M. Lundkvist
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Asteroseismic investigation of HD 140283: The Methuselah star Open
Context. HD 140283 is a well-studied metal-poor subgiant and a Gaia benchmark star, often used for testing stellar models due to its proximity, brightness, and low metallicity ([Fe/H]= − 2.3 dex). Aims. Here we present the first asteroseis…
Granulation signatures in 3D hydrodynamical simulations: Evaluating background model performance using a Bayesian nested sampling framework Open
Context. Understanding the granulation background signal is vital when interpreting the asteroseismic diagnostics of solar-like oscillators. Various descriptions exist throughout literature for modelling the surface manifestation of convec…
Asteroseismology of the G8 subgiant <i>β</i> Aquilae with SONG-Tenerife, SONG-Australia and TESS Open
Aims. We present time-series radial velocities of the G8 subgiant star β Aql obtained in 2022 and 2023 using SONG-Tenerife and, for the first time, SONG-Australia. We also analyse a sector of TESS photometry that overlapped with the 2022 S…
View article: K Dwarf Radius Inflation and a 10 Gyr Spin-down Clock Unveiled through Asteroseismology of HD 219134 from the Keck Planet Finder
K Dwarf Radius Inflation and a 10 Gyr Spin-down Clock Unveiled through Asteroseismology of HD 219134 from the Keck Planet Finder Open
We present the first asteroseismic analysis of the K3 V planet host HD 219134 based on four consecutive nights of radial velocities collected with the Keck Planet Finder. We apply Gold deconvolution to the power spectrum to disentangle mod…
View article: Pushing the boundaries of asteroseismic individual frequency modelling: Unveiling two evolved very low-metallicity red giants
Pushing the boundaries of asteroseismic individual frequency modelling: Unveiling two evolved very low-metallicity red giants Open
Context. Metal-poor stars play a crucial role in understanding the nature and evolution of the first stellar generation in the Galaxy. Previously, asteroseismic characterisation of red-giant stars has relied on constraints from the global …
View article: K-dwarf Radius Inflation and a 10-Gyr Spin-down Clock Unveiled through Asteroseismology of HD 219134 from the Keck Planet Finder
K-dwarf Radius Inflation and a 10-Gyr Spin-down Clock Unveiled through Asteroseismology of HD 219134 from the Keck Planet Finder Open
We present the first asteroseismic analysis of the K3\,V planet host HD~219134, based on four consecutive nights of radial velocities collected with the Keck Planet Finder. We applied Gold deconvolution to the power spectrum to disentangle…
The age of the Methuselah star in light of stellar evolution models with tailored abundances Open
Context. HD140283, or the Methuselah star, is a well-known reference object in stellar evolution. Its peculiar chemical composition, proximity and absence of reddening makes it an interesting case-study of Pop II stars. Thanks to recent ob…
The age of the Methuselah star in the light of stellar evolution models with tailored abundances Open
Context. HD140283, or the Methuselah star, is a well-known reference object in stellar evolution. Its peculiar chemical composition, proximity and absence of reddening makes it an interesting case-study of Pop II stars. Thanks to recent ob…
View article: The BANANA Project. VII. High Eccentricity Predicts Spin–Orbit Misalignment in Binaries
The BANANA Project. VII. High Eccentricity Predicts Spin–Orbit Misalignment in Binaries Open
The degree of spin–orbit alignment in a population of binary stars can be determined from measurements of their orbital inclinations and rotational broadening of their spectral lines. Alignment in a face-on binary guarantees low rotational…
Realising efficient computation of individual frequencies for red-giant models Open
Context. In order to improve the asteroseismic modelling efforts for red-giant stars, the numerical computation of theoretical individual oscillation modes for evolved red-giant models has to be made feasible. Aims. We aim to derive a meth…
Realising efficient computation of individual frequencies for red-giant models Open
In order to improve the asteroseismic modelling efforts for red-giant stars, the numerical computation of theoretical individual oscillation modes for evolved red-giant models has to be made feasible. We aim to derive a method for circumve…
View article: The BANANA Project. VII. High Eccentricity Predicts Spin-Orbit Misalignment in Binaries
The BANANA Project. VII. High Eccentricity Predicts Spin-Orbit Misalignment in Binaries Open
The degree of spin-orbit alignment in a population of binary stars can be determined from measurements of their orbital inclinations and rotational broadening of their spectral lines. Alignment in a face-on binary guarantees low rotational…
Low-amplitude Solar-like Oscillations in the K5 V Star ϵ Indi A Open
We have detected solar-like oscillations in the mid-K-dwarf ϵ Indi A, making it the coolest dwarf to have measured oscillations. The star is noteworthy for harboring a pair of brown dwarf companions and a Jupiter-type planet. We observed ϵ…
Low-amplitude solar-like oscillations in the K5 V star $\varepsilon$ Indi A Open
We have detected solar-like oscillations in the mid K-dwarf $\varepsilon$ Indi A, making it the coolest dwarf to have measured oscillations. The star is noteworthy for harboring a pair of brown dwarf companions and a Jupiter-type planet. W…
View article: Expanding the frontiers of cool-dwarf asteroseismology with ESPRESSO
Expanding the frontiers of cool-dwarf asteroseismology with ESPRESSO Open
Fuelled by space photometry, asteroseismology is vastly benefitting the study of cool main-sequence stars, which exhibit convection-driven solar-like oscillations. Even so, the tiny oscillation amplitudes in K dwarfs continue to pose a cha…
