Emma Molden



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We researched radio astronomical data from the star Omicron Ceti, more commonly known as Mira, to determine if there is evidence for orbiting planets. There is a variation in the silicon monoxide maser radial velocity of Mira that could have been due to the effect of orbiting planets. We analyzed the radial velocity data collected from Mira over the past forty years. The data were examined for periodicities. A periodicity refers to a repeating pattern within the data. Three possible frequencies were found. Each frequency within the star had the potential to be a pattern caused by an orbiting planet. The three frequencies were approximated with three sine waves. The radial velocity versus time was fit with a curve that was the sum of the three sine waves. The amplitudes of the fit sine waves model the change in velocity centroid of Mira possibly due to orbiting planets. From the wave amplitudes the masses of the suspected planets were estimated. If the periodicities of Mira were caused by orbiting planets, two of the “planets” would be about one twentieth the mass of Mira and the other “planet” would be about one fifth the mass of Mira. The amplitudes of the three fit sine waves are too large to be caused by orbiting planets. The changes in the velocity of Mira are probably due to periodicities within the star.

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Planetary theory


Astrophysics and Astronomy

Using the Radial Velocity to Search for Orbiting Planets Around Mira