Refining Kepler Stellar Parameters
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ProtoJeb21
During the last few weeks I've developed a new method for finding pretty accurate mass and radius values for Kepler/K2 stars with transiting planets. You take the transit duration of the planet and manipulate the star's radius and mass values in the Planetary Calculator until you get an orbital period less than 0.01 days off of the actual value. I've done this with many K2 stars (including the now infamous EPIC 212525618), and now I'm doing it with confirmed Kepler planets.
First one up is Kepler-514b. I immediately noticed that the star's size as listed on NASA's Exoplanet Archive was off. Using the mass and radius values given, the planet's duration of 2.92 hours would result in a year of just 1.789 days. However, Kepler-514b has a year of 5.652 days. My calculations show that the most likely size for Kepler-514/KOI-297 is around 0.885 solar radii and 0.945 solar masses - similar in size to EPIC 212525618. Therefore, I predict a temperature of around 5800 Kelvin for this star. These new values would mean that Kepler-514b is a 1.054 Earth radius planet with a temperature around 967 Kelvin. So, it's not as hostile as before, but probably not a very nice place - unless it actually IS a carbon planet (based on its star's very high metallicity) and has a surface covered in diamonds.
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ProtoJeb21
Next planet: Kepler-1646b! I've always liked this one, probably because rocky red dwarf planets are one of my favorite exoplanet class. I quickly figured out that the host star, Kepler-1646, was significantly smaller than 26% the size of our sun. It now appears to be more around 0.1525 solar radii and 0.1725 solar masses. The temperature is likely to be the same. While the star is much smaller and more forgiving to shorter-period planets, Kepler-1646b still is too hot for life with an equilibrium temperature estimated to be around 330 Kelvin. However, due to its smaller size at about 1 Earth radius, it may not have a terrible greenhouse effect.
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