Related papers: Magnetic fields around late-type stars using water…
We study the polarization of the SiO maser emission in a representative sample of evolved stars in order to derive an estimate of the strength of the magnetic field, and thus determine the influence of this magnetic field on evolved stars.…
We present the results of MERLIN polarization mapping of OH masers at 1665 and 1667 MHz towards the Cepheus A star-forming region. The maser emission is spread over a region of 6 arcsec by 10 arcsec, twice the extent previously detected. In…
We present our past and current long-term monitoring program of water masers in the circumstellar envelopes of evolved stars, augmented by occasional interferometric observations. Using as example the Mira-variable U Her, we identify three…
In order to complete the knowledge of the magnetic field and of its influence during the transition from Asymptotic Giant Branch to Planetary Nebulae stages, we have undertaken a search for magnetic fields at the surface of Mira stars. We…
We present the largest sample of high-mass star-forming regions observed using submillimetre imaging polarimetry. The data were taken using SCUBA in conjunction with the polarimeter on the JCMT in Hawaii. In total, 16 star forming regions…
Over the last decade, large-scale, organized (generally dipolar) magnetic fields with a strength between 0.1 and 20 kG were detected in dozens of OB stars. This contribution reviews the impact of such magnetic fields on the stellar winds of…
Observational evidence for strong magnetic fields throughout the envelopes of evolved stars is increasing. Many of the instruments coming on line in the near-future will be able to make further contributions to this field. Specifically,…
Most of PNe are not spherical. The loss of spherical symmetry occurs somewhere between the AGB and PN phase. The cause of this change of morphology is not yet well known, but magnetic fields are one of the possible agents. Its origin…
We present Submillimeter Array observations of high frequency SiO masers around the supergiant VX Sgr and the semi-regular variable star W Hya. The J=5-4, v=1 28SiO and v=0 29SiO masers of VX Sgr are shown to be highly linearly polarized…
We report on the status of our spectropolarimetric studies of Herbig Ae/Be stars carried out during the last years. The magnetic field geometries of these stars, investigated with spectropolarimetric time series, can likely be described by…
We present initial results of a project to measure mean longitudinal magnetic fields in a group of sdB/OB/O stars. The project was inspired by the discovery of three super-metal-rich sdOB stars, each having metals (e.g. Ti, V) enhanced by…
We report full polarimetric VLBA observations of water masers towards the Turner-Welch Object in the W3(OH) high-mass star forming complex. This object drives a synchrotron jet, which is quite exceptional for a high-mass protostar, and is…
The relationship between the magnetic field and the circular polarization of astrophysical maser radiation due to the Zeeman effect under idealized conditions is investigated when the Zeeman splitting is much smaller than the spectral…
Basic aspects of the relationship between the magnetic field and polarized maser radiation are described with the emphasis on interpreting the observed spectra. Special attention is given to three issues--the limitations on the…
Magnetic fields have only recently been included in theoretical simulations of high-mass star formation. The simulations show that magnetic fields can play a crucial role not only in the formation and dynamics of molecular outflows, but…
Direct measurements of magnetic fields in low-mass stars of spectral class M have become available during the last years. This contribution summarizes the data available on direct magnetic measurements in M dwarfs from Zeeman analysis in…
In massive stars, magnetic fields are thought to confine the outflowing radiatively-driven wind, resulting in X-ray emission that is harder, more variable and more efficient than that produced by instability-generated shocks in non-magnetic…
Massive stars ($M > 8$ \msun) typically form in parsec-scale molecular clumps that collapse and fragment, leading to the birth of a cluster of stellar objects. We investigate the role of magnetic fields in this process through dust…
Late-type stars in general possess complicated magnetic surface fields which makes their detection and in particular their modeling and reconstruction challenging. In this work we present a new Zeeman-Doppler imaging code which is…
Maser emission from the SiO molecule has been widely observed in the near-circumstellar envelopes of late-type, evolved stars. VLBI images can resolve individual SiO maser spots, providing information about the kinematics and magnetic field…