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38 Cancri - HD73575 - HIP42485

38 Cancri is a blue to white pulsating giant star that can be located in the constellation of Cancer. HIP42485 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD73575. 38 Cancri has alternative name(s), 38 Cancri , BT_Cnc, 38 Cnc.

Location of 38 Cancri

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 38 Cancri, the location is 08h 39m 42.68 and +19d46`42.5 .

Proper Motion of 38 Cancri

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 -012.01 ± 000.35 towards the north and -037.43 ± 000.64 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 38 Cancri

38 Cancri has a spectral type of F0III. This means the star is a blue to white giant star. The star has a B-V Colour Index of 0.24 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 7,538 Kelvin.

38 Cancri has been calculated as 4.17 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,903,151.98.km.

38 Cancri Apparent and Absolute Magnitudes

38 Cancri has an apparent magnitude of 6.65 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 0.59 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.41. 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 38 Cancri

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 6.14 which gave the calculated distance to 38 Cancri as 531.21 light years away from Earth or 162.87 parsecs. It would take a spaceship travelling at the speed of light, 531.21 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 5.65 which put 38 Cancri at a distance of 577.28 light years or 176.99 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.

Variable Type of 38 Cancri

The star is a pulsating Delta Scuti 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. 38 Cancri brightness ranges from a magnitude of 7.000 to a magnitude of 7.000 over its variable period. The smaller the magnitude, the brighter the star.

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 Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

38 Cancri Facts

Alternative Names

Traditional Name38 Cancri
Short NameBT Cnc, 38 Cnc
Alternative Name(s)38 Cancri
Hipparcos Library I.D.42485
Bonner DurchmusterungBD+20 2149
Henry Draper Designation73575

Visual Facts

Star Typegiant star
Absolute Magnitude0.59 / 0.41
Apparent Magnitude6.65
Right Ascension (R.A.)08h 39m 42.68
Declination (Dec.)+19d46`42.5
1997 Distance from Earth6.14 Parallax (milliarcseconds)
 531.21 Light Years
 162.87 Parsecs
2007 Revised Distance from Earth5.65 Parallax (milliarcseconds)
 577.28 Light Years
 176.99 Parsecs
Proper Motion Dec.-12.01 ± 0.35 milliarcseconds/year
Proper Motion RA.-37.43 ± 0.64 milliarcseconds/year
B-V Index0.24
Spectral TypeF0III
Colour(F) blue to white

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeDelta Scuti

Estimated Facts

Radius (x the Sun)4.17
Calculated Effective Temperature7,538 Kelvin

Sources and Links

SIMBAD SourceLink

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