Search Publications
Missions
Journals
Publication Years
Asteroseismology of the DAV Star L19-2
Chen, Yanhui
L19-2 is a DAV star, which was intermittently observed from 1976 to 2013. Five independent pulsation modes of 350, 192, 143, 118, and 113 s are identified. The five modes can be used to constrain the fitting models. The rates of period change can be obtained through the O-C method for the modes of 192 and 113 s, which can be used to study the evol…
Ephemerides of the Irregular Saturnian Satellites from Earth-based Astrometry and Cassini Imaging
Jacobson, Robert A.; Sheppard, Scott S.; Brozović, Marina +2 more
We report a new determination of the orbits of the irregular Saturnian satellites. We fit their numerically integrated orbits to a data set containing Earth-based observations and imaging data from the Cassini spacecraft. We include the statistics of the observation residuals, the satellites' orbital elements, and projected accuracies of the satel…
The η Aquilae System: Radial Velocities and Astrometry in Search of η Aql B
Cochran, William D.; Harrison, Thomas E.; Anderson, Richard I. +4 more
The classical Cepheid η Aql was not included in past Leavitt Law work because of a presumed complicating orbit due to a known B9.8V companion. To determine the orbit of η Aql B, we analyze a significant number of radial velocity (RV) measurements from eight sources. With these we establish the RV variation due to Cepheid pulsation, using a model w…
A Very Metal-poor RR Lyrae Star with a Disk Orbit Found in the Solar Neighborhood
Kobayashi, Naoto; Maehara, Hiroyuki; Hattori, Kohei +28 more
Metal-deficient stars are important tracers for understanding the early formation of the Galaxy. Recent large-scale surveys with both photometric and spectroscopic data have reported an increasing number of metal-deficient stars whose kinematic features are consistent with those of the disk stellar populations. We report the discovery of an RR Lyr…
Probabilistic orbits and dynamical masses of emission-line binaries
Grant, David; Blundell, Katherine
The observed orbits of emission-line stars may be affected by systematics owing to their broad emission lines being formed in complex and extended environments. This is problematic when orbital parameter probability distributions are estimated assuming radial-velocity data are solely comprised of Keplerian motion plus Gaussian white noise, leading…
Existence of tidal tails for the globular cluster NGC 5824
Zhao, Gang; Zhao, Jing-Kun; Ishigaki, Miho N. +5 more
Context. Several dynamically cold streams have been associated with certain globular clusters (GCs) based on orbital energies and angular momenta. Some of these streams are surprisingly far apart from their progenitors and one such pair is Triangulum and NGC 5824. Triangulum can be considered as a piece of the leading tail of NGC 5824 since the cl…
White Dwarf Photospheric Abundances in Cataclysmic Variables-II. White Dwarfs with and without a Mask
Sion, Edward M.; Godon, Patrick
Taking advantage of the now-available Gaia EDR3 parallaxes, we carry out an archival Hubble Space Telescope (HST) far-ultraviolet spectroscopic analysis of 10 cataclysmic variable systems, including five carefully selected eclipsing systems. We obtain accurate white dwarf (WD) masses and temperatures, in excellent agreement with the masses for fou…
Tracing a decade of activity towards a yellow hypergiant. The spectral and spatial morphology of IRC+10420 at au scales
de Wit, W. -J.; Black, J. H.; Mérand, A. +3 more
The fate of a massive star during the latest stages of its evolution is highly dependent on its mass-loss history and geometry, with the yellow hypergiants (YHGs) being key objects. We present near-IR interferometric observations of the famous YHG IRC+10420 and blue spectra taken between 1994 and 2019. Our 2.2-µm GRAVITY/VLTI observations at…
The probabilistic random forest applied to the QUBRICS survey: improving the selection of high-redshift quasars with synthetic data
Grazian, Andrea; Murphy, Michael T.; Boutsia, Konstantina +10 more
Several recent works have focused on the search for bright, high-z quasars (QSOs) in the South. Among them, the QUasars as BRIght beacons for Cosmology in the Southern hemisphere (QUBRICS) survey has now delivered hundreds of new spectroscopically confirmed QSOs selected by means of machine learning algorithms. Building upon the results obtained b…
The uncertain interstellar medium of high-redshift quiescent galaxies: Impact of methodology
Daddi, E.; Gobat, R.; Caminha, G. B. +3 more
How much gas and dust is contained in high-redshift quiescent galaxies (QGs) is currently an open question with relatively few and contradictory answers, as well as important implications for our understanding of the nature of star formation quenching processes at cosmic noon. Here we revisit far-infrared (FIR) observations of the REQUIEM-ALMA sam…