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DF Gruis

DF Gruis Facts

DF Gruis's Alternative Names

HIP113442 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD217070.

DF Gruis has alternative name(s) :- DF Gru, DF Gru.

More details on objects' alternative names can be found at Star Names .

Location of DF Gruis

The location of the main sequence star in the night sky 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 object is compared to the celestial equator and is expressed in degrees. For DF Gruis, the location is 22h 58m 31.95 and -42° 17` 16.6 .

Proper Motion of DF Gruis

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 -28.66 ± 1.26 milliarcseconds/year towards the north and 6.44 ± 1.55 milliarcseconds/year east if we saw them in the horizon. . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.

Physical Properties (Colour, Temperature) of DF Gruis

DF Gruis Colour and Temperature

DF Gruis has a spectral type of F3/F5V. This means the star is a yellow to white main sequence star. The star has a B-V Colour Index of 0.45 which means the star's temperature is about 6,500 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu at being .

DF Gruis Radius

Radius has been calculated as being 1.08 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 750,792.94.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 2.97. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

DF Gruis Apparent and Absolute Magnitudes

DF Gruis has an apparent magnitude of 10.27 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 4.17 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.97. 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 DF Gruis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 6.02 which gave the calculated distance to DF Gruis as 541.80 light years away from Earth or 166.11 parsecs. If you want that in miles, it is 363,340,089,592.

In 2007, Hipparcos data was revised with a new parallax of 2.19 which put DF Gruis at a distance of 1489.33 light years or 456.62 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.

Using the 2007 distance, the star is roughly 94,183,979.55 Astronomical Units from the Earth/Sun give or take a few. An Astronomical Unit is the distance between Earth and the Sun. The number of A.U. is the number of times that the star is from the Earth compared to the Sun.

Travel Time to DF Gruis

The time it will take to travel to this star is dependent on how fast you are going. U.G. has done some calculations as to how long it will take going at differing speeds. A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

The New Horizons space probe is the fastest probe that we've sent into space at the time of writing. Its primary mission was to visit Pluto which at the time of launch (2006), Pluto was still a planet.

DescriptionSpeed (m.p.h.)Time (years)
Walking4249,692,366,017.14
Car1208,323,078,867.24
Airbus A3807361,357,023,728.35
Speed of Sound (Mach 1)767.2691,301,720,080.01
Concorde (Mach 2)1,534.54650,859,191.72
New Horizons Probe33,00030,265,741.34
Speed of Light670,616,629.001,489.33

Variable Type of DF Gruis

The star is a eclipsing binary sys Beta Persei (Algol) 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. DF Gruis brightness ranges from a magnitude of 10.785 to a magnitude of 10.352 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 1.4 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.

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Additional DF Gruis Facts and Figures

Visual Facts


Primary / Proper / Traditional NameDF Gruis
Alternative NamesDF Gru, HD 217070, HIP 113442, DF Gru
Spectral TypeF3/F5V
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star Type Main Sequence Dwarf Star
ColourYellow - White
GalaxyMilky Way
ConstellationGrus
Absolute Magnitude 4.17 / 1.97
Visual / Apparent Magnitude10.27
Naked Eye VisibleRequires a 4.5 - 6 Inch Telescope - Magnitudes
Right Ascension (R.A.)22h 58m 31.95
Declination (Dec.)-42° 17` 16.6
Galactic Latitude-62.49 degrees
Galactic Longitude352.17 degrees
1997 Distance from Earth6.02 Parallax (milliarcseconds)
 541.80 Light Years
 166.11 Parsecs
2007 Distance from Earth2.19 Parallax (milliarcseconds)
 1489.33 Light Years
 456.62 Parsecs
 94,183,979.55 Astronomical Units
Proper Motion Dec.-28.66 ± 1.26 milliarcseconds/year
Proper Motion RA.6.44 ± 1.55 milliarcseconds/year
B-V Index0.45

Companions (Multi-Star and Exoplanets) Facts


Exoplanet CountNone/Unaware

Variable Star Details


Variable Star ClassEclipsing binary sys
Variable Star TypeBeta Persei (Algol)
Mean Variability Period in Days1.402
Variable Magnitude Range (Brighter - Dimmer)10.352 - 10.785

Estimated Calculated Facts


Radius (x the Sun)2.97
Effective Temperature6,500 Kelvin

Sources and Links


SIMBAD SourceLink

Related Stars


Comments and Questions

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