Search Publications
Unusual Isotopic Abundances in a Fully Convective Stellar Binary
Mills, E. A. C.; Crossfield, I. J. M.; Lothringer, J. D. +6 more
Low-mass M dwarfs represent the most common outcome of star formation, but their complex emergent spectra hinder detailed studies of their composition and initial formation. The measurement of isotopic ratios is a key tool that has been used to unlock the formation of our solar system, the Sun, and the nuclear processes within more massive stars. …
The Duration of Star Formation in Galactic Giant Molecular Clouds. I. The Great Nebula in Carina
Povich, Matthew S.; Nuñez, Evan Haze; Robitaille, Thomas P. +1 more
We present a novel infrared spectral energy distribution (SED) modeling methodology that uses likelihood-based weighting of the model fitting results to construct probabilistic Hertzsprung-Russell diagrams (pHRD) for X-ray-identified, intermediate-mass (2-8 M ⊙), pre-main-sequence young stellar populations. This methodology is designed …
High-fidelity Imaging of the Inner AU Mic Debris Disk: Evidence of Differential Wind Sculpting?
Stark, Christopher C.; Kowalski, Adam F.; Davenport, James R. A. +17 more
We present new high-fidelity optical coronagraphic imagery of the inner ∼50 au of AU Mic’s edge-on debris disk using the BAR5 occulter of the Hubble Space Telescope Imaging Spectrograph (HST/STIS) obtained on 2018 July 26-27. This new imagery reveals that “feature A,” residing at a projected stellocentric separation of 14.2 au on the southeast sid…
Hubble Space Telescope Emission-line Images of Nearby 3CR Radio Galaxies: Two Photoionization, Accretion, and Feedback Modes
Sparks, William B.; Chiaberge, Marco; Capetti, Alessandro +3 more
We present HST/ACS narrowband images of a low-z sample of 19 3C radio galaxies to study the Hα and [O III] emissions from the narrow-line region. Based on nuclear emission-line ratios, we divide the sample into high- and low-excitation galaxies (HEGs and LEGs). We observe different line morphologies, extended [O III] emission, large [O III]/Hα sca…
A Search for Water Vapor Plumes on Europa using SOFIA
Sparks, W. B.; Dello Russo, N.; Hand, K. P. +8 more
We present mid-infrared Stratospheric Observatory for Infrared Astronomy (SOFIA)/Echelon Cross Echelle Spectrograph (EXES) spectroscopy of Europa, seeking direct evidence of the presence of water vapor arising from plumes venting from the surface. We place quantitatively useful upper limits on the strength of water vibrational-rotational emission …
Genus Statistic Applied to the X-Ray Remnant of SN 1572: Clues to the Clumpy Ejecta Structure of Type Ia Supernovae
Sato, Toshiki; Hughes, John P.; Williams, Brian J. +1 more
Clumpy structures are a common feature in X-ray images of young Type Ia supernova remnants (SNRs). Although the precise origin of such clumps remains unclear, there are three generic possibilities: clumpiness imposed during the explosion, hydrodynamic instabilities that act during the remnant’s evolution, and preexisting structures in the ambient …
A Comparison of the X-Ray Properties of FU Ori-type Stars to Generic Young Stellar Objects
Hillenbrand, Lynne A.; Kuhn, Michael A.
Like other young stellar objects (YSOs), FU Ori-type stars have been detected as strong X-ray emitters. However, little is known about how the outbursts of these stars affect their X-ray properties. We assemble available X-ray data from XMM-Newton and Chandra observations of 16 FU Ori stars, including a new XMM-Newton observation of Gaia 17bpi dur…
Constraints on the Galactic Inner Halo Assembly History from the Age Gradient of Blue Horizontal-branch Stars
Whitten, Devin D.; Beers, Timothy C.; Placco, Vinicius M. +6 more
We present an analysis of the relative age distribution of the Milky Way halo, based on samples of blue horizontal-branch (BHB) stars obtained from the Panoramic Survey Telescope and Rapid Response System and Galaxy Evolution Explorer photometry, as well a Sloan Digital Sky Survey spectroscopic sample. A machine-learning approach to the selection …
TOI-150: A Transiting Hot Jupiter in the TESS Southern CVZ
Butler, R. Paul; Schneider, Donald P.; Kollmeier, Juna A. +24 more
We report the detection of a hot Jupiter ({M}p={1.75}-0.17+0.14 {M}{{J}}, R p = 1.38 ± 0.04 R J) orbiting a middle-aged star ({log}g={4.152}-0.043+0.030) in the Transiting Exoplanet Survey Satellite (TESS) southern continuous viewing zone (β = -79.°59). We co…
A BCG with Offset Cooling: Is the AGN Feedback Cycle Broken in A2495?
Gastaldello, F.; Ettori, S.; Amblard, A. +6 more
We present a combined radio/X-ray analysis of the poorly studied galaxy cluster A2495 (z = 0.07923) based on new EVLA and Chandra data. We also analyze and discuss Hα emission and optical continuum data retrieved from the literature. We find an offset of ∼6 kpc between the cluster brightest cluster galaxy (BCG) (MCG+02-58-021) and the peak of the …