S. P. Järvinen
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View article: The incidence of magnetism in blue and yellow straggler stars
The incidence of magnetism in blue and yellow straggler stars Open
Context . Our understanding of the generation of magnetic fields in intermediate-mass and massive OBA stars remains limited. Some theories have proposed that their magnetic fields could be a result of strong binary interactions, including …
View article: A magnetic tertiary in the most massive compact triple-star system
A magnetic tertiary in the most massive compact triple-star system Open
The system TIC 470710327 is comprised of three main-sequence OB stars, with an inner compact 1.10 d eclipsing binary and a non-eclipsing tertiary on a 52.04 d orbit. With the tertiary mass of 14.5–16 ${\rm M}_{\odot }$ and both components …
View article: Spectral Variability of Herbig Ae Star V1295, Aquila
Spectral Variability of Herbig Ae Star V1295, Aquila Open
This article presents the results of long-term spectral studies of the unusual Herbig Ae star V1295 Aql. The variability in the spectrophotometric parameters of the emission and absorption components of the hydrogen lines Hα, Hβ, and D Na …
View article: A search for Maunder-minimum candidate stars
A search for Maunder-minimum candidate stars Open
Context . Stars with very low levels of magnetic activity provide an opportunity for a more quantitative comparison with the Sun during its Maunder minimum. Aims . We employ spectra from the RAVE survey in a search for particularly low-act…
View article: The enigmatic magnetic field of the planet hosting Herbig Ae/Be star HD 169142
The enigmatic magnetic field of the planet hosting Herbig Ae/Be star HD 169142 Open
Context. Recent observations of the accretion disk around the Herbig Ae/Be star HD 169142 have revealed its complex and asymmetric morphology that indicates the presence of planets. The knowledge of the magnetic field structure in host sta…
View article: First snapshot of a magnetosphere around a Herbig Ae/Be star
First snapshot of a magnetosphere around a Herbig Ae/Be star Open
Context. The Herbig Ae/Be star HD 190073 is one of the very few magnetic Herbig Ae/Be stars for which close low-mass companions have been reported. Previously published magnetic field measurements indicated an annual change in the field co…
View article: Magnetic field of the roAp star KIC 10685175: Observations versus theory
Magnetic field of the roAp star KIC 10685175: Observations versus theory Open
Context . KIC 10685175 is a roAp star whose polar magnetic field is predicted to be 6 kG through a nonadiabatic axisymmetric pulsation theoretical model. Aims . In this work, we aim to measure the magnetic field strength of KIC 10685175 us…
View article: Magnetic massive stars: confirming the merger scenario for the magnetic field generation
Magnetic massive stars: confirming the merger scenario for the magnetic field generation Open
Magnetic fields are considered to be key components of massive stars, with a far-reaching impact on their evolution and ultimate fate. A magnetic mechanism was suggested for the collimated explosion of massive stars, relevant for long-dura…
View article: TESS Detections of Pulsations in Of?p Stars in the Magellanic Clouds
TESS Detections of Pulsations in Of?p Stars in the Magellanic Clouds Open
We used Transiting Exoplanet Survey Satellite observations to search for pulsations in six known Of?p stars in the Magellanic Clouds. We find evidence for pulsational variability in three Of?p stars: UCAC4 115-008604, OGLE SMC-SC6 237339, …
View article: TESS detections of pulsations in Of?p stars in the Magellanic Clouds
TESS detections of pulsations in Of?p stars in the Magellanic Clouds Open
We used TESS observations to search for pulsations in six known Of?p stars in the Magellanic Clouds. We find evidence for pulsational variability in three Of?p stars: UCAC4 115-008604, OGLE SMC-SC6 237339, and AzV 220. Two of them, UCAC4 1…
View article: Magnetic field of the roAp star KIC~10685175: observations versus theory
Magnetic field of the roAp star KIC~10685175: observations versus theory Open
KIC 10685175 is a roAp star whose polar magnetic field is predicted to be 6 kG through a non-adiabatic axisymmetric pulsation theoretical model. In this work, we aim to measure the magnetic field strength of KIC 10685175 using high-resolut…
View article: Extreme magnetic field modulus variability of the Bp star HD 57372
Extreme magnetic field modulus variability of the Bp star HD 57372 Open
