Search Publications
Turbulent Heating in Solar Wind Thermodynamics
Livadiotis, G.
This paper considers the concept of wave-particle thermodynamic equilibrium in order to improve our understanding of the role of turbulent heating in the solar wind proton plasma. The thermodynamic equilibrium in plasmas requires the energy of a plasmon—the quantum of plasma fundamental oscillation—to be balanced by the proton-magnetized plasma en…
Low-frequency GMRT observations of ultra-cool dwarfs
Chandra, Poonam; Kaplan, David L.; Murphy, Tara +2 more
Observations of radio emission in about 10 per cent of ultra-cool dwarfs (UCDs) indicate the presence of strong, persistent magnetic fields in these stars. These results are in contrast to early theoretical expectations on fully convective dynamos, and to other tracers of magnetic activity, such as H α and X-ray luminosity. Radio-frequency observa…
Cosmology with extragalactic proper motions: harmonic formalism, estimators, and forecasts
Hall, Alex
We conduct a thorough study into the feasibility of measuring large-scale correlated proper motions of galaxies with astrometric surveys. We introduce a harmonic formalism for analysing proper motions and their correlation functions on the sphere based on spin-weighted spherical harmonics, and study the statistics of the transverse velocity field …
Tracking the Footprints of the Radio Pulsar B1727-47: Proper Motion, Host Supernova Remnant, and the Glitches
Shternin, P.; Kirichenko, A.; Zyuzin, D. +4 more
The bright radio pulsar B1727-47, with a characteristic age of 80 kyr, was among the first pulsars discovered 50 yr ago. Using regular timing observations and its interferometric positions at three epochs, we measured, for the first time, the pulsar proper motion of 151 ± 19 mas yr-1. At the dispersion measure distance of ≳2.7 kpc, this…
First Detection of Submillimeter-wave [13C I] 3 P 1-3 P 0 Emission in a Gaseous Debris Disk of 49 Ceti with ALMA
Yamamoto, Satoshi; Higuchi, Aya E.; Oya, Yoko
We have detected the submillimeter-wave fine-structure transition (3 P 1-3 P 0) of 13C, [13C I], in the gaseous debris disk of 49 Ceti with the Atacama Large Millimeter/submillimeter Array (ALMA). Recently, the [C I] 3 P 1-3 P 0 emission h…
Praesepe white dwarfs in Gaia DR2
Salaris, M.; Bedin, L. R.
We have exploited Gaia Data Release 2 to study white dwarf members of the Praesepe star cluster. We recovered 11 known white dwarf members (all DA spectral type) plus a new cluster WD never identified before. 2 of the 11 known DA objects did not satisfy all quality indicators available in the data release. The remaining nine objects of known spect…
Dynamical Masses for the Triple System HD 28363 in the Hyades Cluster
Torres, Guillermo; Latham, David W.; Stefanik, Robert P.
The star HD 28363 in the Hyades cluster has been known for over a century as a visual binary with a period of 40 yr. The secondary is, in turn, a single-lined spectroscopic binary with a 21 day period. Here we report extensive spectroscopic monitoring of this hierarchical triple system that reveals the spectral lines of the third star for the firs…
The discovery of a Li/Na-rich giant star in Omega Centauri: formed from the pure ejecta of super-AGB stars?
Salaris, M.; Bonifacio, P.; Monaco, L. +3 more
We report the discovery of two Li-rich giant stars (fainter than the red giant branch (RGB) bump) in the stellar system Omega Centauri using GIRAFFE-FLAMES spectra. These two stars have A(Li) = 1.65 and 2.40 dex and they belong to the main population of the system ([Fe/H] = -1.70 and -1.82, respectively). The most Li-rich of them (#25664) has [Na/…
Position-dependent microchannel plate gain correction in Rosetta's ROSINA/DFMS mass spectrometer
Altwegg, K.; Balsiger, H.; Fuselier, S. A. +7 more
Dissecting a Disk-instability Outburst in a Symbiotic Star: NuSTAR and Swift Observations of T Coronae Borealis during the Rise to the “Superactive” State
Nelson, T.; Mukai, K.; Sokoloski, J. L. +1 more
The current superactive state of the recurrent nova T Coronae Borealis (T CrB) has been observed with unprecedented detail. Previously published observations provide strong evidence that this state is due to an enhancement of the flow of material through the accretion disk, which increased the optical depth of its most internal region, the boundar…