Medusa Nebula

This article is about a planetary nebula. For the Medusa Galaxy Merger, see NGC 4194.

Medusa Nebula
Emission nebula
Planetary nebula
Medusa nebula, Mayall Telescope
Observation data: J2000.0 epoch
Right ascension07h 29m 02.69s[1][2]
Declination+13° 14′ 48.4″[1][2]
Distance1,500 ly (460 pc)[3] ly
Apparent magnitude (V)15.99[1]
Apparent dimensions (V)10.25 x 10.25 arcmin[1]
ConstellationGemini
Physical characteristics
Radius4 [3] ly
Absolute magnitude (V)7.68
Notable featuresVery large & very low surface brightness
DesignationsSharpless 2-274, PK 205+14 1, Abell 21 [1]
See also: Lists of nebulae

The Medusa Nebula is a planetary nebula in the constellation of Gemini. It is also known as Abell 21 and Sharpless 2-274. It was originally discovered in 1955 by University of California, Los Angeles astronomer George O. Abell, who classified it as an old planetary nebula.[4] With the computation of expansion velocities and the thermal character of the radio emission, Soviet astronomers in 1971 concluded that it was most likely a planetary nebula.[4] As the nebula is so large, its surface brightness is very low, with surface magnitudes of between +15.99 and +25 reported.[citation needed]

The central star of the planetary nebula is an PG 1159 star.[5]

  1. ^ a b c d e "MEDUSA – Planetary Nebula". Centre de Données astronomiques de Strasbourg. Retrieved 1 July 2010.
  2. ^ a b Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; Beichman, C. A.; et al. (June 2003). "2MASS All Sky Catalog of point sources". The IRSA 2MASS All-Sky Point Source Catalog, NASA/IPAC Infrared Science Archive. Bibcode:2003tmc..book.....C.
  3. ^ a b Nemiroff, R.; Bonnell, J., eds. (12 June 2010). "The Medusa Nebula". Astronomy Picture of the Day. NASA. Retrieved 1 July 2010.
  4. ^ a b Lozinskaya, T. A. (June 1973). "Interferometry of the Medusa Nebula A21 (YM 29)". Soviet Astronomy. 16: 945. Bibcode:1973SvA....16..945L.
  5. ^ González-Santamaría, I.; Manteiga, M.; Manchado, A.; Ulla, A.; Dafonte, C.; López Varela, P. (2021). "Planetary nebulae in Gaia EDR3: Central star identification, properties, and binarity". Astronomy & Astrophysics. 656: A51. arXiv:2109.12114. Bibcode:2021A&A...656A..51G. doi:10.1051/0004-6361/202141916. S2CID 237940344.