Context . In chemically peculiar Ap/Bp stars with large-scale organised magnetic fields of simple centred dipole configuration, the ratio between the maximum and the minimum of the mean magnetic field modulus is on the order of 1.25. Value…
View article: Extreme Magnetic Field Modulus Variability of the Bp star HD 57372
Extreme Magnetic Field Modulus Variability of the Bp star HD 57372 Open
Context. In chemically peculiar Ap/Bp stars with large-scale organised magnetic fields with a simple centred dipole configuration, the ratio between the maximum and the minimum of the mean magnetic field modulus is of the order of 1.25. Va…
View article: Detection of extragalactic magnetic massive stars
Detection of extragalactic magnetic massive stars Open
Context. Studies of the magnetic characteristics of massive stars have recently received significant attention because they are progenitors of highly magnetised compact objects. Stars initially more massive than about 8 M ⊙ leave behind ne…
View article: Cover Picture: Astron. Nachr. 4/2024
Cover Picture: Astron. Nachr. 4/2024 Open
Variability of the H α emission line profile of the magnetic O‐type star HD 54897 over one decade, from 2014 to 2024. In the left panels, each profile is plotted with a different color as is indicated in the legend, showing the correspondi…
View article: Characterizing the dynamical magnetosphere of the extremely slowly rotating magnetic <scp>O9</scp>.7 V star <scp>HD</scp> 54879 using rotational modulation of the H<i>α</i> profile
Characterizing the dynamical magnetosphere of the extremely slowly rotating magnetic <span>O9</span>.7 V star <span>HD</span> 54879 using rotational modulation of the H<i>α</i> profile Open
The magnetic field in the O9.7 V star HD 54879 has been monitored for almost a decade. Spectropolarimetric observations reveal a rather strong mean longitudinal magnetic field that varies with a period of about 7.41 years. Observations in …
View article: Characterizing the dynamical magnetosphere of the extremely slowly rotating magnetic O9.7 V star HD 54879 using rotational modulation of the H $α$ profile
Characterizing the dynamical magnetosphere of the extremely slowly rotating magnetic O9.7 V star HD 54879 using rotational modulation of the H $α$ profile Open
The magnetic field in the O9.7 V star HD54879 has been monitored for almost a decade. Spectropolarimetric observations reveal a rather strong mean longitudinal magnetic field that varies with a period of about 7.41 yr. Observations in the …
View article: Testing pulsation diagnostics in the rapidly oscillating magnetic Ap star γ Equ using near-infrared CRIRES+ observations
Testing pulsation diagnostics in the rapidly oscillating magnetic Ap star γ Equ using near-infrared CRIRES+ observations Open
Context. Pulsations of rapidly oscillating Ap stars and their interaction with the stellar magnetic field have not been studied in the near-infrared (near-IR) region despite the benefits these observations offer compared to visual waveleng…
View article: The discovery space of ELT-ANDES. Stars and stellar populations
The discovery space of ELT-ANDES. Stars and stellar populations Open
The ArmazoNes high Dispersion Echelle Spectrograph (ANDES) is the optical and near-infrared high-resolution echelle spectrograph envisioned for the European Extremely Large Telescope (ELT). We present a selection of science cases, supporte…
View article: Searching for magnetic fields in pulsating A-type stars: the discovery of a strong field in the probable δ Sct star HD 340577 and a null result for the γ Dor star HR 8799
Searching for magnetic fields in pulsating A-type stars: the discovery of a strong field in the probable δ Sct star HD 340577 and a null result for the γ Dor star HR 8799 Open
Numerous δ Sct and γ Dor pulsators are identified in the region of the Hertzsprung–Russell diagram that is occupied by chemically peculiar magnetic Ap stars. The connection between δ Sct and γ Dor pulsations and the magnetic field in Ap st…
View article: The magnetic, spectroscopic, and photometric variability of the Wolf–Rayet star WR 55
The magnetic, spectroscopic, and photometric variability of the Wolf–Rayet star WR 55 Open
Studies of magnetic fields in the most evolved massive stars, the Wolf–Rayet stars, are of special importance because they are progenitors of certain types of supernovae. The first detection of a magnetic field of the order of a few hundre…
View article: Are magnetic fields universal in O-type multiple systems?
