Search Publications
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…
Chandra and Magellan/FIRE follow-up observations of PSO167-13: An X-ray weak QSO at z = 6.515
Bauer, F. E.; Brandt, W. N.; Vignali, C. +19 more
Context. The discovery of hundreds of quasi-stellar objects (QSOs) in the first gigayear of the Universe powered by already grown supermassive black holes (SMBHs) challenges our knowledge of SMBH formation. In particular, investigations of z > 6 QSOs that present notable properties can provide unique information on the physics of fast SMBH grow…
CAPOS: The bulge Cluster APOgee Survey. II. The intriguing "Sequoia" globular cluster FSR 1758
Cohen, Roger E.; Beers, Timothy C.; Minniti, Dante +16 more
We present results from a study of 15 red giant members of the intermediate-metallicity globular cluster (GC) FSR 1758 using high-resolution, near-infrared spectra collected with the Apache Point Observatory Galactic Evolution Experiment II survey (APOGEE-2) that were obtained as part of CAPOS (the bulge Cluster APOgee Survey). Since its very rece…
Estimates of the change rate of solar mass and gravitational constant based on the dynamics of the Solar System
Pitjeva, E. V.; Pitjev, N. P.; Pavlov, D. A. +1 more
The estimate of the change rate of the solar gravitational parameter d(GM⊙)∕dt is obtained from processing modern positional observations of planets and spacecraft. Observations were processed and parameters were determined basing on the numerical planetary ephemeris EPM2019. The obtained annual decrease in solar mass M⊙ acco…
Evolution of anisotropic turbulence in the fast and slow solar wind: Theory and Solar Orbiter measurements
Fedorov, A.; Horbury, T. S.; Louarn, P. +8 more
Aims: Solar Orbiter (SolO) was launched on February 9, 2020, allowing us to study the nature of turbulence in the inner heliopshere. We investigate the evolution of anisotropic turbulence in the fast and slow solar wind in the inner heliosphere using the nearly incompressible magnetohydrodynamic (NI MHD) turbulence model and SolO measurements…
Parker Solar Probe observations of He/H abundance variations in SEP events inside 0.5 au
Mitchell, D. G.; McComas, D. J.; Bale, S. D. +24 more
Aims: The Parker Solar Probe (PSP) orbit provides an opportunity to study the inner heliosphere at distances closer to the Sun than previously possible. Due to the solar minimum conditions, the initial orbits of PSP yielded only a few solar energetic particle (SEP) events for study. Recently during the fifth orbit, at distances from 0.45 to 0…