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 …
NGTS-19b: a high-mass transiting brown dwarf in a 17-d eccentric orbit
Jackman, James A. G.; Wheatley, Peter J.; Bayliss, Daniel +34 more
We present the discovery of NGTS-19b, a high-mass transiting brown dwarf discovered by the Next Generation Transit Survey. We investigate the system using follow-up photometry from the South African Astronomical Observatory, as well as sector 11 Transiting Exoplanet Survey Satellite data, in combination with radial velocity measurements from the C…
Classification of 4XMM-DR9 sources by machine learning
Wu, Xue-Bing; Zhang, Yanxia; Zhao, Yongheng
The ESA's X-ray Multi-mirror Mission (XMM-Newton) created a new high-quality version of the XMM-Newton serendipitous source catalogue, 4XMM-DR9, which provides a wealth of information for observed sources. The 4XMM-DR9 catalogue is correlated with the Sloan Digital Sky Survey (SDSS) DR12 photometric data base and the AllWISE data base; we then get…
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…
Cold Traps of Hypervolatiles in the Protosolar Nebula at the Origin of the Peculiar Composition of Comet C/2016 R2 (PanSTARRS)
Mousis, Olivier; Aguichine, Artyom; Bouquet, Alexis +4 more
Recent observations of the long-period comet C/2016 R2 (PanSTARRS; hereafter R2) indicate an unusually high N2/CO abundance ratio, typically larger than ∼0.05, and at least 2-3 times higher than the one measured in 67P/Churyumov-Gerasimenko. Another striking compositional feature of this comet is its heavy depletion in H2O (H…
The evolution of rapid optical/X-ray timing correlations in the initial hard state of MAXI J1820+070
Dhillon, V. S.; Charles, P. A.; Misra, R. +11 more
We report on a multiepoch campaign of rapid optical/X-ray timing observations of the superbright 2018 outburst of MAXI J1820+070, a black hole low-mass X-ray binary system. The observations spanned 80 d in the initial hard state and were taken with NTT/ULTRACAM and GTC/HiPERCAM in the optical (usgsrsisz<…
Variability, periodicity, and contact binaries in WISE
Zakamska, Nadia L.; Chandra, Vedant; Hwang, Hsiang-Chih +2 more
The time-series component of Wide-field Infrared Survey Explorer (WISE) is a valuable resource for the study of variable objects. We present an analysis of an all-sky sample of ~450 000 AllWISE+NEOWISE infrared light curves of likely variables identified in AllWISE. By computing periodograms of all these sources, we identify ~56 000 periodic varia…
Fomalhaut b could be massive and sculpting the narrow, eccentric debris disc, if in mean-motion resonance with it
Booth, Mark; Krivov, Alexander V.; Faramaz, Virginie +4 more
The star Fomalhaut hosts a narrow, eccentric debris disc, plus a highly eccentric companion Fomalhaut b. It is often argued that Fomalhaut b cannot have significant mass, otherwise it would quickly perturb the disc. We show that material in internal mean-motion resonances with a massive, coplanar Fomalhaut b would actually be long-term stable, and…
Multiwavelength Properties of Miras
Udalski, Andrzej; Szymański, Michał K.; Skowron, Jan +12 more
We comprehensively study the variability of Miras in the Large Magellanic Cloud by simultaneously analyzing light curves in 14 bands in the range of 0.5-24 µm. We model over 20 yr long, high-cadence I-band light curves collected by the Optical Gravitational Lensing Experiment (OGLE) and fit them to light curves collected in the remaining opt…