Universe Guide


SW Pictoris - HD41586 - HIP28596

SW Pictoris is a red pulsating giant star that can be located in the constellation of Pictor. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

HIP28596 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD41586.

SW Pictoris has alternative name(s), SW_Pic.

Location of SW Pictoris

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 SW Pictoris, the location is 06h 02m 09.32 and -60d05`48.7 .

Proper Motion of SW Pictoris

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 8.56 ± 0.32 miliarcseconds/year towards the north and 16.20 ± 0.32 miliarcseconds/year east if we saw them in the horizon.

SW Pictoris 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 7.0000000 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 SW Pictoris

SW Pictoris has a spectral type of M4III. This means the star is a red giant star. The star is 7410.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24168.7037904000000000s. The star has a B-V Colour Index of 1.5 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 3,989 Kelvin.

SW Pictoris Radius has been calculated as being 25.89 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 18,016,305.86.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 30.00. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

SW Pictoris Apparent and Absolute Magnitudes

SW Pictoris has an apparent magnitude of 6.41 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 -0.61 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.93. 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 SW Pictoris

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.95 which gave the calculated distance to SW Pictoris as 825.73 light years away from Earth or 253.16 parsecs. It would take a spaceship travelling at the speed of light, 825.73 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 3.40 which put SW Pictoris at a distance of 959.30 light years or 294.12 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 7,410.00 Parsecs or 24,168.70 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Variable Type of SW Pictoris

The star is a pulsating Slow 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. SW Pictoris brightness ranges from a magnitude of 6.000 to a magnitude of 6.000 over its variable period. The smaller the magnitude, the brighter the star.

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.

SW Pictoris Facts

Alternative Names

Traditional/Proper NameSW Pictoris
Short NameSW Pic
Hipparcos Library I.D.28596
Henry Draper Designation41586

Visual Facts

Star Typegiant star
Absolute Magnitude-0.61 / -0.93
Visual / Apparent Magnitude6.41
Naked Eye VisibleYes - Ref: Wiki
Right Ascension (R.A.)06h 02m 09.32
Declination (Dec.)-60d05`48.7
Galactic Latitude-29.34 degrees
Galactic Longitude268.97 degrees
1997 Distance from Earth3.95 Parallax (milliarcseconds)
 825.73 Light Years
 253.16 Parsecs
2007 Revised Distance from Earth3.40 Parallax (milliarcseconds)
 959.30 Light Years
 294.12 Parsecs
Galacto-Centric Distance24,168.70 Light Years / 7,410.00 Parsecs
Proper Motion Dec.8.56 ± 0.32 milliarcseconds/year
Proper Motion RA.16.20 ± 0.32 milliarcseconds/year
B-V Index1.50
Radial Velocity-51.00 ± 0.60 km/s
Spectral TypeM4III
Colour(M) Red

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeSlow Irregular

Estimated Facts

Luminosity (x the Sun)7.0000000
Calculated Effective Temperature3,989 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

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