Year: 2026
Type: preprint
Abstract: Complex periodic variables (CPVs) are young low-mass stars whose light curves show periodic dips indicative of transiting corotating material. The origin and composition of this material are unclear. Here we present new optical and near-infrared spectroscopy and photometry of four CPVs from Magellan, Keck, Hale, MuSCAT1, MuSCAT2, Tierras, KeplerCam, and TESS. The spectra imply that CPVs host magnetically bound circumstellar plasma clumps, on the basis of sinusoidal-in-time Balmer emission out of transit, and Balmer dimming during transit. Yet large night-to-night changes in circumstellar hydrogen emissivity occur without clear changes in light curve morphology, suggesting that the sharp flux dips are caused not by circumstellar plasma but by dust. Optical chromaticities (depth proportional to $λ^{-β}$, with $β$ = 0.79 $\pm$ 0.16) support this, but the power law breaks in the near-infrared, where a single power law under-predicts the depths observed at 2.1 microns. We therefore favor dips caused by dusty plasma clumps with opaque cores and optically thin halos, though we cannot rule out models in which the dust properties vary per-star or per-epoch. Observations at wavelengths greater than 2 microns and less than 0.4 microns would test this interpretation and clarify the dust's origin.
Source: arXiv (Cornell University)
Authors: Bouma, Luke G., Paolino, Facundo Perez, Hillenbrand, Lynne A., Garcia-Mejia, Juliana, Bieryla, Allyson, Tamburo, Patrick, Charbonneau, David, Livingston, John H., Isogai, Keisuke, Narita, Norio, Fukui, Akihiko, Palle, Enric, Murgas, Felipe, Carvalho, Adolfo S., Isaacson, Howard, Spake, Jessica J., Rebull, Luisa M., Jardine, Moira M., Ciardi, David R., Valenti, Jeff A.
Institutions: California Institute of Technology, Carnegie Institution for Science, Carnegie Observatories, Infrared Processing and Analysis Center, Center for Astrophysics Harvard & Smithsonian, Massachusetts Institute of Technology, Kyoto University, The University of Tokyo, Instituto de Astrofísica de Canarias, Komaba Institute for Science, The University of Tokyo, Universidad de La Laguna, University of California, Berkeley, University of St Andrews, Space Telescope Science Institute
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1129048233, G121809054, G1610079134, G1622782223, G2309174360, G2660406951, G3480869486, G3518538256, G4526231891, G5080475149, G6877667232, G7084143925, G7434936867, 古代説話における諸寺縁起の研究, The Tierras Observatory: An Ultra-precise Time-series Photometer to Characterize Nearby Low-mass Stars and Their Terrestrial Exoplanets, G8688487427, G8971985624, G897484643
OpenAlex ID: W7206192247