Dartmouth Events

Abstract: In this talk, I will present results from two of my recent papers. In Silverberg et al. (2025, AJ, in press), we present the results of an X-ray variability monitoring campaign with XMM-Newton in 2020 and X-ray gratings spectroscopy from Chandra/HETG in 2018. We find that the X-ray spectrum of HL Tau is consistently hot over 31 epochs spanning >20 years, consistent with the temperatures of most Class I YSOs. The high-resolution HETG spectrum indicates the presence of some cooler plasma as well. We find a subset of observations across 20 years of data with significant variability on a 21-day timescale in observed count rate and flux. We discuss the possible origins for this variability, and identify future observations which will better constrain the nature of these changes. In Hyogo et al. (2025, submitted to MNRAS), we investigate SIPS J2045-6332, a nearby brown dwarf identified by the Disk Detective citizen science project (PI Silverberg) as potentially having significant infrared excess, indicative of circumstellar material. Further analysis of SIPS J2045-6332 indicate that an inflated atmosphere due to youth (age 26-200 Myr), with a potential secondary brown dwarf companion. The unique features of SIPS J2045-6332 suggest that further follow-up is necessary for a more full characterization of the system.

Hosted by PhD Student, George Dufrense

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Meeting ID: 974 2079 5665
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