Stellarium Question

[Colin_Fraser]

I have just been asked why are some stars and their description are blue in color while others are white.
I told him maybe just for visual reasons but I just don't know.
Anyone shed some light on this.

Thanks in advance

[mithrandir]

Colin, it's the star's surface temperature that determines the colour. The black body relationship gives the peak of the intensity curve:

Wavelength ( micrometers) = 2897 / Temperature (K)

CSIRO outreach has this (http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html) explanation.

[Barrykgerdes]

The Stellarium star data base also has a code for the star type and temperature in the entry. The colour information is used to display the star. This colour information also sets the colour of the description, a bit of nuisance at times if it is dark blue as it makes the description much harder to read.

Barry

[Colin_Fraser]

Thanks Andrew and Barry. I'll pass that info on to Tom. He turned 90 years old last week and decided to take up astronomy.