The Misaligned Orbit of the Earth-sized Planet Kepler-408b

Shoya Kamiaka, Othman Benomar, Yasushi Suto, Fei Dai, Kento Masuda, Joshua N. Winn

Research output: Contribution to journalArticlepeer-review


Kepler-408 is one of the 33 planet-hosting Kepler stars for which asteroseismology has been used to investigate the orientation of the stellar rotation axis relative to the planetary orbital plane. The transiting hot Earth, Kepler-408b, has an orbital period of 2.5 days and a radius of 0.86 R , making it much smaller than the planets for which spin-orbit alignment has been studied using the Rossiter-McLaughlin effect. Because conflicting asteroseismic results have been reported in the literature, we undertake a thorough re-appraisal of this system and perform numerous checks for consistency and robustness. We find that the conflicting results are due to the different models for the low-frequency noise in the power spectrum. A careful treatment of the background noise resolves these conflicts, and shows that the stellar inclination is i∗ = 42+5 -4 degrees. Kepler-408b is, by far, the smallest planet known to have a significantly misaligned orbit.

Original languageEnglish (US)
Article number137
JournalAstronomical Journal
Issue number4
StatePublished - Apr 2019


  • asteroseismology
  • methods: data analysis
  • planetary systems
  • stars: oscillations
  • stars: rotation
  • techniques: photometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'The Misaligned Orbit of the Earth-sized Planet Kepler-408b'. Together they form a unique fingerprint.

Cite this