Search Publications
Intensity Enhancement of O VI Ultraviolet Emission Lines in Solar Spectra due to Opacity
Doyle, J. G.; Madjarska, M. S.; Mathioudakis, M. +5 more
Opacity is a property of many plasmas. It is normally expected that if an emission line in a plasma becomes optically thick, then its intensity ratio to that of another transition that remains optically thin should decrease. However, radiative transfer calculations undertaken both by ourselves and others predict that under certain conditions the i…
Spatial Nonlocality of the Small-scale Solar Dynamo
Lamb, D. A.; DeForest, C. E.; Howard, T. A.
We explore the nature of the small-scale solar dynamo by tracking magnetic features. We investigate two previously explored categories of the small-scale solar dynamo: shallow and deep. Recent modeling work on the shallow dynamo has produced a number of scenarios for how a strong network concentration can influence the formation and polarity of ne…
Orbits for Eight Hipparcos Double Stars
Cvetković, Z.; Pavlović, R.; Ninković, S.
In this paper, we analyze new orbital elements and the quantities that follow from them for eight binaries: WDS 00101+3825 = HDS 23Da,Db, WDS 00321-1218 = HDS 71, WDS 04287+2613 = HDS 576, WDS 04389-1207 = HDS 599, WDS 16206+4535 = HDS 2309, WDS 17155+1052 = HDS 2440, WDS 22161-0705 = HDS 3158, and WDS 23167+3441 = HDS 3315. For seven of them, the…
Radiation in the neighbourhood of a double layer
Berthomier, M.; Pickett, J.; Pottelette, R.
In the auroral kilometric radiation (AKR) source region, acceleration layers narrow in altitude and associated with parallel field-aligned potential drops of several kV can be identified by using both particles and wave-field high time-resolution measurements from the Fast Auroral SnapshoT explorer spacecraft (FAST). These so-called double layers …
Quantitative analysis of the morphology of martian gullies and insights into their formation
Yue, Z.; Hu, W.; Liu, B. +4 more
The process of formation of observed geologically recent gully features on Mars has remained a topic of intense debate since their discovery. In this study, we performed quantitative morphological analysis on certain parameters of gullies from different settings, such as crater walls, terraces, and sand dunes, on the martian surface in addition to…
Mid-infrared Imaging of the Bipolar Planetary Nebula M2-9 from SOFIA
Sahai, R.; Schoenwald, J.; Lykou, F. +10 more
We have imaged the bipolar planetary nebula M2-9 using SOFIA's FORCAST instrument in six wavelength bands between 6.6 and 37.1 µm. A bright central point source, unresolved with SOFIA's ~4''-5'' beam, is seen at each wavelength, and the extended bipolar lobes are clearly seen at 19.7 µm and beyond. The photometry between 10 and 25 &mic…
The 2-24 µm source counts from the AKARI North Ecliptic Pole survey
Pearson, C. P.; Goto, T.; Matsuhara, H. +3 more
We present herein galaxy number counts of the nine bands in the 2-24 µm range on the basis of the AKARI North Ecliptic Pole (NEP) surveys. The number counts are derived from NEP-deep and NEP-wide surveys, which cover areas of 0.5 and 5.8 deg2, respectively. To produce reliable number counts, the sources were extracted from recentl…
Plasma Heating in Solar Flares and their Soft and Hard X-Ray Emissions
Falewicz, R.
In this paper, the energy budgets of two single-loop-like flares observed in X-ray are analyzed under the assumption that nonthermal electrons (NTEs) are the only source of plasma heating during all phases of both events. The flares were observed by RHESSI and GOES on 2002 February 20 and June 2, respectively. Using a one-dimensional (1D) hydrodyn…
Suprathermal magnetospheric minor ions heavier than water at Saturn: Discovery of 28M+ seasonal variations
Krimigis, S. M.; Mitchell, D. G.; Hamilton, D. C. +2 more
Water group ions W+ (O+, OH+, H2O+, and H3O+), along with H+ and H2+, dominate Saturn's near-equatorial magnetospheric suprathermal ion populations. The singly charged, minor heavy ions O2+ and 28M+
An HST COS "SNAPshot" Spectrum of the K Supergiant λ Vel (K4Ib-II)
Ayres, Thomas R.; Harper, Graham M.; Carpenter, Kenneth G. +3 more
We present a far-ultraviolet spectrum of the K4 Ib-II supergiant λ Vel obtained with the Hubble Space Telescope's Cosmic Origins Spectrograph (COS) as a part of the SNAPshot program "SNAPing coronal iron" (GO 11687). The observation covers a wavelength region (1326-1467 Å) not previously recorded for λ Vel at a spectral resolving power of R ~ 20,0…