Nekkar (Beta Bootis) is a white to yellow giant star that can be located in the constellation of Bootes. Beta Bootis is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR5602. HIP73555 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD133208. Nekkar has alternative name(s), 42 Bootis , 42 Boo.
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 Nekkar, the location is 15h 01m 56.79 and +40d23`26.3 .
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 -028.86 ± 000.11 towards the north and -040.15 ± 000.14 east if we saw them in the horizon.
Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 113.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.
Nekkar has a spectral type of G8III. This means the star is a white to yellow giant star. The star has a B-V Colour Index of 0.95 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,948 Kelvin.
Nekkar has been calculated as 17.06 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 11,872,296.43.km.
Nekkar has an apparent magnitude of 3.49 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 -0.64 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.71. 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 14.91 which gave the calculated distance to Nekkar as 218.75 light years away from Earth or 67.07 parsecs. It would take a spaceship travelling at the speed of light, 218.75 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 14.48 which put Nekkar at a distance of 225.25 light years or 69.06 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 June Bootids Meteor Shower radiants from a point near this star. The meteor shower runs typically between June 27-July 5 with a peak date of Jun. 28/29. The speed of a meteor in the shower is 14 Km/s. The amount of meteors predicted to be seen per hour (Zenith Hourly Rate) is 14. p>
The Quadrantids Meteor Shower radiants from a point near this star. The meteor shower runs typically between Jan 01 - Jan 05 with a peak date of Jan 03. The speed of a meteor in the shower is 41 Km/s. The amount of meteors predicted to be seen per hour (Zenith Hourly Rate) is 41. p>
|Short Name||42 Boo|
|Bayer Designation||Beta Bootis|
|Alternative Name(s)||42 Bootis|
|Hipparcos Library I.D.||73555|
|Yale Bright Star Catalogue (HR) Id||5602|
|Bonner Durchmusterung||BD+40 2840|
|Henry Draper Designation||133208|
|Star Type||giant star|
|Absolute Magnitude||-0.64 / -0.71|
|Right Ascension (R.A.)||15h 01m 56.79|
|1997 Distance from Earth||14.91 Parallax (milliarcseconds)|
|218.75 Light Years|
|2007 Revised Distance from Earth||14.48 Parallax (milliarcseconds)|
|225.25 Light Years|
|Proper Motion Dec.||-28.86 ± 0.11 milliarcseconds/year|
|Proper Motion RA.||-40.15 ± 0.14 milliarcseconds/year|
|Colour||(G) White to Yellow|
|Radius (x the Sun)||17.06|
|Luminosity (x the Sun)||113.0000000|
|Calculated Effective Temperature||4,948 Kelvin|