Medusa Nebula

Database links to Abell 21 / YM 29

Planetary nebula Abell 21 / YM 29 / Medusa nebula

AladinLite
Constellation	Twins
Position equinox : J2000.0
Right ascension	07h 29m 02.7s
declination	+ 13 ° 14 ′ 48 ″
Appearance
Angular expansion	12 ′
Central star
designation	WD 0726 + 133
Physical data
distance	approx. 1500 ly (approx. 500 pc )
diameter	approx (1.8 × 1.4) pc
history
discovery	George O. Abell / Hugh M. Johnson
Date of discovery	1955
Catalog names
PK 205 + 14 1 • PN G205.1 + 14.2 • Sh 2-274 • Abell 21 • YM 29

Abell 21 or Sharpless 2-274 , also known as the Medusa Nebula, is an extensive planetary nebula with low surface brightness in the constellation Gemini near the ecliptic. The nebula owes its proper name to the snake-like gas filaments that are reminiscent of Medusa 's hair .

It was discovered independently in 1955 by George Ogden Abell at the Palomar Observatory and Hugh M. Johnson as part of the Yerkes-McDonald Survey. Until the 1970s, it was also considered that it might be a supernova remnant . Based on the calculated rate of expansion and the thermal nature of the radio emission, Soviet astronomers concluded in 1971 that the original classification is the most likely.

The object should not be confused with the galaxy cluster Abell 21 or the merging galaxies NGC 4194 , which are sometimes associated with the head of Medusa due to their appearance.

Web links

Medusa nebula, Abell 21 , high-resolution images from the 4m Mayall telescope
ESO: The Terrible Beauty of Medusa May 20, 2015 - + photos, map & animation
Spektrum .de: amateur recordings [1] [2]

Individual evidence

^ MEDUSA - Planetary Nebula . Center de Données astronomiques de Strasbourg. Retrieved July 1, 2010.
↑ Cutri, RM; Skrutskie, MF; van Dyk, S .; Beichman, CA, et al: 2MASS All Sky Catalog of point sources. . In: The IRSA 2MASS All-Sky Point Source Catalog, NASA / IPAC Infrared Science Archive. . . bibcode : 2003tmc..book ..... C .
^ Robert Nemiroff (MTU) & Jerry Bonnell (USRA): The Medusa Nebula . In: Today's Astronomy Picture of the Day . June 12, 2010. Retrieved July 1, 2010.
↑ ^a ^b T. A. Lozinskaya: Interferometry of the Medusa Nebula A21 (YM 29) . (PDF) In: Soviet Astronomy . June 16, 1973, p. 945. bibcode : 1973SvA .... 16..945L .

[SIMBAD-1] MEDUSA - Planetary Nebula . Center de Données astronomiques de Strasbourg. Retrieved July 1, 2010.

[CUTRI-2] Cutri, RM; Skrutskie, MF; van Dyk, S .; Beichman, CA, et al: 2MASS All Sky Catalog of point sources. . In: The IRSA 2MASS All-Sky Point Source Catalog, NASA / IPAC Infrared Science Archive. . . bibcode : 2003tmc..book ..... C .

[APOD-3] Robert Nemiroff (MTU) & Jerry Bonnell (USRA): The Medusa Nebula . In: Today's Astronomy Picture of the Day . June 12, 2010. Retrieved July 1, 2010.

[LOZINSKAYA-4] T. A. Lozinskaya: Interferometry of the Medusa Nebula A21 (YM 29) . (PDF) In: Soviet Astronomy . June 16, 1973, p. 945. bibcode : 1973SvA .... 16..945L .