Search Publications
Molecular gas along the old radio jets of the cluster-central type 2 quasar IRAS 09104+4109
Babul, Arif; Phadke, Kedar A.; Chapman, Scott +4 more
We present Northern Extended Millimeter Array (NOEMA) CO(2-1) maps of the z = 0.4418 cluster-central quasi-stellar object (QSO) IRAS 09104+4109, which trace ~4.5 × 1010 M⊙ of molecular gas in and around the galaxy. As in many low-redshift cool-core clusters, the molecular gas is located in a series of clumps extending along t…
Ultra-High-Resolution 1 m/pixel CaSSIS DTM Using Super-Resolution Restoration and Shape-from-Shading: Demonstration over Oxia Planum on Mars
Tao, Yu; Muller, Jan-Peter; Conway, Susan J. +3 more
EvryFlare. IV. Detection of Periodicity in Flare Occurrence from Cool Stars with TESS
Law, Nicholas M.; Howard, Ward S.
Phased flaring, or the periodic occurrence of stellar flares, may probe electromagnetic star-planet interaction (SPI), binary interaction, or magnetic conditions in spots. For the first time, we explore flare periodograms for a large sample of flare stars to identify periodicity due to magnetic interactions with orbiting companions, magnetic reser…
Binary-driven stellar rotation evolution at the main-sequence turn-off in star clusters
Albrow, Michael D.; Deng, Licai; de Grijs, Richard +1 more
The impact of stellar rotation on the morphology of star cluster colour-magnitude diagrams is widely acknowledged. However, the physics driving the distribution of the equatorial rotation velocities of main-sequence turn-off stars is as yet poorly understood. Using Gaia Data Release 2 photometry and new Southern African Large Telescope medium-reso…
White Dwarf Photospheric Abundances in Cataclysmic Variables. I. SS Aurigae and TU Mensae
Sion, Edward M.; Godon, Patrick
Chemical abundance studies of cataclysmic variables have revealed high nitrogen to carbon ratios in a number of cataclysmic variable white dwarfs (based on ultraviolet emission and absorption lines), as well as possible carbon deficiency in many secondaries (based on the absence of infrared CO absorption lines). These indicate that the accreted ma…
Reconstructing three-dimensional densities from two-dimensional observations of molecular gas
Gutermuth, Robert A.; Pokhrel, Riwaj; Federrath, Christoph +2 more
Star formation has long been known to be an inefficient process, in the sense that only a small fraction ϵff of the mass of any given gas cloud is converted to stars per cloud free-fall time. However, developing a successful theory of star formation will require measurements of both the mean value of ϵff and its scatter from …
12C/13C ratio and CNO abundances in the classical very old metal-poor dwarf HD 140283
Spite, M.; Barbuy, B.; Spite, F.
Context. The isotope abundances provide powerful diagnostics of the chemical enrichment in our Galaxy. The star HD 140283 is one of the best-studied very metal-poor dwarf stars. It is very old, and the chemical abundance in this star is a good witness of the chemical composition of the matter in the early Galaxy.
Aims: The aim of this work is…
Multifrequency high spectral resolution observations of HCN toward the circumstellar envelope of Y Canum Venaticorum
Santander-García, M.; Cernicharo, J.; Greathouse, T. K. +7 more
High spectral resolution observations toward the low mass-loss rate C-rich, J-type asymptotic giant branch (AGB) star Y CVn were carried out at 7.5, 13.1, and 14.0 µm with the Echelon-cross-echelle Spectrograph mounted on the Stratospheric Observatory for Infrared Astronomy and the Texas Echelon-cross-echelle Spectrograph on the Infrared Tel…
ALMA observations of the early stages of substellar formation in the Lupus 1 and 3 molecular clouds
Hales, A.; de Gregorio-Monsalvo, I.; Bayo, A. +10 more
Context. The dominant mechanism leading to the formation of brown dwarfs (BDs) remains uncertain. While the census of Class II analogs in the substellar domain continues to grow, the most direct keys to formation, which are obtained from younger objects (pre-BD cores and proto-BDs), are limited by the very low number statistics available.
Aim…
Multi-wavelength VLTI study of the puffed-up inner rim of a circumbinary disc
Min, M.; Van Winckel, H.; Kamath, D. +3 more
Context. The presence of stable, compact circumbinary discs of gas and dust around post-asymptotic giant branch (post-AGB) binary systems has been well established. We focus on one such system, IRAS 08544−4431.
Aims: We present an interferometric multi-wavelength analysis of the circumstellar environment of IRAS 08544−4431. The aim is to cons…