| Type Ia supernova, visible from earth — the brightest visible supernova from our perspective in 40 years. The supernova was discovered by the PTF survey on 24 August 2011. The now-exploded star, formerly a white dwarf, is located in Messier 101, the Pinwheel Galaxy, 21 million light years from Earth. As I took this shot, the supernova was nearing the brightness of 2.5 billion suns. Type Ia supernova events occur when a white dwarf star accretes enough additional matter to exceed the Chandrasekhar limit and collapse, triggering runaway fusion and a supernova explosion. Because this collapse happens at a consistent mass, the resulting explosions have very uniform characteristics, and are used as "standard candles" to measure the distance to their host galaxies. #astro #notes EXIF:
| Width: | | 580 |
| Height: | | 387 |
| Company: | | Canon |
| Camera: | | Canon EOS 50D |
| Shot On: | | 2011:09:08 03:18:13 |
| Aperture: | | ƒ/1.8 |
| Focal Length: | | 85.0mm |
| Metering Mode: | | Spot |
| Exposure Mode: | | Manual |
| Flash: | | Did Not Fire |
| Exposure Time: | | 4.0 seconds |
| Exposure Program: | | Manual |
| ISO: | | 3200 |
|
