Carina Nebula Details: The Caterpillar

A Bok globule nicknamed the "caterpillar" appears at the right. Its glowing edge indicates that it is being photoionized by the hottest stars in the cluster. It has been hypothesized that stars may form inside such dusty cocoons. The top of the Keyhole Nebula, the most prominent feature embedded inside Carina, is on the left. Another Bok globule is in the foreground.

About the colours

This image is a composite of many separate exposures made by the ACS instrument on the Hubble Space Telescope along with ground-based observations. In total, three filters were used to sample narrow wavelength emission. The color results from assigning different hues (colors) to each monochromatic image. In this case, the assigned colors are:Luminosity*: F658N (H-alpha+[N II])Blue: CTIO ([O III] 501nm)Green: CTIO (H-alpha+[N II] 658nm)Red: CTIO ([S II] 672+673nm)*The higher resolution, black & white Hubble image and the lower resolution, color CTIO images were combined using a technique that takes luminosity (brightness) information from the black and white ACS image and color information from the composite CTIO image. This preserves all of the higher-resolution detail from the Hubble data while rendering a color image representing the physical processes in this active region of space.

About the data

This color image combines many exposures from Hubble Space Telescope's Advanced Camera for Surveys (ACS)* and NOAO/AURA/NSF Cerro-Tololo Interamerican Observatory's (CTIO) 4m Blanco Telescope and MOSAIC2 camera. The ACS data was from the HST proposal 10241 : N. Smith (University of California, Berkeley), J. Bally (University of Colorado at Boulder), N. Walborn (STScI), and J. Morse (NASA/GSFC). *A small area of the Hubble ACS image that was saturated around the brightest star in the field, Eta Carinae, was replaced with images from previous shorter exposures from Hubble's Wide Field Planetary Camera 2.

The CTIO observing team includes: N. Smith (University of California, Berkeley), J. Bally (University of Colorado at Boulder), and J. Walawender (Institute for Astronomy/University of Hawaii). *A small area of the Hubble ACS image that was saturated around the brightest star in the field, Eta Carinae, was replaced with images from previous shorter exposures from Hubble's Wide Field Planetary Camera 2.