Search Publications
Upstream solar wind speed at comet 67P. Reconstruction method, model comparison, and results
Holmström, M.; Gunell, H.; Futaana, Y. +7 more
Context. Rosetta followed comet 67P at heliocentric distances from 1.25 to 3.6 au. The solar wind was observed for much of this time, but was significantly deflected and to some extent slowed down by the interaction with the coma.
Aims: We use the different changes in the speed of H+ and He2+ when they interact with the …
Short-timescale X-ray spectral variability in the Seyfert 1 galaxy NGC 3783
Kaastra, J. S.; Kriss, G. A.; Bianchi, S. +9 more
Aims: We report on the X-ray time-resolved spectral analysis of XMM-Newton observations of NGC 3783. Our main goal is to detect transient features in the Fe K line complex in order to study the dynamics of the innermost accretion flow.
Methods: We reanalyse archival observations of NGC 3783, a bright local active galactic nucleus, for wh…
Precision measurement of a brown dwarf mass in a binary system in the microlensing event. OGLE-2019-BLG-0033/MOA-2019-BLG-035
Bennett, D. P.; Bryden, G.; Soszyński, I. +94 more
Context. Brown dwarfs are transition objects between stars and planets that are still poorly understood, for which several competing mechanisms have been proposed to describe their formation. Mass measurements are generally difficult to carry out for isolated objects as well as for brown dwarfs orbiting low-mass stars, which are often too faint fo…
Quantification of O2 formation during UV photolysis of water ice: H2O and H2O:CO2 ices
Linnartz, H.; Chuang, K. -J.; Fedoseev, G. +4 more
Context. The Rosetta and Giotto missions investigated the composition of the cometary comae of 67P/Churyumov-Gerasimenko and 1P/Halley, respectively. In both cases, a surprisingly large amount of molecular oxygen (O2) was detected and was well correlated with the observed abundances of H2O. Laboratory experiments simulating c…
Development of a cometosheath at comet 67P/Churyumov-Gerasimenko. A case study comparison of Rosetta observations
Nilsson, H.; Goetz, C.; Stenberg Wieser, G. +2 more
Context. The ionosphere of a comet is known to deflect the solar wind through mass loading, but the interaction is dependent on cometary activity. We investigate the details of this process at comet 67P using the Rosetta Ion Composition Analyzer.
Aims: This study aims to compare the interaction of the solar wind and cometary ions during two d…
Close binary evolution based on Gaia DR2. The origin of late WC-type Wolf-Rayet stars with low luminosity
Meynet, Georges; Qin, Ying; Ekström, Sylvia +8 more
Context. The observed late-type WC Wolf-Rayet stars (WC7-9) with low luminosity below log L/L⊙ < 5.4 in the HR diagram cannot be reproduced satisfactorily by the evolutionary track of single stars. The mass transfer due to Roche lobe overflow drastically modifies the internal structure and surface compositions of two components. Ther…
Overexpansion-dominated coronal mass ejection formation and induced radio bursts
Song, H. Q.; Cheng, X.; Ding, M. D. +1 more
Aims: Coronal mass ejections (CMEs) are the most fascinating explosions in the Solar System. Their formation is still not fully understood, however.
Methods: We investigated a well-observed CME on 2021 May 7 that showed a typical three-component structure and was continuously observed from 0 to 3 R⊙ by a combination of SDO/AIA…
VVVX Near-IR Photometry for 99 Low-mass Stars in the Gaia EDR3 Catalog of Nearby Stars
Minniti, D.; Solano, E.; Saito, R. K. +3 more
Context. Red dwarf stars, which represent 75% of stars in the Milky Way, can be studied in great detail in the solar neighborhood, where the sample is more complete.
Aims: We intend to better characterize red-dwarf candidates selected from the Gαìα Catalog of Nearby Stars using optical and near-infrared multi-filter photometry from the Vista …
The spatial evolution of young massive clusters. III. Effect of the Gaia filter on 2D spatial distribution studies
Buckner, Anne S. M.; Khorrami, Zeinab; González, Marta +3 more
Context. With the third release of the high-precision optical-wavelength Gaia survey, we are in a better position than ever before to study young clusters. However, Gaia is limited in the optical down to G ∼ 21 mag, and therefore it is essential to understand the biases introduced by a magnitude-limited sample on spatial distribution studies.
…
A rare phosphorus-rich star in an eclipsing binary from TESS
Kama, Mihkel; Folsom, Colin P.; Eenmäe, Tõnis +6 more
Context. Few exoplanets around hot stars with radiative envelopes have been discovered, although new observations from the TESS mission are improving this. Stars with radiative envelopes have little mixing at their surface, and thus their surface abundances provide a sensitive test case for a variety of processes, including potentially star-planet…