Marius Hartig & Felix Kalb
In this Experiment of the advanced lab course, our goal was to observe the transit of an exoplanet in front of a star. The exoplanet we chose to observe and analyze is K2-30b. The observation took place on the 24th of January in 2024 and we used the refractor telescope of the TURMX observatory in Extremadura.
Sadly the conditions for the observation weren’t ideal for the observation because the sky was slightly clouded. This didn’t hinder us at taking 128 pictures over 4 hours with a shutter speed of 120s. Because the telescope is mounted and corrects the spin of the earth, one gets sharp pictures of the stars and not the star trails one would get exposed for this long with a normal camera on a tripod. These pictures were then imported into Muniwin, which did the aperture and the differential photometry for us, and we could export and analyze the data, which is because of the conditions quite
noisy. . Despite that, it was possible to fit a trapezoid function to the points. This was done with mathematica and with the extracted fit parameters astrophysical parameters of the exoplanet could be determined.
It was found,that K2-30b has a radius of 1.13(9) RJ and the orbit radius is about 0.050(11) AU. The determination of the mass wasn’t successful as the mass was determined to be 104(670) MJ, while the known catalogue value is 0.579(28) MJ. This deviation is caused by the method we used to calculate the mass and to get a better result another method should have been used. The uncertainties for the other two values are okay and caused by the noise in the measurement data, which is normal in photometric measurements and could be much worse. The value for the radius of K2-30b and the
orbit of this exoplanet were near the catalogue values and it’s quite astonishing that these results could be gained in these observing conditions using this equipment.