View article: A Hot Saturn Orbiting an Oscillating Late Subgiant Discovered by TESS
A Hot Saturn Orbiting an Oscillating Late Subgiant Discovered by TESS Open
We present the discovery of HD 221416 b, the first transiting planet identified by the Transiting Exoplanet Survey Satellite (TESS) for which asteroseismology of the host star is possible. HD 221416 b (HIP 116158, TOI-197) is a bright (V =…
View article: TESS Asteroseismic Analysis of HD 76920: The Giant Star Hosting an Extremely Eccentric Exoplanet
TESS Asteroseismic Analysis of HD 76920: The Giant Star Hosting an Extremely Eccentric Exoplanet Open
The Transiting Exoplanet Survey Satellite (TESS) mission searches for new exoplanets. The observing strategy of TESS results in high-precision photometry of millions of stars across the sky, allowing for detailed asteroseismic studies of i…
View article: TESS Asteroseismic Analysis of HD 76920: The Giant Star Hosting An Extremely Eccentric Exoplanet
TESS Asteroseismic Analysis of HD 76920: The Giant Star Hosting An Extremely Eccentric Exoplanet Open
The Transiting Exoplanet Survey Satellite (TESS) mission searches for new exoplanets. The observing strategy of TESS results in high-precision photometry of millions of stars across the sky, allowing for detailed asteroseismic studies of i…
View article: Radial velocity confirmation of a hot super-Neptune discovered by TESS with a warm Saturn–mass companion
Radial velocity confirmation of a hot super-Neptune discovered by TESS with a warm Saturn–mass companion Open
We report the discovery and confirmation of the planetary system TOI-1288. This late G dwarf harbours two planets: TOI-1288 b and TOI-1288 c. We combine TESS space-borne and ground-based transit photometry with HARPS-N and HIRES high-preci…
Radial velocity confirmation of a hot super-Neptune discovered by TESS with a warm Saturn-mass companion Open
We report the discovery and confirmation of the planetary system TOI-1288. This late G dwarf harbours two planets: TOI-1288 b and TOI-1288 c. We combine TESS space-borne and ground-based transit photometry with HARPS-N and HIRES high-preci…
View article: A 20 Second Cadence View of Solar-type Stars and Their Planets with TESS: Asteroseismology of Solar Analogs and a Recharacterization of π Men c
A 20 Second Cadence View of Solar-type Stars and Their Planets with TESS: Asteroseismology of Solar Analogs and a Recharacterization of π Men c Open
We present an analysis of the first 20 second cadence light curves obtained by the TESS space telescope during its extended mission. We find improved precision of 20 second data compared to 2 minute data for bright stars when binned to the…
TESS Asteroseismology of α Mensae: Benchmark Ages for a G7 Dwarf and Its M Dwarf Companion Open
Asteroseismology of bright stars has become increasingly important as a method to determine the fundamental properties (in particular ages) of stars. The Kepler Space Telescope initiated a revolution by detecting oscillations in more than …
View article: A 20-Second Cadence View of Solar-Type Stars and Their Planets with TESS: Asteroseismology of Solar Analogs and a Re-characterization of pi Men c
A 20-Second Cadence View of Solar-Type Stars and Their Planets with TESS: Asteroseismology of Solar Analogs and a Re-characterization of pi Men c Open
We present an analysis of the first 20-second cadence light curves obtained by the TESS space telescope during its extended mission. We find a precision improvement of 20-second data compared to 2-minute data for bright stars when binned t…
TESS Asteroseismology of $\alpha$ Mensae: Benchmark Ages for a G7 Dwarf and its M-dwarf Companion Open
Asteroseismology of bright stars has become increasingly important as a method to determine fundamental properties (in particular ages) of stars. The Kepler Space Telescope initiated a revolution by detecting oscillations in more than 500 …
The signature of granulation in a solar power spectrum as seen with <span>co5bold</span> Open
The granulation background seen in the power spectrum of a solar-like oscillator poses a serious challenge for extracting precise and detailed information about the stellar oscillations. Using a 3D hydrodynamical simulation of the Sun comp…
View article: Detection and Characterization of Oscillating Red Giants: First Results from the TESS Satellite
Detection and Characterization of Oscillating Red Giants: First Results from the TESS Satellite Open
Since the onset of the “space revolution” of high-precision high-cadence photometry, asteroseismology has been demonstrated as a powerful tool for informing Galactic archeology investigations. The launch of the NASA Transiting Exoplanet Su…
View article: The Orbital Eccentricity of Small Planet Systems
The Orbital Eccentricity of Small Planet Systems Open
We determine the orbital eccentricities of individual small Kepler planets, through a combination of asteroseismology and transit light-curve analysis. We are able to constrain the eccentricities of 51 systems with a single transiting plan…
A Hot Saturn Orbiting an Oscillating Late Subgiant Discovered by <i>TESS</i> Open
We present the discovery of HD 221416 b, the first transiting planet identified by the Transiting Exoplanet Survey Satellite (TESS) for which asteroseismology of the host star is possible. HD 221416 b (HIP 116158, TOI-197) is a bright (V =…
View article: An asteroseismic view of the radius valley: stripped cores, not born rocky
An asteroseismic view of the radius valley: stripped cores, not born rocky Open
Various theoretical models treating the effect of stellar irradiation on planetary envelopes predict the presence of a radius valley, i.e. a bimodal distribution of planet radii, with super-Earths and sub-Neptune planets separated by a val…