HIP35442 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD57118.
BD number is the number that the star was filed under in the Durchmusterung or Bonner Durchmusterung, a star catalogue that was put together by the Bonn Observatory between 1859 to 1903. The star's BD Number is BD-19 1813.
More details on objects' alternative names can be found at Star Names .
The location of the supergiant 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 HD 57118, the location is 07h 19m 01.92 and -19° 16` 49.1 .
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 2.90 ± 0.27 miliarcseconds/year towards the north and -2.60 ± 0.39 miliarcseconds/year east if we saw them in the horizon.
The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is 61.80 km/s with an error of about 2.00 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.
HD 57118 has a spectral type of F2Ia. This means the star is a blue to white supergiant star. The star has a B-V Colour Index of 0.61 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,852 Kelvin.
HD 57118 has an apparent magnitude of 6.06 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 If you used the 2007 Parallax value, you would get an absolute magnitude of -5.67. 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.
Using the original Hipparcos data that was released in 1997, the parallax to the star was given as -0.44 which gave the calculated distance to HD 57118 as -7412.80 light years away from Earth or -2272.73 parsecs. It would take a spaceship travelling at the speed of light, -7412.80 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 0.45 which put HD 57118 at a distance of 7248.07 light years or 2222.22 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 458,362,583.82 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. HD 57118 brightness ranges from a magnitude of 6.229 to a magnitude of 6.189 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.0 days (variability).
|Primary / Proper / Traditional Name||HD 57118|
|Alternative Names||HD 57118, HIP 35442, BD-19 1813|
|Constellation's Main Star||No|
|Multiple Star System||No / Unknown|
|Star Type||very luminous Supergiant Star|
|Colour||Yellow - White|
|Absolute Magnitude||/ -5.67|
|Visual / Apparent Magnitude||6.06|
|Naked Eye Visible||Yes - Magnitudes|
|Right Ascension (R.A.)||07h 19m 01.92|
|Declination (Dec.)||-19° 16` 49.1|
|Galactic Latitude||-2.85 degrees|
|Galactic Longitude||233.17 degrees|
|1997 Distance from Earth||-0.44 Parallax (milliarcseconds)|
|-7412.80 Light Years|
|2007 Distance from Earth||0.45 Parallax (milliarcseconds)|
|7248.07 Light Years|
|458,362,583.82 Astronomical Units|
|Proper Motion Dec.||2.90 ± 0.27 milliarcseconds/year|
|Proper Motion RA.||-2.60 ± 0.39 milliarcseconds/year|
|Radial Velocity||61.80 ± 2.00 km/s|
|Mean Variability Period in Days||0.037|
|Variable Magnitude Range (Brighter - Dimmer)||6.189 - 6.229|
|Effective Temperature||5,852 Kelvin|