Search Publications
A homogeneous spectroscopic analysis of a Kepler legacy sample of dwarfs for gravity-mode asteroseismology
Li, Gang; Rix, Hans-Walter; Bowman, Dominic M. +12 more
Context. Asteroseismic modelling of the internal structure of main-sequence stars born with a convective core has so far been based on homogeneous analyses of space photometric Kepler light curves of four years in duration, to which most often incomplete inhomogeneously-deduced spectroscopic information was added to break degeneracies.
Aims: …
Whistler waves observed by Solar Orbiter/RPW between 0.5 AU and 1 AU
Maksimovic, M.; Bale, S. D.; Chust, T. +29 more
Context. Solar wind evolution differs from a simple radial expansion, while wave-particle interactions are assumed to be the major cause for the observed dynamics of the electron distribution function. In particular, whistler waves are thought to inhibit the electron heat flux and ensure the diffusion of the field-aligned energetic electrons (Stra…
PSP/IS⊙IS observations of the 29 November 2020 solar energetic particle event
Mitchell, D. G.; McComas, D. J.; Bale, S. D. +24 more
Aims: On 29 November 2020, at 12:34 UT, active region 12790 erupted with an M4.4 class flare and a 1700 km s−1 coronal mass ejection. Parker Solar Probe (PSP) was completing its seventh orbit around the Sun and was located at 0.8 au when the Integrated Science Investigation of the Sun (IS⊙IS) measured the ensuing mid-sized solar en…
Modeling the mixed-morphology supernova remnant IC 443. Origins of its complex morphology and X-ray emission
Miceli, M.; Bocchino, F.; Orlando, S. +4 more
Context. The morphology and the distribution of material observed in supernova remnants (SNRs) reflect the interaction of the supernova (SN) blast wave with the ambient environment, the physical processes associated with the SN explosion, and the internal structure of the progenitor star. IC 443 is a mixed-morphology (MM) SNR located in a quite co…
STIX X-ray microflare observations during the Solar Orbiter commissioning phase
Massa, Paolo; Krucker, Säm; Piana, Michele +34 more
Context. The Spectrometer/Telescope for Imaging X-rays (STIX) is the hard X-ray instrument onboard Solar Orbiter designed to observe solar flares over a broad range of flare sizes.
Aims: We report the first STIX observations of solar microflares recorded during the instrument commissioning phase in order to investigate the STIX performance at…
Machine learning initialization to accelerate Stokes profile inversions
Ruiz Cobo, B.; Quintero Noda, C.; Orozco Suárez, D. +3 more
Context. At present, an exponential growth in scientific data from current and upcoming solar observatories is expected. Most of the data consist of high spatial and temporal resolution cubes of Stokes profiles taken in both local thermodynamic equilibrium (LTE) and non-LTE spectral lines. The analysis of such solar observations requires complex i…
Sunspot tilt angles revisited: Dependence on the solar cycle strength
Jiang, Jie; Jiao, Qirong; Wang, Zi-Fan
Context. The tilt angle of sunspot groups is crucial in the Babcock-Leighton (BL) type dynamo for the generation of the poloidal magnetic field. Some studies have shown that the tilt coefficient, which excludes the latitudinal dependence of the tilt angles, is anti-correlated with the cycle strength. If the anti-correlation exists, it will be show…
Which Milky Way masses are consistent with the slightly declining 5-25 kpc rotation curve?
Hammer, F.; Jiao, Y.; Wang, J. L. +1 more
Context. Discoveries of extended rotation curves have suggested that spiral galaxy halos contain dark matter. This has led to many studies that estimated the total mass of the Galaxy, mostly using the Navarro, Frenk, and White (NFW) density profile.
Aims: We determine the effect that the choice of the dark matter profile has on the predicted …
A proto-helium white dwarf stripped by a substellar companion via common-envelope ejection. Uncovering the true nature of a candidate hypervelocity B-type star
Geier, S.; Heber, U.; Irrgang, A. +3 more
In the past, SDSS J160429.12+100002.2 wass spectroscopically classified as a blue horizontal branch (BHB) star. Assuming a luminosity that is characteristic of BHB stars, the object's radial velocity and proper motions from Gaia Early Data Release 3 would imply that its Galactic rest-frame velocity exceeds its local escape velocity. Consequently, …
GRAVITY K-band spectroscopy of HD 206893 B. Brown dwarf or exoplanet
Lutz, D.; Genzel, R.; Sturm, E. +93 more
Context. Near-infrared interferometry has become a powerful tool for studying the orbital and atmospheric parameters of substellar companions.
Aims: We aim to reveal the nature of the reddest known substellar companion HD 206893 B by studying its near-infrared colors and spectral morphology and by investigating its orbital motion.
Method…