Search Publications
Constraining Atmospheric Composition from the Outflow: Helium Observations Reveal the Fundamental Properties of Two Planets Straddling the Radius Gap
Knutson, Heather A.; Horne, Keith; Collins, Karen A. +13 more
TOI-836 is a ∼2–3 Gyr K dwarf with an inner super Earth (R = 1.7 R⊕, P = 3.8 days) and an outer mini-Neptune (R = 2.6 R⊕, P = 8.6 days). JWST/NIRSpec 2.8–5.2 µm transmission spectra are flat for both planets. We present Keck/NIRSPEC observations of escaping helium for super-Earth b, which shows no excess absorption in t…
Unfolding X-Ray Spectral Data: Conditions and Applications
Huenemoerder, David P.; Gunderson, Sean J.
We present conditions for which X-ray spectra can be "unfolded" to present an accurate representation of the true source spectra. The method we use to unfold the data is implemented in the Interactive Spectral Interpretation Software and distinguishes itself as being model-independent. We find that this method of unfolding makes accurate represent…
Characterizing Superflares in HR 1099 Using Temporal and Spectral Analysis of XMM-Newton Observations
Srivastava, A. K.; Pandey, Jeewan C.; Didel, Shweta
In the present paper, we analyze three energetic X-ray flares from the active RS CVn binary HR 1099 using data obtained from XMM-Newton. The flare duration ranges from 2.8 to 4.1 hr, with e-folding rise and decay times in the range of 27–38 minutes and 1.3–2.4 hr, respectively, indicating rapid rise and slower decay phases. The flare frequency for…
Long-term X-Ray Variability on the Benchmark YSO HL Tau
Schneider, P. C.; Kastner, Joel H.; Principe, David A. +4 more
HL Tau is one of the most well-studied Class I young stellar objects (YSOs), including frequent observations at near- and mid-infrared, (sub)millimeter, and X-ray wavelengths. We present the results of an X-ray variability monitoring campaign with XMM-Newton in 2020 and X-ray grating spectroscopy from Chandra/HETGS in 2018. We find that the X-ray …
AstroSat/UVIT Far- and Near-UV Deep Field Around IC 4329A
Dewangan, Gulab C.; Ganguly, Piyali; Rani, Priyanka
We present high-resolution near-ultraviolet (NUV) and far-ultraviolet (FUV) deep imaging of the field around the Seyfert galaxy IC 4329A based on five observations performed with the Ultra-Violet Imaging Telescope (UVIT) onboard AstroSat. The long exposures of 82.9 ks in the NUV (N245M; λmean = 2447 Å; Δλ = 270 Å) and 92.2 ks in the FUV…