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GUM 23 (aka RCW 38)

STAR FORMATION REGION IN VELA (THE SAILS)

(Image centered at: ra 09 h: 00 m / dec -47º 33')

CLICK THE IMAGE FOR A HIGH RESOLUTION VIEW

February 2025, Home Backyard in Martinez, Buenos Aires, Argentina

DATA

TYPE: Open Cluster

APPARENT DIAMETER: approximately 15 x 20  arc minutes in diameter

APPARENT MAGNITUDE (V): n/a

DISTANCE: approximately 5.500 light years

IMAGE INFORMATION

INSTRUMENT: 6" ORION OPTICS UK (Ultra Grade Optics) w/Sky Watcher Coma Corrector (0.9x) working at at f4.5

CAMERA: QHY 183 MONO

MOUNT: VIXEN GDPX, OAG with Starlight Xpress Lodestar

FILTERS: BAADER LRGB Set + ANTLIA HA 4nm

SKY CONDITIONS: urban skies - Bortle 8

EXPOSURES: HaRGB (150,60,60,60)

OBJECT DESCRIPTION AND IMAGE SESSION

Gum 23 , also known as RCW 38, is giant star formation region at the boundary of Vela OB1 association. It is a blister and compact HII region lying just inside the hedge of a giant molecular cloud ionized by the enormous star cluster G267.92.01.06 that is less than 1 million year old and contains about 2000 stars and hundreds of them are hot O.B. type stars. The mentioned cluster is not visible in the image however following SIMBAD is within the nebula in the center right of the image with a "lip shape". Australian Astronomer Stanley Colin Gum describes this as a "Group of small fragments - possibly one object broken up by foreground obscuration. (*)

This area is very hard to image, even herder from light polluted skies. There are a lot of thin dusty clouds that merges within the emission material which blocks the light of the background nebulosity and even stars. FZ Velorum (the bright star left of centre) is a fifth magnitude A-class foreground star at a distance of 2,225 light years, about half the distance to Gum 23.

(*) Galaxy Map.