Planetary Nebula IRAS 18333-2357 in M22 -

IRAS 18333-2357

(PK 009-07.1, GJJC 1) in globular cluster

Planetary nebula IRAS 18333-2357 or GJJC1 in M22 was discovered by the

infrared satellite IRAS (F.C. Gillett, Astrophys. J. 338, 862, 1989). This

faint object is of about 15th visual magnitude and only 3 arc seconds

diameter. Lying 1′ south of the center of M22, the nebula is an extreme

observer’s challenge:

It is Rich Jakiel’s

Doug Snyder has an excellent

observer’s page with locating info and images; we adopted the image

on the right from there.

Below we present images of the faint planetary nebula IRAS 18333-2357:

This is a small region in the globular cluster M22, a dense star cluster

about 3 kpc away. Near the center is a very unusual planetary nebula

discovered by its distinctive infra-red emission with the IRAS satellite.

The nebula is almost undetectable in this image.

This is the exact same picture as the M22 picture above, but a continuum

image was subtracted from the {OIII} image above to enhance the visibility

of the emission-line nebula. The “dual headlight” white spots just above

the center of the picture show the brightest parts of the nebula, but there

are also faint wisps tailing away and downward. This nebula is extremely

bizarre in that (1) it is only 1 of 2 known in globular clusters, (2) it is

only 1 of 4 known to be completely devoid of hydrogen, and (3) it is only

1 of about 3 known to be sweeping through the interstellar medium. The

central star is the bright star in the middle of the picture.

Credit: George Jacoby, KPNO

Last Modification: 12 May 1999, 11:00 MET