Search Publications
Blue supergiants as tests for stellar physics
Meynet, Georges; Saio, Hideyuki; Georgy, Cyril
Context. Massive star evolution is still poorly understood, and observational tests are required to discriminate between different implementations of physical phenomena in stellar evolution codes.
Aims: By confronting stellar evolution models with observed properties of blue supergiants, such as pulsations, the chemical composition, and posit…
Evolutionary view through the starless cores in Taurus. Deuteration in TMC 1-C and TMC 1-CP
Ward-Thompson, D.; Kramer, C.; Fuente, A. +11 more
Context. The chemical and physical evolution of starless and pre-stellar cores are of paramount importance to understanding the process of star formation. The Taurus Molecular Cloud cores TMC 1-C and TMC 1-CP share similar initial conditions and provide an excellent opportunity to understand the evolution of the pre-stellar core phase.
Aims: …
Evidence for differentiation of the most primitive small bodies
Jorda, L.; Lamy, P.; Colas, F. +41 more
Context. Dynamical models of Solar System evolution have suggested that the so-called P- and D-type volatile-rich asteroids formed in the outer Solar System beyond Neptune's orbit and may be genetically related to the Jupiter Trojans, comets, and small Kuiper belt objects (KBOs). Indeed, the spectral properties of P- and D-type asteroids resemble …
Kinetic electrostatic waves and their association with current structures in the solar wind
Maksimovic, M.; Bale, S. D.; Chust, T. +21 more
Context. A variety of kinetic electrostatic and electromagnetic waves develop in the solar wind and the relationship between these waves and larger scale structures, such as current sheets and ongoing turbulence, remain a topic of investigation. Similarly, the instabilities producing ion-acoustic waves in the solar wind are still an open question.…
Capturing transient plasma flows and jets in the solar corona
Peter, H.; Chitta, L. P.; Solanki, S. K. +8 more
Intensity bursts in ultraviolet (UV) to X-ray wavelengths and plasma jets are typical signatures of magnetic reconnection and the associated impulsive heating of the solar atmospheric plasma. To gain new insights into the process, high-cadence observations are required to capture the rapid response of plasma to magnetic reconnection as well as the…
Asteroid spectral taxonomy using neural networks
Muinonen, K.; Penttilä, A.; Hietala, H.
Aims: We explore the performance of neural networks in automatically classifying asteroids into their taxonomic spectral classes. We particularly focus on what the methodology could offer the ESA Gaia mission.
Methods: We constructed an asteroid dataset that can be limited to simulating Gaia samples. The samples were fed into a custom-de…
Metallicities and ages for 35 star clusters and their surrounding fields in the Small Magellanic Cloud
Piatti, A. E.; Pych, W.; Narloch, W. +13 more
Aims: In this work we study 35 stellar clusters in the Small Magellanic Cloud (SMC) in order to provide their mean metallicities and ages. We also provide mean metallicities of the fields surrounding the clusters.
Methods: We used Strömgren photometry obtained with the 4.1 m SOAR telescope and take advantage of (b − y) and m1 colors for …
A new approach to spectroscopic phase curves. The emission spectrum of WASP-12b observed in quadrature with HST/WFC3
Désert, J. -M.; Stevenson, K. B.; Parmentier, V. +2 more
We analyse emission spectra of WASP-12b from a partial phase curve observed over three epochs with the Hubble Space Telescope, covering eclipse, quadrature, and transit, respectively. As the 1.1-day period phase curve was only partially covered over three epochs, traditional methods to extract the planet flux and instrument systematic errors canno…
Multiscale views of an Alfvénic slow solar wind: 3D velocity distribution functions observed by the Proton-Alpha Sensor of Solar Orbiter
André, N.; Fedorov, A.; Livi, S. +29 more
Context. The Alfvénic slow solar wind is of particular interest, as it is often characterized by intense magnetic turbulence, complex proton 3D velocity distribution functions (VDF), and an ensuing richness of kinetic and dynamic processes.
Aims: We take advantage of the fast time cadence of measurements taken by the Proton-Alpha Sensor (PAS)…
Fundamental properties of a selected sample of Ap stars: Inferences from interferometric and asteroseismic constraints
Keszthelyi, Z.; Cunha, M. S.; Holdsworth, D. L. +2 more
Context. Magnetic fields influence the formation and evolution of stars and impact the observed stellar properties. magnetic A-type stars (Ap stars) are a prime example of this. Access to precise and accurate determinations of their stellar fundamental properties, such as masses and ages, is crucial to understand the origin and evolution of fossil…