exoleuv - Estimate the stellar UV countrate for different CMA filters


exoleuv filter sptype vmag bvmag


Exoleuv calculates a rough estimate of the stellar UV count rate in different CMA filter. Many observations of hot stars with EXOSAT showed that UV radiation leaked through the filter to dominate the X-ray count rate for bright enough UV sources. The 'exoleuv' provides an estimate good to 50%. The calculation is based on a UV calibration of the CMA done by Fritz Paerels with Sirius AB combined with an IUE atlas of spectra of hot stars and Seaton's interstellar redding law. The estimates is given only for four of the CMA filters (3000 Lexan, 4000 Lexan, Polypropylene and Aluminum/Parylene) and only for stars of spectral type O,B and A. In all other cases (different filter or star spectral type) the UV count rate is set to zero.


Filter [integer]
The EXOSAT CMA filter number. The input values are 7=3000 Lexan, 2=Polypropylene, 3=4000 Lexan, 6=Aluminum/Parylene.

Sptype [string]
The spectral type of the star e.g. O7 or B3 (no account is taken for the luminosity class).

Vmag [real]
V magnitude of the star.

BVmag [real]
E(B-V) color excess.


Estimate UV rate in the EXOSAT CMA filter 3 (4000 Lexan) for a star of spectral type A1, magnitude 5.38 and E(V-B)=0.02

      > exoleuv filter=3 sptype=A1 vmag=5.38 bvmag=-0.02


sep98 ftools.exosat