Search Publications
Detection of 2-4 GHz Continuum Emission from ɛ Eridani
Hallinan, G.; Chatterjee, S.; Cordes, J. M. +2 more
The nearby star ɛ Eridani has been a frequent target of radio surveys for stellar emission and extraterrestrial intelligence. Using deep 2-4 GHz observations with the Very Large Array, we have uncovered a 29 µJy compact, steady continuum radio source coincident with ɛ Eridani to within 0"06 (≲2σ; 0.2 au at the distance of the star). Combinin…
Extensive Study of a Coronal Mass Ejection with UV and White-light Coronagraphs: The Need for Multiwavelength Observations
Feng, Li; Lu, Lei; Gan, Weiqun +3 more
Coronal mass ejections (CMEs) often show different features in different bandpasses. By combining data in white-light (WL) and ultraviolet (UV) bands, we have applied different techniques to derive plasma temperatures, electron density, internal radial speed, and so on, within a fast CME. They serve as extensive tests of the diagnostic capabilitie…
Probing the Physical Conditions and Star Formation Processes in the Galactic H II Region S305
Dewangan, L. K.; Ojha, D. K.; Pandey, Rakesh +5 more
We present multiscale and multiwavelength observations of the Galactic H II region S305, which is excited by massive O8.5V and O9.5V stars. Infrared images reveal an extended sphere-like shell (extension ∼7.5 pc; at Td = 17.5-27 K) enclosing the S305 H II region (size ∼5.5 pc; age ∼1.7 Myr). The extended structure observed in the Hersch…
The Velocity Dispersion Function for Quiescent Galaxies in Nine Strong-lensing Clusters
Diaferio, Antonaldo; Hwang, Ho Seong; Geller, Margaret J. +2 more
We measure the central stellar velocity dispersion function for quiescent galaxies in a set of nine northern clusters in the redshift range 0.18 < z < 0.29 and with strong lensing arcs in Hubble Space Telescope images. The velocity dispersion function links galaxies directly to their dark matter halos. From dense SDSS and MMT/Hectospec spect…
Xenon Isotopes Identify Large-scale Nucleosynthetic Heterogeneities across the Solar System
Avice, G.; Moreira, M.; Gilmour, J. D.
Nucleosynthetic isotopic anomalies in meteorites and planetary objects contribute to our understanding of the formation of the solar system. Isotope systematics of chondrites demonstrate the existence of a physical separation between isotopic reservoirs in the solar system. The isotopic composition of atmospheric xenon (Xe) indicates that its prog…
Statistical Properties of Habitable Zones in Stellar Binary Systems
Sozzetti, Alessandro; Vladilo, Giovanni; Silva, Laura +1 more
Observations of exoplanets and protoplanetary disks show that binary stellar systems can host planets in stable orbits. Given the high binary fraction among stars, the contribution of binary systems to Galactic habitability should be quantified. Therefore, we have designed a suite of Monte Carlo experiments aimed at generating large (up to 10…
Simulation of the Interplanetary Bz Using a Data-driven Heliospheric Solar Wind Model
Feng, Xueshang; Zuo, Pingbing; Wei, Fengsi +1 more
Aimed to be ready for the transition from research to operation, we have developed a solar wind model by coupling a data-driven empirical coronal model with a magnetohydrodynamics heliospheric model. We performed a data-driven simulation of the solar wind for a two-year period during the declining and minimum phases of solar cycle 23. Comparisons …
X-Ray Emission and Disk Irradiation of HL Tau and HD 100546
Skinner, Stephen L.; Güdel, Manuel
We present new X-ray observations of the optically obscured protostar HL Tau and the intermediate-mass Herbig Be star HD 100546. Both objects are surrounded by spectacular disks showing complex morphology, including rings and gaps that may have been sculpted by protoplanets. HL Tau was detected as a variable hard X-ray source by Chandra, typical o…
The Solar Origin of Particle Events Measured by Parker Solar Probe
Vourlidas, Angelos; Poirier, Nicolas; Kouloumvakos, Athanasios +4 more
During the second solar encounter phase of Parker Solar Probe (PSP), two small solar energetic particle (SEP) events were observed by the Integrated Science Investigation of the Sun, on 2019 April 2 and 4. At the time, PSP was approaching its second perihelion at a distance of ∼24.8 million kilometers from the solar center, it was in near-radial a…
CS Depletion in Prestellar Cores
Soam, Archana; Kim, Shinyoung; Kim, Gwanjeong +6 more
The CS molecule is known to be adsorbed onto dust in cold and dense conditions, causing it to be significantly depleted in the central region of cores. This study is aimed to investigate the depletion of the CS molecule using the optically thin {C}34{S} molecular line observations. We mapped five prestellar cores, L1544, L1552, L1689B, …