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arXiv · 1411.5370

Time-monitoring Observations of Br$γ$ Emission from Young Stars

J. A. Eisner·G. H. Rieke·M. J. Rieke·K. M. Flaherty·Jordan M. Stone·T. J. Arnold·S. R. Cortes·E. Cox·C. Hawkins·A. Cole·S. Zajac·A. L. Rudolph
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Abstract

We present multiple epochs of near-IR spectroscopy for a sample of 25 young stars, including T Tauri, Herbig Ae/Be, and FU Ori objects. Using the FSPEC instrument on the Bok 90-inch telescope, we obtained K-band spectra of the BrGamma transition of hydrogen, with a resolution of ~3500. Epochs were taken over a span of >1 year, sampling time-spacings of roughly one day, one month, and one year. The majority of our targets show BrGamma emission, and in some cases these are the first published detections. Time-variability is seen in approximately half of the targets showing BrGamma emission. We compare the observed variability with expectations for rotationally-modulated accretion onto the central stars and time-variable continuum emission or extinction from matter in the inner disk. Our observations are not entirely consistent with models of rotationally-modulated magnetospheric accretion. Further monitoring, over a larger number of epochs, will facilitate more quantitative constraints on variability timescales and amplitudes, and a more conclusive comparison with theoretical models.

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J. A. Eisner, G. H. Rieke, M. J. Rieke, K. M. Flaherty, Jordan M. Stone, T. J. Arnold, S. R. Cortes, E. Cox, C. Hawkins, A. Cole, S. Zajac, A. L. Rudolph. 2014-11-19. Time-monitoring Observations of Br$γ$ Emission from Young Stars. https://doi.org/10.1093/mnras%2Fstu2441

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