Search Publications
TESS Asteroseismology of β Hydri: A Subgiant with a Born-again Dynamo
Stassun, Keivan G.; Metcalfe, Travis S.; van Saders, Jennifer L. +12 more
The solar-type subgiant β Hyi has long been studied as an old analog of the Sun. Although the rotation period has never been measured directly, it was estimated to be near 27 days. As a Southern Hemisphere target, it was not monitored by long-term stellar activity surveys, but archival International Ultraviolet Explorer data revealed a 12 yr activ…
The MUSE Ultra Deep Field (MUDF). VI. The Relationship between Galaxy Properties and Metals in the Circumgalactic Medium
Rafelski, Marc; Beckett, Alexander; Fumagalli, Michele +10 more
We present initial results associating galaxies in the Multi-Unit Spectroscopic Explorer (MUSE) Ultra Deep Field (MUDF) with gas seen in absorption along the line of sight to two bright quasars in this field to explore the dependence of metals in the circumgalactic medium (CGM) on galaxy properties. The MUDF includes ∼140 hr of Very Large Telescop…
Modeling of the Polytropic Index and Temperature Anisotropy in the Solar Wind
Engelbrecht, N. E.; Strauss, R. D.; Desta, Ephrem Tesfaye
The polytropic index is a fundamental physical parameter related to the thermodynamic processes present in space and astrophysical plasmas. This paper investigates the theoretical relationship between the polytropic index and the temperature anisotropy for flow parameters relevant to space plasmas. The derivation is based on the Chew–Goldberger–Lo…
Magnetic Fields in Giant Filaments Probed by the Velocity Gradient Technique: Regular Magnetic Field Interrupted by Magnetization Gaps
Li, Dalei; Tang, Xindi; Zhou, Jianjun +7 more
We study the magnetic field structures in six giant filaments associated with the spiral arms of the Milky Way by applying the velocity gradient technique (VGT) to the 13CO spectroscopic data from the GRS, FUGIN, and SEDIGSM surveys. Unlike dust-polarized emission, the VGT allows us to separate the foreground and background using the ve…
A Possible Correlation between Metallicity and Near-IR Color for Late-M and L Dwarfs
Liu, Michael C.; Zhang, Zhoujian; Zhang, Ruihan
We examine the relationship between metallicity and J - K color for 64 benchmark late-M and L dwarfs, all of which are wide companions to higher-mass stars, and six of which are new discoveries. We assess the correlation between the Δ(J - K) color anomaly (the difference in an object's J - K color from the median color for field objects of the sam…
On the Heating of the Slow Solar Wind by Imbalanced Alfvén-wave Turbulence from 0.06 to 1 au: Parker Solar Probe and Solar Orbiter Observations
Halekas, Jasper S.; Bourouaine, Sofiane; Perez, Jean C. +3 more
In this work we analyze plasma and magnetic field data provided by the Parker Solar Probe and Solar Orbiter missions to investigate the radial evolution of the heating of Alfvénic slow wind by imbalanced Alfvén-wave (AW) turbulent fluctuations from 0.06 to 1 au. in our analysis we focus on slow solar-wind intervals with highly imbalanced and incom…
Probing Disk Ice Content and Polycyclic Aromatic Hydrocarbon Emission through Multiband MagAO+Clio Images of HD 141569
Weinberger, Alycia J.; Close, Laird M.; Males, Jared R. +4 more
We present resolved images of the inner disk component around HD 141569A using the Magellan adaptive optics system with the Clio2 1-5 µm camera, offering a glimpse of a complex system thought to be in a short evolutionary phase between protoplanetary and debris disk stages. We use a reference star along with the Karhunen-Loéve image projecti…
A Catalog of Pulsar X-Ray Filaments
Romani, Roger W.; Dinsmore, Jack T.
We present the first Chandra X-ray Observatory (CXO) catalog of "pulsar X-ray filaments," or "misaligned outflows." These are linear, synchrotron-radiating features powered by ultrarelativistic electrons and positrons that escape from bow shock pulsars. The filaments are misaligned with the (large) pulsar velocity, distinguishing them from the pul…
3He and Fe Spectral Properties in 3He-rich Solar Energetic Particle Events
Rodríguez-Pacheco, J.; Wimmer-Schweingruber, R. F.; Allen, R. C. +4 more
We have surveyed 3He-rich events on the Solar Orbiter mission from 2020 April to 2024 April, selecting isolated injections whose rollover 3He spectral shape is presumed to represent the initial acceleration state, unprocessed by subsequent activity such as coronal mass ejections or jets. A main goal has been to find relations…
ALMA-LEGUS. I. The Influence of Galaxy Morphology on Molecular Cloud Properties
Grebel, Eva K.; Smith, Linda J.; Aloisi, Alessandra +24 more
We present a comparative study of the molecular gas in two galaxies from the Legacy ExtraGalactic UV Survey (LEGUS) sample: barred spiral NGC 1313 and flocculent spiral NGC 7793. These two galaxies have similar masses, metallicities, and star formation rates, but NGC 1313 is forming significantly more massive star clusters than NGC 7793, especiall…