Messier 83

Did You Know?

• M83 is at the center of one of two subgroups within the Centaurus A/M83 Group.
• The galaxies around Centaurus A and those around M83 appear not to be moving relative to each other.
• The two subgroups are sometimes identified as one group and sometimes as two.

Characteristics

M83 is a massive grand design spiral galaxy with a morphological classification of SAB(s)c in the De Vaucouleurs system, indicating a weak-barred spiral with loosely wound arms and no ring. The peculiar dwarf galaxy NGC 5253 lies nearby, and the two likely interacted within the last billion years, triggering starburst activity in their central regions. Star formation occurs preferentially along the leading edge of the spiral arms, consistent with density wave theory. In 2008, NASA's Galaxy Evolution Explorer reported many new stars in the galaxy's outer reaches, where star formation had been thought unlikely. First clues for a possible supermassive black hole at M83's center were published in April 2025.

Supernovae

M83 has hosted six recorded supernovae. The first, SN 1923A, reached magnitude 14 and was spotted by Carl Otto Lampland on May 5, 1923. William Liller found SN 1945B (mag. 14.2) on July 13, 1945. Guillermo Haro discovered SN 1950B (mag. 14.5) on March 15, 1950. Howard S. Gates detected SN 1957D (mag. 15) on December 28, 1957. John C. Bennett observed SN 1968L, a Type II-P event at magnitude 11.9, on July 17, 1968. Robert Evans discovered SN 1983N (mag. 11.9) on July 3, 1983. This supernova made history as the first Type I ever detected in radio, observed with the Very Large Array on July 6. Its spectrum was unusual. Roughly a year after the explosion, a substantial amount of iron was clearly identified in the debris—an unprecedented detection for any supernova. SN 1983N is now the standard example of a hydrogen-deficient Type Ib supernova, with its likely progenitor being a Wolf–Rayet star.