ABOUT THIS IMAGE:

BAT99-49 is a binary star, consisting of one WR-star and a companion O-type star. Like in the case of BAT99-2, the strong UV-radiation from their WR-star has created He II nebulae around them, well visible in the photos by their blue color.

The nebula around the hot double star BAT99-49 in the Large Magellanic Cloud (LMC) was obtained in January 2002 with the FORS1 multi-mode instrument at the 8.2-m VLT MELIPAL telescope at the Paranal Observatory (Chile). It is based on three exposures through narrow-band optical (interference) filters that isolate the light from specific atoms and ions. In this rendering, the blue color represents the light from singly ionized Helium (He II; wavelength 468.6 nm; exposure time 45 min), green corresponds to doubly ionized oxygen ([O III]; 495.7 + 500.7 nm; 5 min) and red to hydrogen atoms (H; H-alpha line at 656.2 nm; 5 min). Of these three ions, He II is the tracer of high excitation, i.e. the bluest areas of the nebula are the hottest. The sky field measures 400 x 400 square arcsec ; the original pixel size on the 2k x 2k CCD is 0.23 arcsec. North is up and east to the left.