Latest News

Magneto-Archeology of White Dwarfs: Discovering a magnetic pathway from red-giant cores to cold white dwarfs

Newly accepted A&A Letter to the Editor: Einramhof+ 2026 !

The detection of strong, large-scale magnetic fields at the surface of mainly the oldest population of white dwarfs points towards a hidden internal magnetic field slowly rising to the surface. We revisit the fossil field framework by using the asteroseismic detections to constrain the strength of such magnetic fields as they evolve to the white dwarf stage. We find that a broadly magnetized internal radiative zone during the red giant branch is key for the fossil field theory to connect magnetic fields observed along the late evolution of stars.

A new asymptotic expression for near degeneracy effects

New article from B. Liagre, A. Desai, L. Einramhof, & L. Bugnet accepted in A&A!

Quadrupolar (ℓ= 2) mixed modes contain information on the internal dynamics, but are very rarely characterised due to their low amplitude and the challenging identification of adjacent or overlapping rotationally split multiplets affected by near-degeneracy effects. We aim to extend broadly used asymptotic seismic diagnostics beyond ℓ= 1 mixed modes by developing an analogue asymptotic description of ℓ= 2 mixed modes, explicitly accounting for near-degeneracy effects that distort their rotational multiplets. We derive a new asymptotic formulation of near-degenerate mixed ℓ= 2 modes that describes off-diagonal terms representing the interaction between modes of adjacent radial orders. We are able to asymptotically model the asymmetric rotational splitting present in various radial orders of ℓ= 2 modes observed in young red giant stars without the need for any numerical stellar modelling.

New Role: Associate Editor for Stellar Physics at A&A

Lisa Bugnet becomes Associate Editor for Stellar Physics for the Journal A&A

Welcome Armand!

Armand Leclerc is joining Asterics as a Postdoctoral Researcher!

Welcome Nicolas!

Nicolas Muntean is joining ISTA as a PhD student!

Welcome Lynn!

Lynn Buchele is joining Asterics as a Postdoctoral researcher!

2 PhD Fellowships for Lucas Barrault!

Winner of the Austrian Academy of Sciences and the Gesellschaft für Forschungsförderung NÖ PhD Fellowships

New article: a way to detect core magnetism in γ-Dor stars

The inertial dip in the period-spacing pattern of fast rotating γ-Dor stars results from the interaction of core and envelope modes. As such, it gives an unprecedented window on the convective core structure and dynamics. In this article, we build a theoretical framework enabling the analysis of the inertial dip's sensitivity to magnetism.

TASC9/KASC16: Abstract submission and early registration Deadlines

2 May 2025: Deadline for contributed talk abstracts. Submit your abstract here.

26 May 2025: Early registration payment closes. Register here. Deadline for (physical) poster abstracts. Submit your abstract here.

In-person registration will be closed once the limit of 200 participants is reached. We recommend that you do not wait until the deadline to register, as the list of participants is already substantial, and we may have to close registration early.

For more details, please visit: https://tasc9-kasc16.ista.ac.at/

First Announcement:
TASC9/KASC16 Asteroseismic Science Consortium Workshop @Austria

This is the first announcement of the TASC9/KASC16 Workshop, taking place July 7-11 2025 at ISTA!
https://tasc9-kasc16.ista.ac.at

New Article! Core-to-envelope rotation in γDor stars

We show that increasing the convective core rotation with respect to the near-core rotation leads to a shift of the period of the observed dip to lower periods. In addition, the dip gets deeper and thinner as the convective core rotation increases. We demonstrate that such a signature is detectable in Kepler data, given appropriate dip parameter ranges and near-core structural properties.

ERC Starting Grant Calcifer Funded!

ERC Starting Grant Calcifer is now funded, and will explore the effects of magnetic fields on stellar evolution! Stay tuned for Postdoctoral and PhD opportunities.

Probing magnetic field Geometries

We investigate the detectability of complex magnetic field topologies (as the ones observed at the surface of stars with a radiative envelope with spectropolarimetry) inside the radiative interior of red giants. We focus on a field composed of a combination of a dipole and a quadrupole (quadrudipole), and on an offset field. We explore the potential of probing such magnetic field topologies from a combined measurement of magnetic signatures on l = 1 and quadrupolar (l = 2) mixed mode oscillation frequencies.

New article in ApJ

Using general Lorentz-stress (magnetic) kernels, we investigated the potential for detectability of near-surface magnetism in a 1.3M⊙ star of super-solar metallicity as it evolves from a mid sub-giant to a late sub-giant into an RG. Based on these sensitivity kernels, we decompose an RG into three zones — deep core, H-shell, and near-surface. The sub-giants instead required decomposition into an inner core, an outer core, and a near-surface layer. Additionally, we find that for a low-frequency g-dominated dipolar mode in the presence of a typical stable magnetic field, ∼25% of the frequency shift comes from the H-shell and the remaining from deeper layers.

ORF Regionales | Niederösterreich heute

TV interview!

Wiener Zeitung | Österreichs jüngste Professorin blickt in die Sterne

Newspaper article

New Letter to the editor in A&A

We investigate the ability of the observed asymmetries of the frequency splittings of dipolar mixed modes to constrain the geometrical properties of deep magnetic fields.

First Astrophysics Professor at ISTA

This is the beginning on the Asterics group at ISTA! Stay tuned for opportunities