Search Publications
The shortest-period Wolf-Rayet binary in the Small Magellanic Cloud: Part of a high-order multiple system. Spectral and orbital analysis of SMC AB 6
Sander, A.; Hamann, W. -R.; Oskinova, L. M. +8 more
Context. SMC AB 6 is the shortest-period (P = 6.5 d) Wolf-Rayet (WR) binary in the Small Magellanic Cloud. This binary is therefore a key system in the study of binary interaction and formation of WR stars at low metallicity. The WR component in AB 6 was previously found to be very luminous (log L = 6.3 [L⊙]) compared to its reported or…
Evidence for Auroral Emissions From Callisto's Footprint in HST UV Images
Gérard, Jean-Claude; Clarke, John T.; Grodent, Denis +3 more
Auroral emissions are expected from the footprint of Callisto in Jupiter's upper atmosphere owing to the known interaction of its atmosphere with Jupiter's magnetosphere, and from the observed auroral emissions from the footprints of the other three Galilean satellites. The mapping of Callisto along modeled magnetic field lines at Jupiter, however…
Massive stereo-based DTM production for Mars on cloud computers
Tao, Y.; Muller, J. -P.; Sidiropoulos, P. +5 more
Digital Terrain Model (DTM) creation is essential to improving our understanding of the formation processes of the Martian surface. Although there have been previous demonstrations of open-source or commercial planetary 3D reconstruction software, planetary scientists are still struggling with creating good quality DTMs that meet their science nee…
Chemical Compositions of Evolved Stars from Near-infrared IGRINS High-resolution Spectra. I. Abundances in Three Red Horizontal Branch Stars
Kim, Hwihyun; Jaffe, Daniel T.; Mace, Gregory N. +6 more
We have derived elemental abundances of three field red horizontal branch stars using high-resolution (R ≃ 45,000), high signal-to-noise ratio (S/N ≳ 200) H- and K-band spectra obtained with the Immersion Grating Infrared Spectrograph (IGRINS). We have determined the abundances of 21 elements, including α (Mg, Si, Ca, S), odd-Z (Na, Al, P, K), Fe-…
The Properties of Planck Galactic Cold Clumps in the L1495 Dark Cloud
Sanhueza, Patricio; Soam, Archana; Di Francesco, James +19 more
Planck Galactic Cold Clumps (PGCCs) possibly represent the early stages of star formation. To understand better the properties of PGCCs, we studied 16 PGCCs in the L1495 cloud with molecular lines and continuum data from Herschel, JCMT/SCUBA-2, and the PMO 13.7 m telescope. Thirty dense cores were identified in 16 PGCCs from 2D Gaussian fitting. T…
Using the CIFIST grid of CO5BOLD 3D model atmospheres to study the effects of stellar granulation on photometric colours. I. Grids of 3D corrections in the UBVRI, 2MASS, HIPPARCOS, Gaia, and SDSS systems
Steffen, M.; Ludwig, H. -G.; Bonifacio, P. +9 more
Context. The atmospheres of cool stars are temporally and spatially inhomogeneous due to the effects of convection. The influence of this inhomogeneity, referred to as granulation, on colours has never been investigated over a large range of effective temperatures and gravities. Aim. We aim to study, in a quantitative way, the impact of granulatio…
A Multi-instrument and Multi-wavelength High Angular Resolution Study of MWC 614: Quantum Heated Particles Inside the Disk Cavity
Monnier, John D.; Kraus, Stefan; Hinkley, Sasha +13 more
High angular resolution observations of young stellar objects are required to study the inner astronomical units of protoplanetary disks in which the majority of planets form. As they evolve, gaps open up in the inner disk regions and the disks are fully dispersed within ∼10 Myr. MWC 614 is a pretransitional object with a ∼10 au radius gap. We pre…
Incorporating Uncertainties in Atomic Data into the Analysis of Solar and Stellar Observations: A Case Study in Fe XIII
Del Zanna, Giulio; Warren, Harry P.; van Dyk, David A. +6 more
Information about the physical properties of astrophysical objects cannot be measured directly but is inferred by interpreting spectroscopic observations in the context of atomic physics calculations. Ratios of emission lines, for example, can be used to infer the electron density of the emitting plasma. Similarly, the relative intensities of emis…
Distant White Dwarfs in the US Naval Observatory Flagstaff Station Parallax Sample
Bergeron, P.; Xu, Siyi; Dufour, P. +18 more
This paper presents new trigonometric parallaxes and proper motions for 214 stars. The measurements were made at the US Naval Observatory Flagstaff Station between 1989 and 2017, and the average uncertainty in the parallax values is 0.6 mas. We find good agreement with Gaia Data Release 2 measurements for the stars in common, although there may be…
Discovery of a New Fundamental Plane Dictating Galaxy Cluster Evolution from Gravitational Lensing
Donahue, Megan; Umetsu, Keiichi; Medezinski, Elinor +5 more
In cold dark-matter (CDM) cosmology, objects in the universe have grown under the effect of gravity of dark matter. The intracluster gas in a galaxy cluster was heated when the dark-matter halo formed through gravitational collapse. The potential energy of the gas was converted to thermal energy through this process. However, this process and the …