Statistical arguments are how we understand a remarkable number of things in astronomy. Let’s face it, the sky is big, daylight and clouds happen, and we just can’t watch everything, everywhere, all of the time. Instead, we’ll observe where we can, when we can, and then we use statistics to figure out how common different things may be.
A new paper in The Astrophysical Journal with first author Kishalay De documents how a new team used the Palomar telescope to look for novae — the bright explosions of material falling onto a white dwarf from a companion star. With careful statistics, they were able to jump from the number of novae detected in their images to the number of novae taking place in our galaxy each year. By accounting for how much of the galaxy is blocked by dust and how much of the sky was and was not observed, they estimated that 46 +/- 13 novae go off in our galaxy every year.
While not entirely exciting on its own, this research is going to do a lot to help astronomers model the chemical evolution of galaxies. Each of the novae transforms material from one set of simple atoms to a more complicated set of atoms, and these atoms are the ones needed to form planets, plants, and people. By better understanding the nova rate, we can better understand the chemical evolution rate and eventually the planet-forming rate.
Science News article
“A population of heavily reddened, optically missed novae from Palomar Gattini-IR: Constraints on the Galactic nova rate,” Kishalay De et al., submitted to The Astrophysical Journal (preprint on arxiv.org)