Search Publications
Missions
Journals
Publication Years
A statistical approach to polarimetric and photometric investigation of the intermediate-age open cluster NGC 1912
Biswas, Samrat; Medhi, Biman J.; Deb, Sushmita +3 more
This paper presents a comprehensive multiwavelength investigation of the intermediate-age open cluster NGC 1912. We identified 401 member stars for NGC 1912 using K-nearest neighbour and Gaussian Mixture Model machine learning techniques. The fundamental parameters determined for the cluster are metallicity (z) = 0.0141 $\pm$ 0.0006, log(age) = 8.…
Inversion for Inferring Solar Meridional Circulation: The Case with Constraints on Angular Momentum Transport inside the Sun
Sekii, Takashi; Hotta, Hideyuki; Hatta, Yoshiki
We have carried out inversions of travel times as measured by Gizon et al. to infer the internal profile of the solar meridional circulation (MC). A linear inverse problem has been solved by the regularized least-squares method with a constraint that the angular momentum (AM) transport by MC should be equatorward (HK21-type constraint). Our motiva…
The AH Pictoris Syndrome: Continuous Trains of Stunted Outbursts in Novalike Variables
Bruch, Albert
Novalike variables are a subgroup of cataclysmic variables (CVs) that—unlike dwarf novae—do not exhibit strong brightenings in their long-term light curves. Variations over timescales of weeks, months, or years are mostly restricted to irregular low-amplitude modulations. However, some of them occasionally suffer from so-called stunted outbursts, …
New ephemerides and detection of transit-timing variations in the K2-138 system using high-precision CHEOPS photometry
Deleuil, M.; Hoyer, S.; Sulis, S. +5 more
Context. Multi-planet systems are a perfect laboratory for constraining planetary formation models. A few of these systems present planets that come very close to mean motion resonance, potentially leading to significant transit-timing variations (TTVs) due to their gravitational interactions. Of these systems, K2-138 represents an excellent labor…
Molecular Gas Tracers in Young and Old Protoplanetary Disks
Zhang, Ke; Cleeves, L. Ilsedore; Bergin, Edwin A. +6 more
Molecular emission is used to investigate both the physical and chemical properties of protoplanetary disks. Therefore, to derive disk properties accurately, we need a thorough understanding of the behavior of the molecular probes upon which we rely. Here we investigate how the molecular line emission of N2H+, HCO+…
Detection of the Actinide Th in an r-process-enhanced Star with Accretion Origin
Zhao, Gang; Li, Haining; Matsuno, Tadafumi +4 more
The thorium and six second-peak r-process element (56 ≤ Z ≤ 72) abundances are determined for the α-poor star LAMOST J1124+4535 based on a high-resolution spectrum obtained with the High Dispersion Spectrograph on the Subaru Telescope. The age of J1124+4535 is 11.3 ± 4.4 Gyr using thorium and other r-process element abundances. J1124+4535 is confi…
First detection of the [CII] 158 µm line in the intermediate-velocity cloud Draco
Ossenkopf-Okada, Volker; Simon, Robert; Klein, Bernd +7 more
High-latitude intermediate-velocity clouds (IVCs) are part of the Milky Way's H I halo and originate from either a galactic fountain process or extragalactic gas infall. They are partly molecular and can most of the time be identified in CO. Some of these regions also exhibit high-velocity cloud gas, which is mostly atomic, and gas at local veloci…
Ion-Acoustic Waves Associated With Interplanetary Shocks
Fedorov, A.; André, M.; Maksimovic, M. +10 more
Ion-acoustic waves (IAWs) commonly occur near interplanetary (IP) shocks. These waves are important because of their potential role in the dissipation required for collisionless shocks to exist. We study IAW occurrence statistically at different heliocentric distances using Solar Orbiter to identify the processes responsible for IAW generation nea…
Phase-resolved XMM-Newton observations of the massive post-RLOF system HD 149404
Rauw, G.; Rosu, S.; Mossoux, E. +1 more
Context. We investigated the X-ray emission of HD 149404, a 9.81-day period O-star binary in a post-Roche lobe overflow evolutionary stage. X-ray emission of O-star binaries consists of the intrinsic emission of the individual O stars and a putative additional component arising from the wind-wind interaction.
Aims: Phase-locked variations in …
Spatial distributions of extreme-ultraviolet brightenings in the quiet Sun
Barczynski, K.; Peter, H.; Müller, D. +16 more
Context. The identification of large numbers of localised transient extreme ultraviolet (EUV) brightenings, on very small spatial scales, in the quiet Sun corona has been one of the key early results from Solar Orbiter. However, there are still a great deal of unknowns about these events. Aims. In this work, we aim to better understand EUV brighte…