Direct observation of the radial magnetic field gradient in HD58260 from spectropolarimetry of NLTE lines in emission
arXiv:2111.06472 · doi:10.3847/1538-4357/ac36d6
Abstract
Because of the unquestionable presence of magnetic fields in stars, their role in the structure of stellar atmospheres has for a long time been a subject of speculation. In our contribution to this discussion we present spectropolarimetric evidence of the decrease of the radial component of the magnetic field with altitude in the atmosphere of HD58260, a B-type magnetic star on the main sequence. We show that the Stokes V profiles of metal lines in emission of the outer atmosphere are evidence for a field three times weaker than from absorption lines from inner layers. The extra flow of energetic particles due to the magnetic-gradient pumping mechanism could be at the origin of the magnetospheres surrounding this class of stars and at the basis of the high energy phenomena observed. We also list a series of spectral lines useful for measuring the surface field of early-type stars.
arXiv comment9 pages, 4 figures, 2 tables, to be published in ApJ
References in corpus (27)
- A Grid of NLTE Line-Blanketed Model Atmospheres of Early B-type Stars
- A Magnetic Confinement vs. Rotation Classification of Massive-Star Magnetospheres
- The MiMeS Survey of Magnetism in Massive Stars: Introduction and overview
- Mass loss in main-sequence B stars
- The Magnetic Early B-type Stars III: A main sequence magnetic, rotational, and magnetospheric biography
- The Magnetic Early B-type Stars I: Magnetometry and Rotation
- NGC 1624-2: A slowly rotating, X-ray luminous Of?cp star with an extraordinarily strong magnetic field
- XMM-Newton observations of the sigma Ori cluster. I. The complex RGS spectrum of the hot star sigma Ori AB
- A scaling relationship for non-thermal radio emission from ordered magnetospheres: from the top of the Main Sequence to planets
- NLTE line formation for Mg\ione\ and Mg\ii\ in atmospheres of B-A-F-G-K stars
- The Magnetic Early B-type Stars II: stellar atmospheric parameters in the era of Gaia
- Non-LTE line formation for Si I-II-III in A-B stars and the origin of Si II emission lines in iota Her
- NLTE carbon abundance determination in selected A- and B-type stars and the interpretation of C\ione\ emission lines
- Time-dependent atomic diffusion in the atmospheres of CP stars. A big step forward: introducing numerical models including a stellar mass loss
- Chemical diversity among A-B stars with low rotational velocities: non-LTE abundance analysis
- Emission Lines in the Spectrum of the 3He Star 3 Cen A
- Vertical magnetic field gradient in the photospheric layers of sunspots
- A JVLA survey of the high frequency radio emission of the massive magnetic B- and O-type stars
- The auroral radio emission of the magnetic B-type star rho OphC
- HST/STIS analysis of the first main sequence pulsar CU Vir
- Magnetic Gradient: A Natural Driver of Solar Eruptions
- A method to measure the transverse magnetic field and orient the rotational axis of stars
- The multi-line slope method for the measure of the effective magnetic field of the cool stars: an application to the solar like cycle of ε Eri
- Detection of magnetic fields in He-rich early B-type stars using HARPSpol
- Weak Metallic Emission Lines in Early B-Type Stars
- On the use of the first-order moment approach for measurements of H_eff from LSD profiles
- The NLTE Analyses of Carbon Emission Lines in the Atmospheres of O and B type Stars