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RU Lupi, HD142560, HIP78094

RU Lupi is a white to yellow eruptive main sequence dwarf star that can be located in the constellation of Lupus. The star can not be seen by the naked eye, you need a telescope to see it.

HIP78094 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD142560.

RU Lupi has alternative name(s), RU Lup.

Location of RU Lupi

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 RU Lupi, the location is 15h 56m 42.32 and -37d 49` 15.3 .

Proper Motion of RU Lupi

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 -26.41 ± 2.12 miliarcseconds/year towards the north and -10.61 ± 3.55 miliarcseconds/year east if we saw them in the horizon.

RU 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 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, Radius) of RU Lupi

RU Lupi has a spectral type of G5Vpe. This means the star is a white to yellow main sequence dwarf star. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

RU Lupi Apparent and Absolute Magnitudes

RU Lupi has an apparent magnitude of 11.09 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 4.28 If you used the 2007 Parallax value, you would get an absolute magnitude of 5.68. 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 RU Lupi

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 4.34 which gave the calculated distance to RU Lupi as 751.53 light years away from Earth or 230.41 parsecs. It would take a spaceship travelling at the speed of light, 751.53 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 8.29 which put RU Lupi at a distance of 393.44 light years or 120.63 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 RU Lupi

The star is a eruptive Irregular 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. RU Lupi brightness ranges from a magnitude of 12.501 to a magnitude of 10.616 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 1.8 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.

RU Lupi Facts

Alternative Names

Traditional/Proper NameRU Lupi
Short NameRU Lup
Hipparcos Library I.D.78094
Henry Draper Designation142560

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude4.28 / 5.68
Visual / Apparent Magnitude11.09
Naked Eye VisibleRequires a 4.5 - 6 Inch Telescope - Magnitudes
Right Ascension (R.A.)15h 56m 42.32
Declination (Dec.)-37d 49` 15.3
Galactic Latitude11.89 degrees
Galactic Longitude338.65 degrees
1997 Distance from Earth4.34 Parallax (milliarcseconds)
 751.53 Light Years
 230.41 Parsecs
2007 Revised Distance from Earth8.29 Parallax (milliarcseconds)
 393.44 Light Years
 120.63 Parsecs
Proper Motion Dec.-26.41 ± 2.12 milliarcseconds/year
Proper Motion RA.-10.61 ± 3.55 milliarcseconds/year
B-V Index-99.00
Radial Velocity-6.40 ± 3.40 km/s
Spectral TypeG5Vpe
Colour(G) White to Yellow

Variable Star Details

Variable Star ClassEruptive
Variable Star TypeIrregular
Mean Variability Period in Days1.839
Variable Magnitude Range (Brighter - Dimmer)10.616 - 12.501
Luminosity (x the Sun)1.0000000

Sources and Links

SIMBAD SourceLink

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