Search Publications
Interplay between pulsation, mass loss, and third dredge-up: More about Miras with and without technetium
Bernhard, K.; Cristallo, S.; McDonald, I. +2 more
Context. We follow-up on a previous finding that AGB Mira variables containing the third dredge-up indicator technetium (Tc) in their atmosphere form a different sequence of K - [22] colour as a function of pulsation period than Miras without Tc. A near- to mid-infrared colour such as K - [22] is a good probe for the dust mass-loss rate of the sta…
Discovery of the first resolved triple white dwarf
Hermes, J. J.; Gänsicke, B. T.; Tremblay, P. -E. +4 more
We report the discovery of J1953-1019, the first resolved triple white dwarf system. The triplet consists of an inner white dwarf binary and a wider companion. Using Gaia DR2 photometry and astrometry combined with our follow-up spectroscopy, we derive effective temperatures, surface gravities, masses, and cooling ages of the three components. All…
A new line on the wide binary test of gravity
Banik, Indranil
The relative velocity distribution of wide binary (WB) stars is sensitive to the law of gravity at the low accelerations typical of galactic outskirts. I consider the feasibility of this wide binary test using the `line velocity' method. This involves considering only the velocity components along the direction within the sky plane orthogonal to t…
2D Isotropic Feature of Solar Wind Turbulence as Shown by Self-correlation Level Contours at Hour Timescales
He, Jiansen; Wang, Xin; Tu, Chuanyi
The slow wind anisotropy is observed by Dasso et al. as elongation along the magnetic field direction in the magnetic self-correlation contours calculated from data sets of two-day-long data and averaged for five years in 1998-2002, which is consistent with prediction by the “critical balance cascade theory.” More pronounced elongation at smaller …
Phase Curves from the Kuiper Belt: Photometric Properties of Distant Kuiper Belt Objects Observed by New Horizons
Buratti, Bonnie J.; Singer, Kelsi N.; Stern, S. Alan +17 more
Prior to its close encounter with the Kuiper Belt object (KBO) (486958) 2014 MU69 on 2019 January 1, NASA’s New Horizons spacecraft observed other KBOs from distances greater than 0.1 au at solar phase angles far larger than those attainable from Earth. The expanded range in phase angle afforded by these distant KBO (DKBO) observations …
Ultraluminous X-ray sources with flat-topped noise and QPO
Fabrika, Sergei; Atapin, Kirill; Caballero-García, Maria D.
We analysed the X-ray power density spectra of five ultraluminous X-ray sources (ULXs) NGC 5408 X-1, NGC 6946 X-1, M 82 X-1, NGC 1313 X-1, and IC 342 X-1 that are the only ULXs that display both flat-topped noise (FTN) and quasi-periodic oscillations (QPOs). We studied the QPO frequencies, fractional root-mean-square (rms) variability, X-ray lumin…
Particle acceleration in the Herbig-Haro objects HH 80 and HH 81
Carrasco-González, Carlos; Vig, Sarita; González-Martín, Omaira +4 more
We present an analysis of radio (Karl G. Jansky Very Large Array (VLA)), optical (Hubble Space Telescope (HST)), and X-ray (Chandra and XMM-Newton) observations and archival data of the Herbig-Haro objects HH 80 and HH 81 in the context of jet-cloud interactions. Our radio images are the highest angular resolution to date of these objects, allowin…
Three-dimensional Density Structure of a Solar Coronal Streamer Observed by SOHO/LASCO and STEREO/COR2 in Quadrature
Van Doorsselaere, Tom; Zhukov, Andrei N.; Decraemer, Bieke
Helmet streamers are a prominent manifestation of magnetic structures with current sheets in the solar corona. These large-scale structures are regions with high plasma density, overlying active regions and filament channels. We investigate the three-dimensional (3D) structure of a coronal streamer, observed simultaneously by white-light coronagra…
High-Frequency Wave Generation in Magnetotail Reconnection: Nonlinear Harmonics of Upper Hybrid Waves
Graham, Daniel B.; Yoon, Peter H.; Sibeck, David G. +4 more
MMS3 spacecraft passed the vicinity of the electron diffusion region of magnetotail reconnection on 3 July 2017, observing discrepancies between perpendicular electron bulk velocities and E>→×B>→ drift, and agyrotropic electron crescent distributions. Analyzing linear wave dispersions, Burch et al. (2019,
{k}_{\perp }^{-8/3} Spectrum in Kinetic Alfvén Wave Turbulence: Implications for the Solar Wind
David, Vincent; Galtier, Sébastien
The nature of solar wind turbulence at large scale is rather well understood in the theoretical framework of magnetohydrodynamics. The situation is quite different at subproton scales where the magnetic energy spectrum measured by different spacecraft does not fit with the classical turbulence predictions: a power-law index close to -8/3 is genera…