Elephant Trunk Nebula (IC 1396)

History

The galactic nebula IC 1396 was discovered photographically in August 1893 by the astronomer Edward Barnard. ^[196] The Canadian astronomer Sidney van den Bergh discovered a reflection nebula on the photo plates of the "Palomar Sky Survey" in the elephant trunk near the star BD + 57 ° 2309 (HD 239710), which he recorded as vdB 142 in his 1966 catalog of reflection nebulae. He noted: Type I-II (star partly inside, partly outside the nebula), moderate brightness, color blue, very strong absorption, radius 0.3 '(red) to 0.6' (blue). ^[255]

Physical Properties

IC 1396 is a large H-II region with an angular diameter of about 3°, which is home to areas of active star formation, so-called globules. The most noticeable globule is the Elephant Trunk Nebula (also often referred to as IC 1396A). This is illuminated by the trapezoid-like, variable O-type multiple star system HD 206267 located 4.5 pc away (see Fig. 3). According to Gaia DR2 measurements, this star is 945+90-73 pc from Earth. The main structure of IC 1396A measures approximately 5.4 arcminutes (about 1.4 pc) in diameter. Behind it, more dark globules and ionized, glowing gas extend over half a degree. This structure is only a small part of the large, bubble-shaped nebula around the star cluster Trumpler 37 or Collinder 439, which typically contains many variables for a young star cluster. ^{[360, 361]}

Revised+Historic NGC/IC Version 22/9, © 2022 Dr. Wolfgang Steinicke ^[277]
Name	RA	Dec	Type	Dim	MD	Dreyer Description	Identification, Remarks
IC 1396	21 38 54.0	+57 29 20	EN	170 × 140	0.800	Neb part of M. Way	LBN 451/452; SG 1.19
IC 1396 A	21 35 30.0	+57 23 00	EN	14 × 2		Neb part of M. Way	LBN 452
IC 1396 B	21 34 30.0	+57 28 00	EN	12 × 4		Neb part of M. Way	LBN 451

Finder Chart

The galactic nebula IC 1396 is located in the constellation Cepheus, which is best visible from May to December.