Search Publications
Precise radial velocities of giant stars. XII. Evidence against the proposed planet Aldebaran b
Trifonov, Trifon; Stock, Stephan; Reffert, Sabine +2 more
Context. Radial-velocity variations of the K giant star Aldebaran (α Tau) were first reported in the early 1990s. After subsequent analyses, the radial-velocity variability with a period of ∼629 d has recently been interpreted as caused by a planet of several Jovian masses.
Aims: We want to further investigate the hypothesis of an extrasolar …
Dust-to-gas Ratio Resurgence in Circumstellar Disks Due to the Formation of Giant Planets: The Case of HD 163296
Marzari, F.; Testi, L.; Polychroni, D. +1 more
The amount of dust present in circumstellar disks is expected to steadily decrease with age due to the growth from µm-sized particles to planetesimals and planets. Mature circumstellar disks, however, can be observed to contain significant amounts of dust and possess high dust-to-gas ratios. Using HD 163296 as our case study, we explore how …
Seismic modelling of early B-type pulsators observed by BRITE - I. θ Ophiuchi
Moffat, Anthony F. J.; Pablo, Herbert; Walczak, Przemysław +8 more
We analyse time-series observations from the BRITE-Constellation of the well-known β Cephei type star θ Ophiuchi. Seven previously known frequencies were confirmed and 19 new frequency peaks were detected. In particular, high-order g modes, typical for the SPB (Slowly Pulsating B-type star) pulsators, are uncovered. These low-frequency modes are a…
A search for gravitationally lensed quasars and quasar pairs in Pan-STARRS1: spectroscopy and sources of shear in the diamond 2M1134-2103
Fassnacht, Christopher D.; Chen, Geoff C. -F.; Nelson, George J. +4 more
We present results of a systematic search for gravitationally lensed quasars in Pan-STARRS1. Our final sample of candidates comprises of 91 systems, not including 25 rediscovered lensed quasars and quasar pairs. In the absence of spectroscopy to verify the lensing nature of the candidates, the main sources of contaminants are likely to be quasar p…
Cassini-VIMS observations of Saturn's main rings: II. A spectrophotometric study by means of Monte Carlo ray-tracing and Hapke's theory
Clark, R. N.; Nicholson, P. D.; D'Aversa, E. +9 more
This work is the second in a series of manuscripts devoted to the investigation of the spectrophotometric properties of Saturn's rings from Cassini-VIMS (Visible and Infrared Mapping Spectrometer) observations. The dataset used for this analysis is represented by ten radial spectrograms of the rings which have been derived in Filacchione et al. (2…
Resolved scaling relations and metallicity gradients on sub-kiloparsec scales at z ≈ 1
Mahler, G.; Richard, J.; Nanayakkara, T. +9 more
The existence of a spatially resolved star-forming main sequence (rSFMS) and a spatially resolved mass-metallicity relation (rMZR) is now well established for local galaxies. Moreover, gradients with metallicity decreasing with radius seem to be common in local disc galaxies. These observations suggest that galaxy formation is a self-regulating pr…
CMEs in the Heliosphere: II. A Statistical Analysis of the Kinematic Properties Derived from Single-Spacecraft Geometrical Modelling Techniques Applied to CMEs Detected in the Heliosphere from 2007 to 2017 by STEREO/HI-1
Rodriguez, L.; Möstl, C.; Kilpua, E. K. J. +10 more
Recent observations with the Heliospheric Imagers (HIs) onboard the twin NASA Solar Terrestrial Relations Observatory (STEREO) spacecraft have provided unprecedented observations of a large number of coronal mass ejections (CMEs) in the inner heliosphere. In this article we discuss the generation of the HIGeoCAT CME catalogue and perform a statist…
Interstellar polarization and extinction in the Local Bubble and the Gould Belt
Gontcharov, George A.; Mosenkov, Aleksandr V.
We analyse an all-sky compilation of 13 data sources with optical interstellar linear polarization for 3871 Gaia DR2 and Hipparcos stars within 500 pc, which do not exhibit a considerable intrinsic polarization. These data are analysed together with five 3D maps and models of the reddening E(B - V). We consider variations of the polarization degre…
Local Manifestations of Cometary Activity
Keller, Horst Uwe; Skorov, Yuri; Vincent, Jean-Baptiste +5 more
Comets are made of volatile and refractory material and naturally experience various degrees of sublimation as they orbit around the Sun. This gas release, accompanied by dust, represents what is traditionally described as activity. Although the basic principles are well established, most details remain elusive, especially regarding the mechanisms…
Effects of the solar wind and the solar EUV flux on O+ escape rates from Venus
Fedorov, A.; Barabash, S.; Futaana, Y. +4 more
We investigate dependences of O+ escape rates from Venus both on the solar wind and the solar extreme ultraviolet (EUV) flux by using the 8.5-year dataset (May 2006 to December 2014) of the Ion Mass Analyzer and the magnetometer aboard Venus Express. We examine the O+ escape rates for 8 different conditions depending on the s…