Universe Guide


165 G. Sgr, HD181240, HIP95077

165 G. Sgr is a blue star that can be located in the constellation of Sagittarius. 165 G. Sgr is the brightest star in Sagittarius 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.

HIP95077 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD181240. The Id of the star in the Gould Star Catalogue is 165. Stars in the southern hemisphere are more likely to have a Gould Id than the northern hemisphere. For example, there are no Gould classified stars in Ursa Major.

Location of 165 G. Sgr

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 165 G. Sgr, the location is 19h 20m 38.16 and -22d24`09.4 .

Proper Motion of 165 G. Sgr

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 27.33 ± 0.21 miliarcseconds/year towards the north and -10.63 ± 0.35 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 165 G. Sgr

165 G. Sgr has a spectral type of A6:m.... This means the star is a blue star. The star is 7349.00000000 Parsecs from the Galactic Centre or terms of Light Years is 23969.7441505600000000s. The star has a B-V Colour Index of 0.27 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,943 Kelvin.

165 G. Sgr Radius has been calculated as being 2.80 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,951,082.93.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 2.73. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

165 G. Sgr Apparent and Absolute Magnitudes

165 G. Sgr has an apparent magnitude of 5.59 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 1.81 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.87. 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 165 G. Sgr

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 17.52 which gave the calculated distance to 165 G. Sgr as 186.17 light years away from Earth or 57.08 parsecs. It would take a spaceship travelling at the speed of light, 186.17 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 18.06 which put 165 G. Sgr at a distance of 180.60 light years or 55.37 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 7,349.00 Parsecs or 23,969.74 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

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.

165 G. Sgr Facts

Alternative Names

Traditional/Proper Name165 G. Sgr
Hipparcos Library I.D.95077
Bonner DurchmusterungBD-22 5063
Gould I.D.165
Henry Draper Designation181240

Visual Facts

Star Type star
Absolute Magnitude1.81 / 1.87
Visual / Apparent Magnitude5.59
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)19h 20m 38.16
Declination (Dec.)-22d24`09.4
Galactic Latitude-16.16 degrees
Galactic Longitude15.63 degrees
1997 Distance from Earth17.52 Parallax (milliarcseconds)
 186.17 Light Years
 57.08 Parsecs
2007 Revised Distance from Earth18.06 Parallax (milliarcseconds)
 180.60 Light Years
 55.37 Parsecs
Galacto-Centric Distance23,969.74 Light Years / 7,349.00 Parsecs
Proper Motion Dec.27.33 ± 0.21 milliarcseconds/year
Proper Motion RA.-10.63 ± 0.35 milliarcseconds/year
B-V Index0.27
Radial Velocity-7.10 ± 0.50 km/s
Spectral TypeA6:m...
Colour(A) blue

Estimated Facts

Calculated Effective Temperature6,943 Kelvin

Sources and Links

SIMBAD SourceLink

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