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Lambda Pavonis, HD173948, HIP92609

Lambda Pavonis is a blue eruptive giant star that can be located in the constellation of Pavo. Lambda Pavonis is the brightest star in Pavo based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Lambda Pavonis is the Bayer Classification for the star. HIP92609 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD173948.

Lambda Pavonis has alternative name(s), lam Pav.

Location of Lambda Pavonis

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 Lambda Pavonis, the location is 18h 52m 13.04 and -62d11`15.2 .

Proper Motion of Lambda Pavonis

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 -13.02 ± 0.12 miliarcseconds/year towards the north and -1.86 ± 0.18 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of Lambda Pavonis

Lambda Pavonis has a spectral type of B2II-III. This means the star is a blue giant star. The star is 7047.00000000 Parsecs from the Galactic Centre or terms of Light Years is 22984.7308516800000000s. The star has a B-V Colour Index of -0.15 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 13,674 Kelvin.

Lambda Pavonis Radius has been calculated as being 13.22 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 9,196,887.16.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 10.45. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Lambda Pavonis Apparent and Absolute Magnitudes

Lambda Pavonis has an apparent magnitude of 4.22 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 -4.50 If you used the 2007 Parallax value, you would get an absolute magnitude of -3.99. 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 Lambda Pavonis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 1.80 which gave the calculated distance to Lambda Pavonis as 1812.02 light years away from Earth or 555.56 parsecs. It would take a spaceship travelling at the speed of light, 1812.02 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 2.28 which put Lambda Pavonis at a distance of 1430.54 light years or 438.60 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 7,047.00 Parsecs or 22,984.73 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 Lambda Pavonis

The star is a eruptive Gamma Cassiopeiae 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. Lambda Pavonis brightness ranges from a magnitude of 4.204 to a magnitude of 4.131 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.1 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.

Lambda Pavonis Facts

Alternative Names

Short Namelam Pav
Bayer DesignationLambda Pavonis
Hipparcos Library I.D.92609
Henry Draper Designation173948

Visual Facts

Star Typegiant star
Absolute Magnitude-4.50 / -3.99
Visual / Apparent Magnitude4.22
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)18h 52m 13.04
Declination (Dec.)-62d11`15.2
Galactic Latitude-23.87 degrees
Galactic Longitude333.61 degrees
1997 Distance from Earth1.80 Parallax (milliarcseconds)
 1812.02 Light Years
 555.56 Parsecs
2007 Revised Distance from Earth2.28 Parallax (milliarcseconds)
 1430.54 Light Years
 438.60 Parsecs
Galacto-Centric Distance22,984.73 Light Years / 7,047.00 Parsecs
Proper Motion Dec.-13.02 ± 0.12 milliarcseconds/year
Proper Motion RA.-1.86 ± 0.18 milliarcseconds/year
B-V Index-0.15
Radial Velocity9.00 ± 4.10 km/s
Spectral TypeB2II-III
Colour(B) blue

Variable Star Details

Variable Star ClassEruptive
Variable Star TypeGamma Cassiopeiae
Mean Variability Period in Days0.138
Variable Magnitude Range (Brighter - Dimmer)4.131 - 4.204

Estimated Facts

Calculated Effective Temperature13,674 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.


Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
173948-62 5983.4A4.400000.00000-18.00000B3Blue/White
B12.400001917

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