Measurement of the absolute monochromatic flux from VEGA at Lambda 2.20 and Lambda 3.80 microns by comparison with a furnace.
Abstract
A determination has been made using the 1 .5-m flux collector at Tenerife of the absolute monochromatic flux from Vega at 2.20 and 3.80 gm by comparison with the flux from a furnace which has been calibrated against a standard blackbody at a known temperature. The technique used is an improvement on one previously used by the authors at Tenerife in 1979. The fluxes found are 3.92×10-10 Wm-2μm-1 at 2.20μm, and 5.28×10-11 Wm-2 μm-1 at 3.80μm, each with an accuracy of about 4 per cent. The new determination of the 2.20μm flux is more reliable than the one obtained at Tenerife in 1979, and it is recommended that the new determination replaces it. Comparison is made with other calibrations and with calculated fluxes. The agreement with other calibrations is good, but comparison with the flux calculations of Dreiling & Bell for their model shows an observed excess flux of 8 per cent at 3.80μm. Suggestions are made to account for this excess. An empirical flux distribution over the wavelength range 1μm < λ < 4μm is proposed with a likely accuracy of 3 per cent.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 1983
- DOI:
- 10.1093/mnras/203.3.795
- Bibcode:
- 1983MNRAS.203..795S
- Keywords:
-
- A Stars;
- Infrared Stars;
- Monochromatic Radiation;
- Radiant Flux Density;
- Black Body Radiation;
- Calibrating;
- Furnaces;
- Stellar Atmospheres;
- Stellar Models;
- Astronomy