G1.9+0.3 is the youngest known supernova remnant in the Milky Way, a small expanding shell near the Galactic Centre whose explosion no one saw.
At a glance
| type | supernova remnant |
|---|---|
| distance from the Sun | 27,700 light-years (8.5 kpc) |
| its light left it | 27,700 years ago |
| size in the piece | about 9.8 light-years acrossmodel |
Read off the piece’s own catalogue, the same values it draws with. Model marks a property of the piece’s galaxy model rather than a measurement.
About G1.9+0.3
Its name is simply its position in galactic coordinates. It lies toward the Galactic Centre, where the dust is so thick that the explosion, which in our sky happened only in the age of photography, was completely hidden in visible light.
Its youth was established by comparing radio images with later X-ray images from Chandra: the shell had grown measurably larger in between, and working backward gave a very young age. Its X-ray spectrum and fast expansion point to a thermonuclear explosion of a white dwarf.
It is the only Galactic remnant whose shell is seen to brighten in radio as it grows, a sign of a blast wave still young enough to be accelerating particles ever more strongly.
What you see in the piece
It is drawn as a small hollow shell far off near the Galactic Centre, invisible in visible light behind the dust; look for it in the radio band.
Measured or modelled
Its age is inferred from its expansion and its distance is assumed close to that of the Galactic Centre. The drawn extent is modelled.
Questions
What is the youngest supernova remnant in the Milky Way?
G1.9+0.3 is the youngest known. Its explosion was hidden from view by dust near the Galactic Centre, and its youth was found from how fast its shell is growing.
How far away is G1.9+0.3?
G1.9+0.3 is about 27,700 light-years (8.5 kpc) from the Sun, near the centre of the Galaxy.