Kepler's Supernova Remnant
Credit
X-ray: NASA/CXC/NCSU/M.Burkey et al; Optical: DSS
This is the remnant of Kepler's supernova, the famous explosion that was discovered by Johannes Kepler in 1604. The red, green and blue colors show low, intermediate and high energy X-rays observed with NASA's Chandra X-ray Observatory, and the star field is from the Digitized Sky Survey.
As reported in our press release,
a new study has used Chandra to identify what triggered this explosion.
It had already been shown that the type of explosion was a so-called
Type Ia supernova, the thermonuclear explosion of a white dwarf star.
These supernovas are important cosmic distance markers for tracking the accelerated expansion of the Universe.
However, there is an ongoing controversy about Type Ia supernovas. Are they caused by a white dwarf pulling so much material from a companion star that it becomes unstable and explodes? Or do they result from the merger of two white dwarfs?
The new Chandra analysis shows that the Kepler supernova was
triggered by an interaction between a white dwarf and a red giant star.
The crucial evidence from Chandra was a disk-shaped structure near the
center of the remnant. The researchers interpret this X-ray emission to
be caused by the collision between supernova debris and disk-shaped
material that the giant star expelled before the explosion. Another
possibility was that the structure is just debris from the explosion.
The disk structure seen by Chandra in X-rays is very similar in both
shape and location to one observed in the infrared by the Spitzer Space
Telescope. This composite image shows Spitzer data in pink and Chandra
data from iron emission in blue. The disk structure is identified with a
label.
X-ray Image (Elements)
This composite figure also shows a remarkably large and puzzling concentration of iron
on one side of the center of the remnant but not the other. The authors
speculate that the cause of this asymmetry might be the "shadow" in
iron that was cast by the companion star, which blocked the ejection of
material. Previously, theoretical work has suggested this shadowing is
possible for Type Ia supernova remnants.
The authors also produced a video showing a simulation
of the supernova explosion as it interacts with material expelled by
the giant star companion. It was assumed that the bulk of this material
was expelled in a disk-like structure, with a gas density that is ten
times higher at the equator, running from left to right, than at the
poles. This simulation was performed in two dimensions and then
projected into three dimensions to give an image that can be compared with observations. The good agreement with observations supports their interpretation of the data.
These results were published online and in the February 10th, 2013 issue of The Astrophysical Journal.
Fast Facts for Kepler's Supernova Remnant:
Scale: Image is 12 arcmin across (45 light years)
Category: Supernovas & Supernova Remnants
Coordinates (J2000): RA 17h 30m 40.80s | Dec -21° 29' 11.00"
Constellation: Ophiuchus
Observation Date: 6 pointings between April and July, 2006
Observation Time: 205 hours 50 min (8 days 13 hours 50 min)
Obs. ID: 6714-6718, 7366
Instrument: ACIS
Also Known As: SN 1604, G004.5+06.8, V 843 Ophiuchi
References: Burkey, M.T. et al, 2013, ApJ, 764, 63; arXiv:1212.4534
Color Code: X-ray (Red, Green, Blue); Optical (Grayscale)
