Project Description

Bubble Around Wolf/Rayet 23

I have chosen to image the bubble around the Wolf-Rayet star, WR23 at the north end of the Carina Nebula using three narrowband filters to bring out structural detail. This nebulosity apparently does not have a catalog designation (e.g., RCW, Gum, Trumpler), so I will refer to it as the bubble around WR23.

Wolf-Rayet stars are hot (25,000 – 50,000K) , massive (>20 solar masses) stars. They are undergoing a normal evolution for very massive stars where they lose orders of magnitude more solar mass each year in comparison to our Sun. They do so in the form of a very strong solar wind that interacts with the interstellar medium, often producing “bubbles”, as shown here. Thor’s Helmet (NGC 2359) is a northern example of such a WR “bubble”. C. Cappa, et al.(Astron. & Astrophys, v426, Issue 1, June 2, 2005, p 155) estimate the age to be 700,000 years and a size of the bubble to be about 42 light years in radius, expanding at 10 km/s. The H-a data used to make the color composite is presented below.

Constellation: Carina
Ra: 10hr 41m 38s
Dec: -58d 46m 19s
Image Size: 40′ x 36′
North: Lower right
Image Credit: Don Goldman, PhD

Exposure: 12 hrs Total; 4 hrs H-a, 5 hrs SII, 3 hrs OIII
Telescope: 14.5
Mount: Software Bisque Paramount ME
Oag: Astrodon MonsterMOAG
Acquisition: CCD AutoPilot4
Calibration: CCDStack2
Observatory Site: Riverland Dingo Observatory, Moorook, S. Australia
Camera: Apogee U16M
Filters: Astrodon 5 nm H-a and SII, 3 nm OIII
Guider: SBIG ST-402
Camera Operation: MaximDL5.08
Processing: Photoshop CS3
Image Date: 02/27/2010

View more of Don Goldman’s images at