Nearby Young Moving Groups (NYMGs) are loose associations of young stars <150 Myr within ∼120 pc. Among them, the Epsilon Chameleontis Association (eCA) is the youngest group at ∼100 pc with an average age of 5 Myr. Due to these properties, eCA is a prime group to study pre-main sequence stellar evolution, protoplanetary disks, and young exoplanets. To improve statistics on disk fraction, spectral types, age, and early M dwarf evolution, we can identify new members and M dwarfs that belong to the eCA. We utilize the precise astrometry and photometry of Gaia to find new candidate members. Specifically, we will measure the candidates’ positions, motions, and color to assess age and membership. Using 2MASS and WISE photometry, we fit model atmospheres to candidate stars in order to estimate effective temperatures, luminosities, mass, radius, and age, and look for evidence of mid-IR excess from dusty disks. This work resulted in the identification of ∼ 100 new eCA candidates, comprised mainly of M dwarfs and a few proto-brown dwarfs. We present analysis of the optical spectrum of the M-type eCA candidate TOI-1227 and discuss its possible eCA membership, which would make TOI-1227b the youngest known transiting exoplanet. Finally, we present analysis of archival XMM-Newton X-ray spectroscopy for the highly variable eCA star/disk system T Cha.
Astrophysical Sciences and Technology (MS)
Department, Program, or Center
School of Physics and Astronomy (COS)
Varga, Attila, "New and Unique Members of the Epsilon Chamaeleontis Moving Group: A Kinematic and Multi- Wavelength Analysis" (2022). Thesis. Rochester Institute of Technology. Accessed from
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