The search for exoplanets has been a fascinating journey ever since the Kepler Space Telescope began its mission in 2009. One of the most intriguing discoveries made by Kepler is the consistent rhythm in the orbits of alien worlds. Typically, if one planet takes twice as long to orbit its star as the planet before it, the next planet should follow the same pattern. However, there are a few planetary systems that do not adhere to this “peas-in-a-pod” rule.
Recently, at the American Astronomical Society’s 247th meeting in Phoenix, Federico Noguer, an undergraduate at Arizona State University, shared a particularly curious exception to this trend. The star TOI-1873, located approximately 600 light-years from Earth, hosts three large planets similar in size to Neptune. These planets were discovered using data from the Transiting Exoplanet Survey Satellite (TESS), with two of them initially spotted through a citizen science project called Planet Hunters TESS.
The innermost planets in the TOI-1873 system have orbital periods of about seven and 25 days, suggesting that each planet’s orbit should be approximately 3.6 times longer than its predecessor. As a result, the third planet was expected to complete a revolution around the star every 90 days. However, an astonishing 900 days passed between each observation of the third planet by TESS.
It is possible that TESS missed some of the third planet’s flybys, indicating a shorter but still significant orbital period. Molly Simon, an astronomer at ASU, acknowledges the unusual nature of this spacing and emphasizes the need for further observations to unravel the mysteries of this star system.
The research team has already determined the masses of the inner two planets and confirmed them as exoplanets. However, they are eager to investigate the orbit of the elusive third planet. By securing time at ground-based observatories, they hope to shed light on the peculiar characteristics of this distant solar system.
Crowdsourced science has played a crucial role in uncovering anomalies like the one observed in the TOI-1873 system. Courtney Dressing, an astronomer at the University of California, Berkeley, emphasizes the significance of public participation in scientific discoveries.
As scientists continue to gather data and analyze the TOI-1873 system, they are exploring various hypotheses to explain its unique configuration. Possible explanations include the presence of hidden planets or interactions with other celestial bodies that influenced the planets’ orbits. A paper confirming the discovery of this intriguing solar system is expected to be submitted for publication later this year.
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