|Designation|| SN 1604|
|Right ascension||17h 30m 41.5s|
|Declination||-21° 29′ 31.2″|
|Type of object||Supernova|
|Dimensions||5.0 x 5.0 arcminutes|
|Magnitude|| Apparent Mag: -2.5 (peak)|
Absolute Mag: -15.5
|Distance from Earth||13,000 ly|
Kepler's supernova (SN 1604, G4.5+6.8) was a supernova that took place in the constellation of Ophiuchus. Today, there is a supernova remnant visible in its location. The supernova is named after Johannes Kepler who was one of the first people to observe it and is the last known supernova to have occurred in the Milky Way.
The supernova was discovered simultaneously by several people on October 9, 1604 where it appears as a more luminous star than any other in the sky. Jan Brunowski saw the supernova and informed Kepler. The reason so many people saw the supernova is likely due to the conjunction of the planets Mars, Jupiter and Saturn that took place on this day. Kepler first observed the object a week later on October 17 due to bad weather and, inspired by Tycho Brahe's investigations of the earlier supernova SN 1572, began studying it. The supernova was approximately the same brightness as Mars and after a matter of days was brighter than Jupiter. It stopped being visible to the naked eye in November of that year but reemerged in January 1605 where it was brighter than the star Antares. Kepler continued his observations until March 1606 when it became invisible. The supernova was visible for around 18 months. Like Tycho's supernova, it was evidence that the stars were not mutable.
Later in 1941, astronomers utilised the Mount Wilson Observatory's 100 inch telescope to identify the remnant. Then in 1943, Walter Baade used the measurements taken by Kepler and Johannes Fabricius to determine the light curve for the supernova, a plot of how its brightness varied over time. He determined it was likely a Type I supernova and have a peak magnitude of -2.2.
Properties and Structure
Situated in the constellation of Ophiuchus, the nebula is thought to be located some 13,000 light years away. This makes the remnant's apparent size of 5.0 x 5.0 arcminutes correspond to a physical size of around 14 ly. The nebula is expanding rapdily at 2,000 km/s. It is believed the nebula reached a peak apparent star magnitude of -2.2. Today the nebula has a magnitude of +19. The supernova created a shockwave, the effects of which can be seen in the remaining nebula today.
The remnant has been studied using NASA's Hubble Space Telescope, X-ray observatory and its Spitzer space telescope. The x-ray data collected by Chandra has revealed areas containing very energetic particles and extremely hot gas. It is thought these x-rays are generated by high energy electrons. These were created by the shockwave the supernova produced. Lower energy x-rays are also emitted from a shell in the heart of the nebula.
Observations in the optical regions of the electromagnetic spectrum have revealed where the shockwave hits high density regions of gas. After the shock wave passes, these denser regions form bright knots and filaments. Infrared images of the nebula have shown microscopic dust particles that have been heated by the shockwave and brightest where in the knots and filaments.
- Composite View of Kepler's Supernova Remnant - SN 1604 from spitzer.caltech.edu
- SN 1604, Kepler's Supernova from messier.seds.org
- From definition of absolute magnitude, using apparent magnitude (-2.5) and distance (13,000 ly) given here.
- Kepler's supernova from britannica.com
- Vink J. (2016) Supernova 1604, Kepler’s Supernova, and Its Remnant. In: Alsabti A., Murdin P. (eds) Handbook of Supernovae. Springer, Cham. On ArXiv
- Baade, W. (1942) "Nova Ophiuchi of 1604 as a Supernova.," Astrophysical Journal, vol. 97, p.119. On the Astronomy Abstract Service