Universe Guide

DF Crucis

DF Crucis Facts

  • DF Crucis is a giant star that can be located in the constellation of Crux. The description is based on the spectral class.
  • DF Crucis is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (B0.5III) of the star, the star's colour is blue .
  • The star can not be seen by the naked eye, you need a telescope to see it.
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 29651.21 light years away from us. Distance

DF Crucis's Alternative Names

HIP58783 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD104705.

DF Crucis has alternative name(s) :- DF Cru, DF Cru.

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

Location of DF Crucis

The location of the giant 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 Crucis, the location is 12h 03m 23.92 and -62° 41` 45.8 .

Radial Velocity and Proper Motion of DF Crucis

Proper Motion

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 0.36 ± 0.47 milliarcseconds/year towards the north and -5.37 ± 0.64 milliarcseconds/year east if we saw them in the horizon.

Radial Velocity

The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is -17.00000 km/s with an error of about 7.40 km/s . 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 of DF Crucis

DF Crucis Temperature and Colour

Based on the star's spectral type of B0.5III , DF Crucis's colour and type is blue giant star. The star has a B-V Colour Index of -0.04 which means the star's temperature is about 10,195 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu.

DF Crucis Radius

DF Crucis estimated radius has been calculated as being 12.95 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 9,008,336.28.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 75.196507161463320306271004050. The figure is derived at by using the formula from SDSS rather than peer reviewed papers. It has been known to produce widely incorrect figures.

DF Crucis Apparent and Absolute Magnitudes

DF Crucis has an apparent magnitude of 7.79 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 -3.18 If you used the 2007 Parallax value, you would get an absolute magnitude of -7.00. 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 Crucis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 0.64000 which gave the calculated distance to DF Crucis as 5096.30 light years away from Earth or 1562.5 parsecs. If you want that in miles, it is about 29,959,238,489,355,631.64, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 0.11000 which put DF Crucis at a distance of 29651.21 light years or 9090.91 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 1,875,121,723.73 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 Crucis

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)
Airbus A38073627,017,112,086.92
Speed of Sound (Mach 1)767.26925,916,066,589.39
Concorde (Mach 2)1,534.5412,958,016,406.20
New Horizons Probe33,000602,563,469.57
Speed of Light670,616,629.0029,651.21
DF Crucis brightness ranges from a magnitude of 7.841 to a magnitude of 7.783 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 1.1 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.

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Additional DF Crucis Facts and Figures

Visual Facts

Primary / Proper / Traditional NameDF Crucis
Alternative NamesDF Cru, HD 104705, HIP 58783, DF Cru
Spectral TypeB0.5III
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeGiant Star
GalaxyMilky Way
Absolute Magnitude -3.18 / -7.00
Visual / Apparent Magnitude7.79
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)12h 03m 23.92
Declination (Dec.)-62° 41` 45.8
Galactic Latitude-0.33629846 degrees
Galactic Longitude297.45470455 degrees
1997 Distance from Earth0.64000 Parallax (milliarcseconds)
 5096.30 Light Years
 1562.5 Parsecs
2007 Distance from Earth0.11000 Parallax (milliarcseconds)
 29651.21 Light Years
 9090.91 Parsecs
 1,875,121,723.73 Astronomical Units
Proper Motion Dec.0.36000 ± 0.47000 milliarcseconds/year
Proper Motion RA.-5.37000 ± 0.64000 milliarcseconds/year
B-V Index-0.04
Radial Velocity-17.00000 ± 7.40 km/s

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Mean Variability Period in Days1.135
Variable Magnitude Range (Brighter - Dimmer)7.783 - 7.841

Estimated Calculated Facts

Radius (x the Sun)75.20
Effective Temperature10,195 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

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