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Additional KW Lupi Facts and Figures

Visual Facts


Primary / Proper / Traditional NameKW Lupi
Alternative NamesHD 140637, HIP 77199, KW Lup
Spectral TypeK2V
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star Type Main Sequence Dwarf Star
ColourOrange to Red
GalaxyMilky Way
ConstellationLupus
Absolute Magnitude 6.31 / 6.34
Visual / Apparent Magnitude9.37
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)15h 45m 47.65
Declination (Dec.)-30° 20` 54.9
Galactic Latitude19.02 degrees
Galactic Longitude341.93 degrees
1997 Distance from Earth24.44 Parallax (milliarcseconds)
 133.45 Light Years
 40.92 Parsecs
2007 Distance from Earth24.78 Parallax (milliarcseconds)
 131.62 Light Years
 40.36 Parsecs
 8,324,789.57 Astronomical Units
Galacto-Centric Distance24,018.67 Light Years / 7,364.00 Parsecs
Proper Motion Dec.-98.40 ± 0.71 milliarcseconds/year
Proper Motion RA.-69.11 ± 1.30 milliarcseconds/year
B-V Index1.04
Radial Velocity-5.20 ± 0.40 km/s
Eccentricity0.06
Semi-Major Axis6934.00
Stellar Luminosity (Lsun)0.37

Companions (Multi-Star and Exoplanets) Facts


Exoplanet CountNone/Unaware

Variable Star Details


Variable Star ClassPulsating
Variable Star TypeSemi-Regular Star w
Mean Variability Period in Days0.156
Variable Magnitude Range (Brighter - Dimmer)9.398 - 9.583

Estimated Calculated Facts


Radius (x the Sun)0.74
Effective Temperature4,773 Kelvin

Sources and Links


SIMBAD SourceLink

Related Stars


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