Search Publications
Probing the initial conditions of high-mass star formation. III. Fragmentation and triggered star formation
Zhang, Chuan-Peng; Li, Guang-Xing; Wyrowski, Friedrich +6 more
Context. Fragmentation and feedback are two important processes during the early phases of star formation.
Aims: Massive clumps tend to fragment into clusters of cores and condensations, some of which form high-mass stars. In this work, we study the structure of massive clumps at different scales, analyze the fragmentation process, and invest…
The Convective Electric Field Influence on the Cold Plasma and Diamagnetic Cavity of Comet 67P
Henri, Pierre; Nilsson, Hans; Edberg, Niklas J. T. +5 more
We studied the distribution of cold electrons (<1 eV) around comet 67P/Churyumov-Gerasimenko with respect to the solar wind convective electric field direction. The cold plasma was measured by the Langmuir Probe instrument and the direction of the convective electric field {\boldsymbol{E}} conv = -{\boldsymbol{v}} × {\boldsymbol{B}} …
The Pivot Energy of Solar Energetic Particles Affecting the Martian Surface Radiation Environment
Wang, Yuming; Guo, Jingnan; Wimmer-Schweingruber, Robert F. +5 more
Space radiation is a major risk for humans, especially on long-duration missions to outer space, e.g., a manned mission to Mars. Galactic cosmic rays contribute a predictable radiation background; the main risk is due to the highly variable and currently unpredictable flux of solar energetic particles (SEPs). Such sporadic SEP events may induce ac…
Surface Temperatures and Water Ice Sublimation Rate of Oxo Crater: A Comparison With Juling Crater
Raponi, A.; De Sanctis, M. C.; Formisano, M. +3 more
Dwarf planet Ceres is characterized by several sites hosting (or have hosted) ice-rich patches as revealed by the Dawn's Visible and InfraRed spectrometer. The study of the illumination conditions including the effects of the local topography become critical in the estimation of the ice lifetime as well as the water vapor production rate. In this …
Herschel-HOBYS study of the earliest phases of high-mass star formation in NGC 6357
White, G. J.; Könyves, V.; Rygl, K. L. J. +19 more
Aims: To constrain models of high-mass star formation it is important to identify the massive dense cores (MDCs) that are able to form high-mass star(s). This is one of the purposes of the Herschel/HOBYS key programme. Here, we carry out the census and characterise of the properties of the MDCs population of the NGC 6357 H II region.
Met…
Even Simpler Modeling of Quadruply Lensed Quasars (and Random Quartets) Using Witt's Hyperbola
Schechter, Paul L.; Wynne, Raymond A.
Witt (1996) has shown that, for an elliptical potential, the four images of a quadruply lensed quasar lie on a rectangular hyperbola that passes through the unlensed quasar position and the center of the potential as well. Wynne & Schechter (2018) have shown that, for the singular isothermal elliptical potential (SIEP), the four images also li…
Observations of the Ultraviolet-bright Star Barnard 29 in the Globular Cluster M13 (NGC 6205)
Chayer, Pierre; Reid, I. N.; Dixon, William V. +1 more
We have analyzed spectra from FUSE, COS, GHRS, and Keck HIRES of the UV-bright star Barnard 29 in M13 (NGC 6205). By comparing the photospheric abundances derived from multiple ionization states of C, N, O, Si, and S, we infer an effective temperature {T}eff} = 21,400 ± 400 K. Balmer-line fits yield a surface gravity {log}g = 3.10 ± 0.0…
FIFI-LS Observations of the Circumnuclear Ring— Probing the High-density Phase of the PDR
Poglitsch, A.; Looney, L. W.; Krabbe, A. +13 more
We investigate the nature of dense gas in the 3-10 pc circumnuclear ring (CNR) in the galactic center of the Milky Way, which is a structure that may be dynamically connecting the supermassive black hole Sgr A* with the central molecular zone at the 100 pc scale, and is the closest reservoir of molecular gas to the massive stars located within the…
Measuring the Absolute Total Intrinsic Redshifts (Surface Gravity Plus the Convective Blueshift) of the Main-sequence Stars and Red Giants using Gaia Data
Dai, De-Chang; Stojkovic, Dejan; Li, ZhiGang
We analyze the GAIA release II data to demonstrate how one can measure the absolute total intrinsic redshifts of the main-sequence stars and red giants. We remove the relative velocity components of the stars’ motion with respect to the Sun by doing the analysis in the local standard of the rest frame defined by the average stars’ motion. We provi…
High Confidence Optical Confirmations among the High Signal-to-noise Planck Cluster Candidates
Infante, L.; Hughes, John P.; Doze, Peter +3 more
We report on newly identified galaxy clusters from the high signal-to-noise (>5σ) end of the second all-sky Planck Sunyaev-Zel’dovich (SZ) catalog (PSZ2). The clusters are identified in deep, optical imaging from the Kitt Peak National Observatory 4 m Mayall telescope taken between 2014 and 2017. Here we focus on the highest richness systems, a…