Search Publications
[Mg/Fe] ratios in the solar neighbourhood: Stellar yields and chemical evolution scenarios
Recio-Blanco, Alejandra; Matteucci, Francesca; Palla, Marco +1 more
Context. The [Mg/Fe] abundance ratios are a fundamental fossil signature used to trace the chemical evolution of the disc and to divide it into low-α and high-α populations. Despite the huge observational and theoretical efforts, discrepancies between models and data are still present and several explanations have been put forward to explain the […
The VLT-FLAMES survey of massive stars. NGC 2004#115: A triple system hosting a possible short period B+BH binary
Dufton, P. L.; Lennon, D. J.; Monageng, I. M. +5 more
Context. NGC 2004#115 was classified as a single lined Be spectroscopic binary in the Large Magellanic Cloud. Its Hα morphology is reminiscent of the Galactic systems LB-1 and HR 6819, both of which are proposed as either Be+BH or Be+stripped He-star systems.
Aims: Multi-epoch optical spectra of NGC 2004#115 are used to determine if this bina…
Phase curve and geometric albedo of WASP-43b measured with CHEOPS, TESS, and HST WFC3/UVIS
Alonso, R.; Deleuil, M.; Erikson, A. +79 more
Context. Observations of the phase curves and secondary eclipses of extrasolar planets provide a window onto the composition and thermal structure of the planetary atmospheres. For example, the photometric observations of secondary eclipses lead to the measurement of the planetary geometric albedo, Ag, which is an indicator of the prese…
Localized thermonuclear bursts from accreting magnetic white dwarfs
Knigge, C.; de Martino, D.; Done, C. +16 more
Nova explosions are caused by global thermonuclear runaways triggered in the surface layers of accreting white dwarfs1-3. It has been predicted4-6 that localized thermonuclear bursts on white dwarfs can also take place, similar to type-I X-ray bursts observed in accreting neutron stars. Unexplained rapid bursts from the binar…
Radial velocity variability and the evolution of hot subdwarf stars
Geier, S.; Heber, U.; Irrgang, A. +3 more
Hot subdwarf stars represent a late and peculiar stage in the evolution of low-mass stars, since they are likely formed by close binary interactions. In this work, we perform a radial velocity (RV) variability study of a sample of 646 hot subdwarfs with multi-epoch radial velocities based on spectra from Sloan Digital Sky Survey (SDSS) and Large S…
Coronal condensation as the source of transition-region supersonic downflows above a sunspot
Tian, Hui; Peter, Hardi; Hou, Zhenyong +3 more
Context. Plasma loops or plumes rooted in sunspot umbrae often harbor downflows with speeds of 100 km s−1. These downflows are supersonic at transition region temperatures of ∼0.1 MK. The source of these flows is not well understood.
Aims: We aim to investigate the source of sunspot supersonic downflows (SSDs) in active region 1274…
LRG-BEASTS: Sodium absorption and Rayleigh scattering in the atmosphere of WASP-94A b using NTT/EFOSC2
Kirk, J.; Louden, T.; Wheatley, P. J. +3 more
We present an optical transmission spectrum for WASP-94A b, the first atmospheric characterization of this highly-inflated hot Jupiter. The planet has a reported radius of $1.72^{+0.06}_{-0.05}$ RJup, a mass of only $0.456^{+0.032}_{-0.036}$ MJup, and an equilibrium temperature of 1508 ± 75 K. We observed the planet transit s…
The eROSITA Final Equatorial-Depth Survey (eFEDS). The Stellar Counterparts of eROSITA sources identified by machine learning and Bayesian algorithms
Schmitt, J. H. M. M.; Salvato, M.; Czesla, S. +3 more
Stars are ubiquitous X-ray emitters and will be a substantial fraction of the X-ray sources detected in the on-going all-sky survey performed by the eROSITA instrument aboard the Spectrum Roentgen Gamma (SRG) observatory. We use the X-ray sources in the eROSITA Final Equatorial-Depth Survey (eFEDS) field observed during the SRG performance verific…
Systematic Korea Microlensing Telescope Network planetary anomaly search - III. One wide-orbit planet and two stellar binaries
Han, Cheongho; Udalski, Andrzej; Lee, Chung-Uk +36 more
Only a few wide-orbit planets around old stars have been detected, which limits our statistical understanding of this planet population. Following the systematic search for planetary anomalies in microlensing events found by the Korea Microlensing Telescope Network, we present the discovery and analysis of three events that were initially thought …
511 keV line constraints on feebly interacting particles from supernovae
Calore, Francesca; Carenza, Pierluca; Giannotti, Maurizio +4 more
Feebly interacting particles with masses with O (10 - 100 ) MeV can be copiously produced by core-collapse supernovae (SNe). In this paper we consider the case of MeV-ish sterile neutrinos and dark photons mixed with ordinary neutrinos and photons, respectively. Furthermore, both sterile neutrinos and dark photons may decay into positrons on their…