Kepler's Supernova

Illustration from Johannes Kepler's book De Stella Nova in Pede Serpentarii indicating the location of the 1604 supernova, marked with an N on the right foot of the Ophiuchus constellation. 

Supernova SN 1604, also known as Kepler's Supernova, Kepler's Nova or Kepler's Star, in the constellation Ophiuchus, was first seen by observers in northern Italy on the evening of October 9, 1604, and far eastern (Chinese and Korean) within days thereafter.
 
   Visible to the naked eye, Kepler's Star was brighter at its peak than any other star in the night sky, with an apparent magnitude of −2.5. It was visible during the day for over three weeks and remained visible to the naked eye for 18 months. Records of its sighting exist in European, Chinese, Korean, and Arabic sources. It was the second supernova to be observed in a generation (after SN 1572 seen by Tycho Brahe in Cassiopeia) and is the most recent supernova in the Mily Way observed by the naked eye. The supernova was named after Johannes Kepler, even though he was not its first observer, as his observations tracked the object for an entire year. These observations were described in his book De Stella nova in pede Serpentarii ("On the new star in Ophiuchus's foot", Prague 1606).

   SN 1604 was a Type Ia supernova. This class of supernovas occurs when a white dwarf gains mass, either by pulling gas off a companion star or merging with another white dwarf, until it becomes unstable and is destroyed by a thermonuclear explosion. A dim nebula was discovered in 1941 at the Mount Wilson Observatory with a brightness of 19 mag which is the supernova remnant of SN 1604. Only filaments can be seen in visible light. It is however a strong radio source. Its diameter is 4 arc min. Its distance is not well determined but is between 3 and more than 7 kiloparsecs (10,000 to 23,000 lightyears).

A composite image of the remnant of Kepler’s Supernova. The X-rays, observed by the Chandra X-ray Observatory, are shown in five colors from lower to higher energies: red, yellow, green, blue, and purple. An optical image from the Digitized Sky Survey shows stars in the field.
Credit: X-ray: NASA/CXC/NCSU/M.Burkey et al; Optical: DSS 

A false-color composite image of the supernova remnant nebula from SN 1604. This combined image - from NASA's Spitzer Space Telescope, Hubble Space Telescope, and Chandra X-ray Observatory - unveils a bubble-shaped shroud of gas and dust that is 14 light-years wide and is expanding at 2,000 kilometers per second. Observations from each telescope highlight distinct features of the supernova remnant, a fast-moving shell of iron-rich material from the exploded star, surrounded by an expanding shock wave that is sweeping up interstellar gas and dust.
   Color code (energy):
Blue: X-ray (4-6 keV), Chandra X-ray Observatory, the higher-energy X-rays come primarily from the regions directly behind the shock front.
Green: X-ray (0.3-1.4 keV), Chandra X-ray Observatory; lower-energy X-rays mark the location of the hot remains of the exploded star.
Yellow: Optical, Hubble Space Telescope; the optical image reveals 10,000 degrees Celsius gas where the supernova shock wave is slamming into the densest regions of surrounding gas.
Red: Infrared, Spitzer Space Telescope; the infrared image highlights microscopic dust particles swept up and heated by the supernova shock wave.
Credit: NASA/ESA/JHU/R.Sankrit & W.Blair

 

© 2025, Andrew Mirecki