Gum 15 — Emission Nebula in Vela
RA/Dec (J2000): 08h 42m, −42° 55′ (approx.)
Constellation: Vela
Other designations: RCW 32
Historical Overview
Gum 15 is an H II region catalogued by Colin Stanley Gum in 1955 in his pioneering survey of southern emission nebulae (Gum 1955). It is also known as RCW 32 from Rodgers, Campbell, and Whiteoak’s 1960 catalog.
This nebula is part of the Vela Molecular Ridge, a complex of star-forming clouds. Gum 15 is ionized by massive O-type stars within its interior, producing a bright emission structure. Infrared and radio observations in the late 20th century revealed embedded clusters and ongoing star formation within the nebula (Liseau et al. 1992).
Modern astrophotography shows Gum 15 as a red-pink cloud of hydrogen gas, with dark lanes of dust cutting across its structure. Though not as well-known as the Orion Nebula, it is an excellent example of a medium-sized galactic H II region.
Key Facts
- Type: Emission nebula (H II).
- Distance: ~3,000 light-years.
- Size: ~60 light-years across.
- Scientific importance: Ongoing star formation; part of Vela Ridge.
References
Liseau, R. et al. (1992). Star Formation in the Vela Molecular Ridge. A&A, 262, 546.
Gum, C. S. (1955). A Survey of Southern H II Regions. Mem. RAS, 67, 155.
Rodgers, A. W., Campbell, C. T., & Whiteoak, J. B. (1960). A Catalogue of H II Regions. MNRAS, 121, 103.