Are magnetic fields universal in O-type multiple systems? Open
Although significant progress has been achieved in recent surveys of the magnetism in massive stars, the origin of the detected magnetic fields remains to be the least understood topic in their studies. We present an analysis of 61 high-re…
View article: VPNEP: Detailed characterization of TESS targets around the Northern Ecliptic Pole
VPNEP: Detailed characterization of TESS targets around the Northern Ecliptic Pole Open
Context. We embarked on a high-resolution optical spectroscopic survey of bright Transiting Exoplanet Survey Satellite (TESS) stars around the Northern Ecliptic Pole (NEP), dubbed the Vatican-Potsdam-NEP (VPNEP) survey. Aims. Our NEP cover…
View article: Magnetic field measurements of sharp-lined Ap stars
Magnetic field measurements of sharp-lined Ap stars Open
Previous observations suggested that Ap and Bp stars exhibit a bimodal distribution of surface magnetic field strengths and that actually only few or no stars exist with magnetic dipole field strengths below 300 G down to a few Gauss. As t…
View article: The Magnetic Field of the Stripped Primary in the υ Sgr System, a Member of the Rare Class of Hydrogen-deficient Binaries
The Magnetic Field of the Stripped Primary in the υ Sgr System, a Member of the Rare Class of Hydrogen-deficient Binaries Open
We present the results of high-resolution spectropolarimetric observations of the optically dominant component in the rare hydrogen-deficient binary system υ Sgr. Only a small number of such systems in a very late phase of helium shell bur…
View article: Could the Magnetic Star HD 135348 Possess a Rigidly Rotating Magnetosphere?
Could the Magnetic Star HD 135348 Possess a Rigidly Rotating Magnetosphere? Open
We report the detection and characterization of a new magnetospheric star, HD 135348, based on photometric and spectropolarimetric observations. The TESS light curve of this star exhibited variations consistent with stars known to possess …
View article: Could the Magnetic Star HD 135348 Possess a Rigidly Rotating Magnetosphere?
Could the Magnetic Star HD 135348 Possess a Rigidly Rotating Magnetosphere? Open
We report the detection and characterization of a new magnetospheric star, HD 135348, based on photometric and spectropolarimetric observations. The TESS light curve of this star exhibited variations consistent with stars known to possess …
View article: Detection of anomalous element distribution in the extremely slowly rotating magnetic O9.7 V star HD 54879
Detection of anomalous element distribution in the extremely slowly rotating magnetic O9.7 V star HD 54879 Open
The O9.7 V star HD 54879 is currently the only massive magnetic star whose magnetic field geometry and rotation period are not constrained. Over the last 3 yr, we gathered additional observations of this star, obtained using various instru…
View article: Searching for Magnetospheres around Herbig Ae/Be Stars
Searching for Magnetospheres around Herbig Ae/Be Stars Open
We describe four different approaches for the detection of magnetospheric accretion among Herbig Ae/Be stars with accretion disks. Studies of several unique objects have been carried out. One of the objects is the Herbig Ae star HD 101412 …
View article: A detailed understanding of the rotation-activity relationship using the 300 Myr old open cluster NGC 3532
A detailed understanding of the rotation-activity relationship using the 300 Myr old open cluster NGC 3532 Open
Context. The coeval stars of young open clusters provide insights into the formation of the rotation-activity relationship that elude studies of multi-age field populations. Aims. We measure the chromospheric activity of cool stars in the …