Search Publications
How much large dust could be present in hot exozodiacal dust systems?
Krivov, A. V.; Ertel, S.; Wolf, S. +3 more
Context. An infrared excess over the stellar photospheric emission of main-sequence stars has been found in interferometric surveys, commonly attributed to the presence of hot exozodiacal dust (HEZD). While submicrometer-sized grains in close vicinity to their host star have been inferred to be responsible for the found near-infrared excesses, the…
Carte du Ciel and Gaia. I. Astrometry
Prusti, T.; Ness, J. -U.; Muinonen, K. +7 more
Context. The Carte du Ciel archive at the University of Helsinki enables us to see the sky as it was about 120 yr ago. The archive consists of single-exposure and triple-exposure plates between epochs 1896.8-1925.8.
Aims: Our main aim is to find binary and multiple stars by combining Carte du Ciel and Gaia data.
Methods: The plates were …
From binary to singular: The AGN PSO J334.2028+1.4075 under the high-resolution scope
Gurvits, L. I.; Ros, E.; An, T. +6 more
Context. PSO J334.2028+1.4075 (PSO J334) is a luminous quasar located at redshift z = 2.06. The source gained attention when periodic flux density variations were discovered in its optical light curve. These variations were initially interpreted as the variability due to the orbital motion of a supermassive black hole binary (SMBHB) residing in a …
The rotation period distribution in the young open cluster NGC 6709
Granzer, T.; Barnes, S. A.; Weingrill, J. +1 more
Open clusters serve as a useful tool for calibrating models of the relationship between mass, rotation, and age for stars with an outer convection zone due to the homogeneity of the stars within the cluster. Cluster-to-cluster comparisons are essential to determine whether the universality of spin-down relations holds.
The HARPS search for southern extra-solar planets. XLVII. Five Jupiter-mass planets in long-period orbits, one highly irradiated Neptune, one brown dwarf, and five stellar binaries
Bouchy, F.; Moutou, C.; Queloz, D. +10 more
Context. The long-term ongoing HARPS radial velocity survey of extra-solar planets initiated in 2003 provides a unique data set with a 19-yr baseline that allows the detection of long-period exoplanets, brown dwarfs, and low-mass binaries.
Aims: Our aim is to detect and characterise long-period companions around main sequence stars (spectral …
Concurrence of a Kelvin-Helmholtz instability and Kármán vortex street in the Sun's corona
Long, David M.; Fu, Hui; Li, Bo +4 more
Context. Instabilities are crucial to understanding the mass transportation and energy transformation in the solar atmosphere. Observations of the concurrence among the Kelvin-Helmholtz instability (KHI) and Kármán vortex street (KVS) in conditions as extreme as the Sun's corona have yet to be reported.
Aims: We aim to find evidence of a conc…
First r-process enhanced star confirmed as a member of the Galactic bulge
Schultheis, M.; Ryde, N.; Rich, R. M. +4 more
Aims: Stars with strong enhancements of r-process elements are rare and tend to be metal-poor, generally with [Fe/H] < −2 dex, and located in the halo. In this work, we aim to investigate a candidate r-process enriched bulge star with a relatively high metallicity of [Fe/H] ~ − 0.65 dex and to compare it with a previously published r-rich …
The Effelsberg survey of FU Orionis and EX Lupi objects. II. H2O maser observations
Menten, K. M.; Ábrahám, P.; Kóspál, Á. +7 more
Context. FU Orionis (FUor) and EX Lupi (EXor) type objects are two groups of peculiar and rare pre-main sequence low-mass stars that are undergoing powerful accretion outbursts during their early stellar evolution. Although water masers are widespread in star-forming regions and serve as powerful probes of mass accretion and ejection on small scal…
Systematics of planetary ephemeris reference frames inferred from pulsar timing astrometry
Liu, N.; Zhu, Z.; Liu, J. -C. +2 more
Aims: This study aims to investigate the systematic errors in planetary ephemeris reference frames through pulsar timing observations.
Methods: We used the published data sets from several pulsar timing arrays and performed timing analyses for each pulsar using different planetary ephemerides retrieved from the Jet Propulsion Laboratory'…
Transient obscuration event captured in NGC 3227. IV. Origin of the obscuring cloud variability
Kriss, G. A.; Bianchi, S.; Ebrero, J. +13 more
Context. Obscuration events in type I active galactic nuclei (AGN) have been detected more frequently in recent years. The strong flux decrease in the soft X-ray band between observations has been caused by clouds with large column densities transiting our line of sight (LOS) and covering the central AGN. Another event has been captured in NGC 322…