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The Lyα Emission in a C1.4 Solar Flare Observed by the Extreme Ultraviolet Imager aboard Solar Orbiter
Krucker, Säm; Gan, Weiqun; Ding, M. D. +7 more
The hydrogen Lyα (H I Lyα) emission during solar flares has rarely been studied in spatially resolved images, and its physical origin has not been fully understood. In this paper, we present novel Lyα images for a C1.4 solar flare (SOL2021-08-20T22:00) from the Extreme Ultraviolet Imager aboard Solar Orbiter, together with multi-wave-band and mult…
Informed Systematic Method to Identify Variable Mid- and Late-T Dwarfs
Karalidi, Theodora; Manjavacas, Elena; Faherty, Jacqueline K. +5 more
The majority of brown dwarfs show some level of photometric or spectrophotometric variability in different wavelength ranges. This variability allow us to trace the 3D atmospheric structures of variable brown dwarfs and directly-imaged exoplanets with radiative-transfer models and mapping codes. Nevertheless, to date, we do not have an informed me…
Detection of Gravitational Redshift in Open Cluster Nondegenerate Stars
Gutiérrez, Carlos M.; Ramos-Chernenko, Nataliya
A key observational prediction of Einstein's Equivalence Principle is that light undergoes redshift when it escapes from a gravitational field. Although astrophysics provides a wide variety of physical conditions in which this redshift should be significant, until very recently the observational evidence for this gravitational effect was limited t…
The Temporal and Spatial Behaviors of CME Occurrence Rate at Different Latitudes
Mei, Ying; Wang, Feng; Deng, Hui +3 more
The statistical study of the coronal mass ejections (CMEs) is a hot topic in solar physics. To further reveal the temporal and spatial behaviors of the CMEs at different latitudes and heights, we analyzed the correlation and phase relationships between the occurrence rate of CMEs, the coronal brightness index (CBI), and the 10.7 cm solar radio flu…
A Statistical Detection of Wide Binary Systems in the Ultrafaint Dwarf Galaxy Reticulum II
Loeb, Abraham; Simon, Joshua D.; Safarzadeh, Mohammadtaher
Binary stars can inflate the observed velocity dispersion of stars in dark matter-dominated systems such as ultrafaint dwarf galaxies (UFDs). However, the population of binaries in UFDs is poorly constrained by observations, with preferred binary fractions for individual galaxies ranging from a few percent to near unity. Searching for wide binarie…
The Massive and Distant Clusters of WISE Survey. XI. Stellar Mass Fractions and Luminosity Functions of MaDCoWS Clusters at z 1
Mroczkowski, Tony; Connor, Thomas; Eisenhardt, Peter R. M. +14 more
We present stellar mass fractions and composite luminosity functions (LFs) for a sample of 12 clusters from the Massive and Distant Clusters of WISE Survey (MaDCoWS) in the redshift range 0.951 ≤ z ≤ 1.43. Using spectral energy distribution fitting of optical and deep mid-infrared photometry, we establish the membership of objects along the lines …
A Study of Dimmings, CMEs, and Flares during the STEREO-SOHO Quadrature
Krista, Larisza D.; Manning, Drew; West, Matthew J.
During the quadrature period (2010 December-2011 August) the STEREO-A and B satellites were approximately at right angles to the SOHO satellite. This alignment was particularly advantageous for determining the coronal mass ejection (CME) properties, since the closer a CME propagates to the plane of sky, the smaller the measurement inaccuracies are…
Bulk Properties of Pickup Ions Derived from the Ulysses Solar Wind Ion Composition Spectrometer Data
Zhang, Ming; Gedalin, Michael; Pogorelov, Nikolai V. +3 more
Nonthermal, pickup ions (PUIs) represent an energetic component of the solar wind (SW). While a number of theoretical models have been proposed to describe the PUI flow, of major importance are in situ measurements providing us with the vital source of model validation. The Solar Wind Ion Composition Spectrometer (SWICS) instrument on board the Ul…
Carbon Abundances in Compact Galactic Planetary Nebulae: An Ultraviolet Spectroscopic Study with the Space Telescope Imaging Spectrograph (STIS)
Ventura, Paolo; Shaw, Richard A.; García-Hernández, D. A. +3 more
We surveyed a sample of compact Galactic planetary nebulae (PNe) with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope (HST) to determine their gas-phase carbon abundances. Carbon abundances in PNe constrain the nature of their asymptotic giant branch (AGB) progenitors, as well as cosmic recycling. We measured the carbon abun…
Standing Solitary Waves as Transitions to Spiral Structures in Gravitationally Unstable Accretion Disks
Deng, Hongping; Ogilvie, Gordon I.
Astrophysical disks that are sufficiently cold and dense are linearly unstable to the formation of axisymmetric rings as a result of the disk's gravity. In practice, spiral structures are formed, which may in turn produce bound fragments. We study a nonlinear dynamical path that can explain the development of spirals in a local model of a gaseous …