Search Publications
Chemically peculiar stars as members of open clusters
Paunzen, E.; Prišegen, M.; Faltová, N. +12 more
The chemically peculiar (CP) stars of the upper main sequence are excellent astrophysical laboratories to test the diffusion, mass-loss, rotational mixing, and pulsation in the (non-)presence of a stable local magnetic field. These processes are time-dependent. The age estimation of Galactic field stars suffers from several limitations. Therefore,…
Mining the time axis with TRON - II. MeerKAT detects a stellar radio flare from a distant RS CVn candidate
Tasse, C.; Heywood, I.; Oozeer, N. +14 more
Medium-time-scale (minutes to hours) radio transients are a relatively unexplored population. The wide field-of-view and high instantaneous sensitivity of instruments such as MeerKAT provides an opportunity to probe this class of sources, using image-plane detection techniques. The previous letter in this series describes our project and associate…
A possible misaligned orbit for the young planet AU Mic c
Aigrain, S.; Alonso, R.; Deleuil, M. +98 more
The AU Microscopii planetary system is only 24 Myr old, and its geometry may provide clues about the early dynamical history of planetary systems. Here, we present the first measurement of the Rossiter-McLaughlin effect for the warm sub-Neptune AU Mic c, using two transits observed simultaneously with the European Southern Observatory's (ESO's) Ve…
Direct N-body simulations of NGC 6397 and its tidal tails
Baumgardt, Holger; Arnold, Anthony D.
We have performed a series of direct N-body simulations that study the evolution of the Galactic globular cluster NGC 6397 under the combined influence of two-body relaxation, stellar evolution, and the Milky Way's tidal field. Our simulations follow the evolution of the cluster over the last several Gyr up to its present-day position in the Milky…
The GALAH Survey: Stellar parameters and abundances for 800 000 Gaia RVS spectra using GALAH DR4 and The Cannon
Lewis, Geraint F.; Casey, Andrew R.; Buder, Sven +15 more
Analysing stellar parameters and abundances from nearly one million Gaia Data Release 3 (DR3) Radial Velocity Spectrometer (RVS) spectra poses challenges due to the limited spectral coverage (restricted to the infrared Ca II triplet) and variable signal-to-noise ratios of the data. To address this, we use The Cannon, a data-driven method, to trans…
Constraining the scattered light properties of LTT 9779 b using HST/WFC3 UVIS
Wakeford, Hannah R.; Cowan, Nicolas B.; Parmentier, Vivien +5 more
A planet's albedo is a fundamental property that sets its energy budget by dictating the fraction of incident radiation absorbed versus reflected back to space. Generally, optical eclipse observations have revealed the majority of hot, giant planets to have low albedos, indicating dayside atmospheres dominated by absorption instead of reflection. …
On the origin of the Hercules group - I. Chemical signatures indicating the outer bar origin
Jerjen, Helmut; Buder, Sven; Freeman, Kenneth +3 more
The Hercules kinematic group is a kinematic anomaly of stars observed in the solar neighbourhood (SNd). In this series of papers, we present a comprehensive study of this structure. This paper focuses on its chemical signatures over several groups of elements. The next paper discusses its kinematical properties. While studies suggested a non-nativ…
The NCORES programme: precise planetary masses, null results, and insight into the planet mass distribution near the radius gap
Lester, Kathryn V.; Wheatley, Peter J.; Bayliss, Daniel +39 more
NCORES was a large observing programme on the ESO HARPS spectrograph, dedicated to measuring the masses of Neptune-like and smaller transiting planets discovered by the TESS satellite using the radial velocity technique. This paper presents an overview of the programme, its scientific goals and published results, covering 35 planets in 18 planetar…
Uniform characterization of an ensemble of main-sequence benchmark stars: effect of Gaia-based data on grid search models
Nsamba, Benard; Weiss, Achim; Kamulali, Juma
The inference of stellar parameters (such as radius and mass) through asteroseismic forward modelling depends on the number, accuracy, and precision of seismic and atmospheric constraints. ESA's Gaia space mission is providing precise parallaxes which yield an additional constraint to be included in the model grid search. Using a handful of main-s…
Serendipitous observation of a white dwarf companion to a JWST/MIRI coronagraphic calibrator
Boccaletti, Anthony; Blouin, Simon; Pearce, Logan A. +3 more
We present the unplanned detection of a white dwarf companion to the star HD 218261 in mid-infrared (10-16