I've been getting lots of Qs about why manganese is gr8!

(jk no one has actually asked me about this, I just want to write about it)

Here's part 1, which will cover some basics for non-astro folks! (Part 2 will actually go into details about why manganese is cool.) A thread: https://twitter.com/MiaDoesAstro/status/1289027180144365568

1) A big question in astronomy is: where did all the elements come from? For astronomers who spend time thinking about this question, manganese (Mn) is classified as an "iron-peak" element, because it's near iron (Fe) on the periodic table:

2) Note the colors in the periodic table in the last tweet! (Credit to @jajohnson51 for making it!) The colors indicate the astrophysical sources that make each element. Ex: iron-peak elements are produced by a combination of "exploding massive stars" and "exploding white dwarfs"

3) Why "iron-peak"? Iron is the heaviest element that stars can make through normal stellar fusion. This is because for light elements, stars can *get* energy by fusing elements into heavier ones. But it *takes* energy to fuse anything heavier than Fe:

4) This is why supermassive stars go supernova! Once they run out of hydrogen to fuse, they fuse heavier elements... until they hit iron. Then they have no energy to hold them up against gravity, and they collapse and explode! Here's an X-ray/optical image of a supernova remnant:

5) So some amount of iron-peak elements get made in these supermassive stars... but there just aren't that many of these big bois. Most stars are like our Sun, which isn't massive enough to fuse heavier elements, & will run out of usable fuel once it hits carbon and oxygen.

6) Don't worry, the Sun has another 5 billion years to go before it runs out of hydrogen! At that point it will swell up into a red giant (artist conception shown in GIF, higher def video here: https://www.eso.org/public/videos/eso1919c/) and leave behind a dense core, called a "white dwarf"

7) Some white dwarfs can also go supernova! This happens when temperature/pressure in the white dwarf gets high enough to set off a runaway nuclear reaction, which leads to the whole star exploding in what's called a Type Ia supernova! Here's an X-ray/optical image of a remnant:

8) This runaway nuclear reaction creates SUPER high temperatures and pressures, perfect conditions for fusion reactions. And as we know, the iron-peak elements are super easy to produce, since making them *gives* energy. So Type Ia supernovae make a lot of them!

8) Type Ia supernovae are esp cool because many of them give off the same* amount of light, so they can be used to measure distances.

*not quite the same, but they do show similar patterns in brightness over time & can be "standardized" (image from @claudiascosmos' 2009 paper)

9) It's like using 2 candles that are the same brightness but at different distances—since they're giving off the same amount of light, you can tell how far away they are based on how bright they *look*. This method was used to discover the accelerating expansion of the universe!

10) Except we don't fully understand how Type Ia supernovae actually work. It seems like there are multiple "channels" with different masses, different explosion mechanisms, and even different numbers of white dwarfs involved... But we don't know which channel contributes *most*.

11) This question—what the heck are Type Ia supernovae?—is the focus of a lot of active research in astro!

And in Part 2 (coming soon to a twitter feed near you), I'll explain why manganese (of which you should be a fan-ganese) can help us address this question.