Monthly Exoplanet Paper Roundup: Circumbinaries, Quantum Chemistry, Wide-Orbit Giants, and April Fools’

Hi folks! I wanted to start a new feature to get me back on track of blogging more frequently, so I’m introducing a monthly series about exoplanet papers that I found interesting. The plan is to post on the last Monday of every month to point out papers were particularly intriguing and spotlight one or maybe two for a more in-depth description (although not this month for the in-depth ones). I hope this will help you connect with some new exoplanet science that you find interesting!

Note that all links are to arXiv papers, which are free and available to the public. You can also follow links from arXiv to the peer-reviewed, published versions when available.

Quick Bites

I’m going to try to limit myself to about 5 papers, which is harder than it might sound. An arXiv search for papers with the word “planet” in the abstract from the last month in the astro-ph section returns 160 results!

Discovery of a Third Transiting Planet in the Kepler-47 Circumbinary System (Orosz et al.): Circumbinary planets are a really interesting set of planets that are orbiting both of the stars in a binary system—think Tattoine. We only know of 9 such systems, and Kepler-47 is the only one that has multiple planets. There were two known previously, and this paper announces the discovery of a third planet that is orbiting in between the two known planets.

The binary mass ratios of circumbinary planet hosts (Martin): Speaking of circumbinary planets, my UChicago colleague here examines how the mass ratio of the binary biases transits of circumbinary planets. There are several competing effects, but surprisingly they tend to cancel one another out, and so the transit detections are essentially unbiased.

Impacts of Quantum Chemistry Calculations on Exoplanetary Science, Planetary Astronomy, and Astrophysics (Kao et al.): This is a white paper written for the Astro 2020 Decadal Survey on Astronomy and Astrophysics. I’m including this one because it illustrates some of the non-research paper content that can be found on arXiv as well as the incredibly interdisciplinary nature of the exoplanets field. Quantum chemistry? Yep, that matters!

On the Mass Function, Multiplicity, and Origins of Wide-Orbit Giant Planets (Wagner et al.): Direct imaging is a great technique for observing wide-orbit planets, but it’s very biased towards young, massive planets. The authors here use survival analysis statistics on the currently-detected population of wide-orbit giant planets to predict an underlying relative mass function. They find that the mass distribution rises a lot for lower masses (aka more like planets, less like brown dwarfs) and that there are a lot of less-massive companions out there waiting to be imaged in future surveys.

The Long Night: Modeling the Climate of Westeros (Paradise et al.): Yes, you read that right! This month happens to encompass April 1, which means a chance for scientists to let loose and publish some perhaps oddball papers. A previous April 1 paper (Freistetter & Grützbauch 2018) had provided a possible orbital solution to explain the strange Westerosi seasons, a very unique case called a Sitnikov orbit. This paper applies a 3-D global climate model to a Sitnikov-orbiting Westeros, and they find—well, no spoilers, but it might involve the Children of the Forest constructing orbital megastructures…