Week 2

This week focused a lot on reading, but it was extremely helpful. I learned that eclipses aren’t the only thing that cause a star’s brightness to decrease–starspots do, too!

A little bit of background: starpots are darker, cooler regions of the star’s surface. They are the same as sunspots, but on a different star. Cool, right? (Pun intended! But don’t be fooled, they’re still really hot.) Just like the sunpots on our sun, starpots evolve with time. They start small, grow–sometimes taking up a quarter of the star–before shrinking and finally disappearing. They also rotate with the star. A star with a natural variance to it (meaning it increases and decreases in brightness through its own chemistry) will have a curve that looks like a sinusoidal wave where each peak and valley is roughly the same amplitude. With starspots, both the changing size and the changing location show up on the star’s light curve as a sinusoidal wave with increasing and/or decreasing amplitudes.

Here’s an example of an eclipsing binary star that is not variable and does not have visible starspot activity: (Note to self: Figure out how to embed the graphs.)

Here’s an example of an eclipsing binary star that IS variable, but does not have visible starspot activity: (Note to self: Figure out how to embed the graphs.)

Here’s an example of an eclipsing binary star that has visible starspot activity: (Note to self: Figure out how to embed the graphs.)

Pretty cool, huh? And those charts bring me to the second half of what I did this week: I generated light curves! I took the TESS data from 60 stars and generated light curves for them and then I downsampled the data (a new skill!) using Pandas’ Dataframe.sample() function. While I’ve used matplotlib before, this is my first time using Altair and it built these interactive light curves.

That’s all for now, see y’all next week!

Written on June 26, 2020