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Exploring Gyrochronology with Precise Stellar Characterization

Godoy Rivera, Diego Orlando
http://orcid.org/0000-0003-4556-1277
http://rave.ohiolink.edu/etdc/view?acc_num=osu1626356957292731

Abstract Details

2021, Doctor of Philosophy, Ohio State University, Astronomy.
Rotation plays an important role in the life of stars, and offers a potential diagnostic to infer their ages and that of their planets. The idea of using stellar rotation as a chronometer is known as gyrochronology. While potentially fruitful over a wide range of ages and masses, gyrochronology has not been vetted across all the relevant regimes, and from a theoretical perspective the evolution of rotation is not accurately predicted by stellar models from first principles. For these reasons, empirical studies of rotation play a key role in stellar astrophysics. In recent years, much of the classical knowledge on the rotational evolution of low mass stars has been challenged by new data sets (e.g., Kepler and Gaia). In particular, contemporary results have raised concerns regarding the applicability of gyrochronology as a universal age diagnostic. In this context, this dissertation carries out three efforts to examine gyrochronology in different evolutionary regimes and stellar configurations. Regarding young stars (< 1 Gyr), I illustrate the impact that removing the non-member contamination by using the precise Gaia astrometry has on the rotational sequences of open clusters. The clean and updated sequences show that the overall fraction of rotational outliers decreases considerably but not completely; demonstrate that ground-based rotation periods can be as constraining as space-based periods; illustrate that 1.0 to 0.6 Msun stars populate a global maximum of rotation periods (with potential implications for exoplanet habitability); and suggest evidence that rapid rotators experience a lower torque than intermediate rotators in the saturated domain. Importantly for future calibrations and tests of stellar models, the percentiles of the revised rotational sequences are made publicly available. Regarding old stars (few Gyr), I carry out a search for common proper motion wide binaries in the Kepler field. These systems that can be thought of as the smallest versions of clusters, sharing a common age and chemical composition. When comparing their rotation rates, I find that the component of wide separation binaries have periods that often do not follow the expectations from standard gyrochronology. This result adds to the evidence that spin-down behavior becomes complicated in old systems. Finally, in the context of post main sequence stars, the results from a detailed subgiant characterization study show supporting evidence for the rotation-activity connection beyond the main sequence, and demonstrate that subgiants are ideal targets for precise age and mass determination based on HR diagram location alone. These stars are prime asteroseismic targets for the TESS mission, and will place stringent constraints on angular momentum evolution theories.
Marc Pinsonneault (Advisor)
Jennifer Johnson (Committee Member)
Donald Terndrup (Committee Member)
Matthew Stenzel (Committee Member)
265 p.
Astronomy; Astrophysics
stars; stellar rotation; stellar evolution; star clusters; binary stars

Recommended Citations

Citations

  • Godoy Rivera, D. O. (2021). Exploring Gyrochronology with Precise Stellar Characterization [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1626356957292731

    APA Style (7th edition)

  • Godoy Rivera, Diego. Exploring Gyrochronology with Precise Stellar Characterization. 2021. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1626356957292731.

    MLA Style (8th edition)

  • Godoy Rivera, Diego. "Exploring Gyrochronology with Precise Stellar Characterization." Doctoral dissertation, Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1626356957292731

    Chicago Manual of Style (17th edition)

osu1626356957292731
392
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This open access ETD is published by The Ohio State University and OhioLINK.