Simeis 147

{{Short description|Supernova remnant in the Milky Way}}

{{Use dmy dates|date=January 2020}}

{{ Infobox supernova |

| name = Simeis 147

| image = File:S147 SH2-240 GeorgesAttard Apod1012020.jpg

| caption= The supernova remnant nebula from Simeis 147 or the Spaghetti Nebula.

| epoch = J2000

| type = Unknown

| SNRtype = Mixed-morphology

| host = Milky way

| constellation = Taurus

| ra = {{RA|05|39|06}}

| dec = {{DEC|+27|59|55}}

| gal = Unknown

| discovery = 1952{{cite web|title=Simeis 147, Supernova Remnant in Taurus|url=http://www.astropix.com/HTML/SHOW_DIG/Simeis147_Supernova_Remnant.HTM|date=28 February 2013|publisher=AstroPix}}

| iauc =

| mag_v = 6.5

| distance = {{convert|3000|ly|kpc|lk=on}}

| progenitor = Unknown

| progenitor_type = Unknown

| b-v = Unknown

| notes =

}}

Simeis 147, also known as the Spaghetti Nebula, SNR G180.0-01.7 or Sharpless 2-240, is a supernova remnant (SNR) in the Milky Way, straddling the border between the constellations Auriga and Taurus. It was discovered in 1952 at the Crimean Astrophysical Observatory by Grigory Shajn and his team using a Schmidt camera and a narrowband filter close to the Hydrogen Alpha transmission line. It is difficult to observe due to its extremely low surface brightness. This discovery was part of a survey conducted between 1945 and 1955, most likely using captured German equipment, as the observatory was practically destroyed during WWII. The Schmidt camera had a field of view of 175'. Many previously unknown hydrogen nebula were discovered this way, as they are not readily visible in regular photographs.

The nebulous area has an almost spherical shell and a filamentary structure.{{cite web|title=VizieR query result|url=http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ52b391ab3a6e&-out.add=.&-source=VII/20/catalog&recno=240|date=20 December 2013|publisher=Centre de Données astronomiques de Strasbourg}} The remnant has an apparent diameter of approximately 3 degrees, an estimated distance of approximately 3000 (±350) light-years, and an age of approximately 40,000 years.{{Cite APOD|title=Simeis 147: Supernova Remnant|date=9 October 2012}} At that distance, it spans roughly 160 lightyears.

It is believed that the stellar explosion left behind a rapidly spinning neutron star known as pulsar PSR J0538+2817 in the nebula core, emitting a strong radio signal.{{cite simbad|title=SNR G180.0–01.7|access-date=20 December 2013}}