Universe Guide


136 G. Aql, HD194263, HIP100672

136 G. Aql is a orange to red eruptive star that can be located in the constellation of Aquila. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

HIP100672 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD194263. The Id of the star in the Gould Star Catalogue is 136. 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 136 G. Aql

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 136 G. Aql, the location is 20h 24m 41.75 and +01d22`07.0 .

Proper Motion of 136 G. Aql

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 -20.16 ± 0.35 miliarcseconds/year towards the north and 7.40 ± 0.62 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 136 G. Aql

136 G. Aql has a spectral type of K5. This means the star is a orange to red star. The star is 7251.00000000 Parsecs from the Galactic Centre or terms of Light Years is 23650.1040734400000000s. The star has a B-V Colour Index of 1.6 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 3,775 Kelvin.

136 G. Aql Radius has been calculated as being 30.27 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 21,064,972.12.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 26.73. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

136 G. Aql Apparent and Absolute Magnitudes

136 G. Aql 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 -0.71 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.44. 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 136 G. Aql

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 3.77 which gave the calculated distance to 136 G. Aql as 865.15 light years away from Earth or 265.25 parsecs. It would take a spaceship travelling at the speed of light, 865.15 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 4.26 which put 136 G. Aql at a distance of 765.64 light years or 234.74 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 7,251.00 Parsecs or 23,650.10 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 136 G. Aql

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. 136 G. Aql brightness ranges from a magnitude of 6.576 to a magnitude of 6.499 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.

136 G. Aql Facts

Alternative Names

Traditional/Proper Name136 G. Aql
Hipparcos Library I.D.100672
Bonner DurchmusterungBD+00 4496
Gould I.D.136
Henry Draper Designation194263

Visual Facts

Star Type star
Absolute Magnitude-0.71 / -0.44
Visual / Apparent Magnitude6.41
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)20h 24m 41.75
Declination (Dec.)+01d22`07.0
Galactic Latitude-19.95 degrees
Galactic Longitude45.32 degrees
1997 Distance from Earth3.77 Parallax (milliarcseconds)
 865.15 Light Years
 265.25 Parsecs
2007 Revised Distance from Earth4.26 Parallax (milliarcseconds)
 765.64 Light Years
 234.74 Parsecs
Galacto-Centric Distance23,650.10 Light Years / 7,251.00 Parsecs
Proper Motion Dec.-20.16 ± 0.35 milliarcseconds/year
Proper Motion RA.7.40 ± 0.62 milliarcseconds/year
B-V Index1.60
Radial Velocity-65.49 ± 0.21 km/s
Spectral TypeK5
Colour(K) Orange to Red

Variable Star Details

Variable Star ClassEruptive
Variable Star TypeIrregular
Mean Variability Period in Days0.066
Variable Magnitude Range (Brighter - Dimmer)6.499 - 6.576

Estimated Facts

Calculated Effective Temperature3,775 Kelvin

Sources and Links

SIMBAD SourceLink

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