The Medusa Nebula is a

planetary nebula A planetary nebula (PN, plural PNe) is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The term "planetary nebula" is a misnomer because they are unrelated to ...

in the constellation of

Gemini Gemini may refer to: Space * Gemini (constellation), one of the constellations of the zodiac ** Gemini in Chinese astronomy * Project Gemini, the second U.S. crewed spaceflight program * Gemini Observatory, consisting of telescopes in the Northern ...

. It is also known as

Abell Abell may refer to: People * Abell (surname) *George O. Abell, of the astronomical catalogues fame Places ;United States * Abell, Maryland, a location in St. Mary's County, Maryland * Abell, a neighborhood in Baltimore, Maryland * Abells Corne ...

21 and Sharpless 2-274. It was originally discovered in 1955 by

University of California, Los Angeles The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California St ...

astronomer

George O. Abell George Ogden Abell (March 1, 1927 – October 7, 1983) was an American educator. Teaching at University of California, Los Angeles, UCLA, priorly he worked as a research astronomer, administrator, as a popularizer of science and of education, and ...

, who classified it as an old planetary nebula. Until the early 1970s, the nebula was thought to be a

supernova remnant A supernova remnant (SNR) is the structure resulting from the explosion of a star in a supernova. The supernova remnant is bounded by an expanding shock wave, and consists of ejected material expanding from the explosion, and the interstellar mat ...

. 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. As the nebula is so large, its surface brightness is very low, with surface magnitudes of between +15.99 and +25 reported. The central star of the planetary nebula is an

PG 1159 star A PG 1159 star, often also called a pre-degenerate, is a star with a hydrogen-deficient atmosphere that is in transition between being the central star of a planetary nebula and being a hot white dwarf. These stars are hot, with surface temperatur ...

References

External links

*The Sharpless Catalog
Sharpless 274
*

APOD Astronomy Picture of the Day (APOD) is a website provided by NASA and Michigan Technological University (MTU). According to the website, "Each day a different image or photograph of our universe is featured, along with a brief explanation written ...

picture
The Medusa Nebula
*Images of the Universe

Planetary nebulae Gemini (constellation) Sharpless objects 21 Astronomical objects discovered in 1955 {{nebula-stub

See also

References

External links