From the January 2024 issue

Simeis 147

By | Published: January 1, 2024

Take one look at supernova remnant Simeis 147 and you’ll immediately know why it’s called the Spaghetti Nebula. It lies in Taurus the Bull, near that constellation’s northern border with Auriga. In fact, its position is about 6° north of an even more famous supernova remnant, the Crab Nebula (M1).

A team of Russian astronomers led by G.A. Shajn and V.E. Hase, working at the Crimean Astrophysical Observatory, discovered Simeis 147 in 1952. The camera they used had a field of view of nearly 3°, and the nebula filled all of it. That would make its apparent diameter six times greater than that of the Full Moon. Because it is so huge, it’s not possible to see the entire nebula visually. Amateur astronomers with access to a 20-inch or larger telescope, a dark site with terrific seeing (atmospheric steadiness), and an Oxygen-III filter might glimpse some brighter regions at its southern edge. Astroimagers with wide-field camera setups, however, can capture striking pictures of it with relative ease.

Another catalog identifier you might encounter is Sharpless 2–240. American astronomer Steward Sharpless found it on photographic plates of the Palomar Observatory Sky Survey. He published his second catalog, which contained 313 such objects, in 1959. Simeis 147 was the 240th entry.

Current estimates place the supernova remnant at a distance of some 3,000 light-years. If that’s correct, the diameter of the Spaghetti Nebula would be about 160 light-years.

Researchers think the explosion of the supergiant star that created this object happened approximately 40,000 years ago. The core of that star is now a pulsar (a rapidly rotating neutron star) designated PSR J0538+2817. Radio astronomers have detected the large amount of radio radiation that the object produces.