TY  - JOUR
A1  - Pelisoli, Ingrid
A1  - Dorsch, Matti
A1  - Heber, Ulrich
A1  - Gänsicke, Boris
A1  - Geier, Stephan
A1  - Kupfer, Thomas
A1  - Nemeth, Peter
A1  - Scaringi, Simone
A1  - Schaffenroth, Veronika
T1  - Discovery and analysis of three magnetic hot subdwarf stars
T2  - Monthly notices of the Royal Astronomical Society
N2  - Magnetic fields can play an important role in stellar evolution. Among white dwarfs, the most common stellar remnant, the fraction of magnetic systems is more than 20 per cent. The origin of magnetic fields in white dwarfs, which show strengths ranging from 40 kG to hundreds of MG, is still a topic of debate. In contrast, only one magnetic hot subdwarf star has been identified out of thousands of known systems. Hot subdwarfs are formed from binary interaction, a process often associated with the generation of magnetic fields, and will evolve to become white dwarfs, which makes the lack of detected magnetic hot subdwarfs a puzzling phenomenon. Here we report the discovery of three new magnetic hot subdwarfs with field strengths in the range 300-500 kG. Like the only previously known system, they are all helium-rich O-type stars (He-sdOs). We analysed multiple archival spectra of the three systems and derived their stellar properties. We find that they all lack radial velocity variability, suggesting formation via a merger channel. However, we derive higher than typical hydrogen abundances for their spectral type, which are in disagreement with current model predictions. Our findings suggest a lower limit to the magnetic fraction of hot subdwarfs of 0.147(+0.143)(-0.047) per cent, and provide evidence for merger-induced magnetic fields which could explain white dwarfs with field strengths of 50-150 MG, assuming magnetic flux conservation.
KW  - stars: magnetic field
KW  - subdwarfs
Y1  - 2022
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/64169
SN  - 0035-8711
SN  - 1365-2966
VL  - 515
IS  - 2
SP  - 2496
EP  - 2510
PB  - Oxford University Press
CY  - Oxford
ER  -