Finding supernovae — stars that explode — is a tricky business; a supernova appears as a very bright star for a short period of time, usually between weeks and months. If we’re not looking in the right place at the right time, they’re easy to miss.
Studying the elements that are dispersed when stars explode helps us understand how new star systems are formed, and learn more about the conditions that make life — including ours — possible!
Credit: A. M. Geller/Northwestern University/CTIO/SOAR/NOIRLab/NSF/AURA
But there’s usually no warning for when or where a supernova will appear, so generally they’re found by astronomers who compare images of the same area of sky and look for objects that change in brightness over time.
Credit: Composite by Richard Sword, Institute of Astronomy, University of Cambridge/Gemini Observatory/Isaac Newton Telescope
Not anymore! Rubin Observatory is a great instrument for finding supernovae because it will be scanning the whole southern hemisphere sky at more frequent intervals than any telescope in history.
Credit: NSF–DOE Rubin Observatory/P.J. Assunçao Lago
Rubin Observatory will automatically send out an alert whenever a change is detected in one of its images, and it will take images of the same part of sky every few nights. So a star that has increased in brightness since the last time Rubin Observatory took an image of it will trigger an alert within just a couple of minutes! No other survey has scanned the southern sky quite like this before.
But not all alerts will come from supernovae--there are a lot of other reasons why objects might change in brightness too. So astronomers who study supernovae will visit the website of one of Rubin's "alert brokers," software systems that process and categorize Rubin alerts. There, they'll be able to filter the alerts for the ones most likely to be supernovae.
Watching how a supernova gets brighter, before it reaches its maximum brightness, can reveal fascinating clues about the explosion. So catching them early is important!
Credit: P. Marenfeld and NOIRLab/NSF/AURA
The data set generated by Rubin Observatory over 10 years is expected to contain information about 10 million supernovae. Compare that to the fact that only a few thousand supernovae have been observed to date, and you'll understand why astronomers who study supernovae are so excited about Rubin data!
