Question

HD531531 (not a real star) is a 5 solar mass zero age main sequence star at a distance of 100 parsecs. If X has a luminosity 550 times $L^{_{Sun}}$ and the . Write down $F_{\lambda }$, the flux per unit wavelength from this star, in units or ergs .

Answer 1

The flux from a star at a temperature T is given by F=$\sigma$T⁴

Where $\sigma$ is the s=Stefan Boltzmann constant = 5.669 x 10^-8 W/m²K⁴

Here, T = 17180 K

So, F = 17180⁴ x 5.669 x 10^-8 = 4.938 x 10⁹ W/m²

=4.938 x 10¹² ergs cm^-2 s^-1 = 493.8 ergs cm^-2 s^-1 Angstrom^-1