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The aim of this article is to demonstrate the useful role that can be played by spectropolarimetric observations of young and evolved emission line stars that analyse the linearly polarized component in their spectra. At the time of writing, this demonstration has to be made on the basis of optical data since there is no common-user infrared facility, in operation, that offers the desired combination of spectral resolution and sensitivity. Here we focus on what can be learned from linear spectropolarimetry alone at reasonably high spectral resolution and at $10^3 < $S/N$ < 10^4$. And we remind that the near infrared (1--2 micron) has the potential to out-perform the optical as a domain to work in because of the greatly reduced interstellar obscuration at these wavelengths. This point has been reached at a time when theory, exploiting flexible Monte Carlo methods, is fast becoming a powerful tool. In short we have the complex phenomena, and the rise of the modelling capability to match -- good data are the missing link.
Accretion is the prime mode of star formation, but the exact mode has not yet been identified in the Herbig Ae/Be mass range. We provide evidence that the the maximum variation in mass-accretion rate is reached on a rotational timescale, which sugges
Linear spectropolarimetry is a powerful tool to probe circumstellar structures on spatial scales that cannot yet be achieved through direct imaging. In this review I discuss the role that emission-line polarimetry can play in constraining geometrical
We reduced ESOs archival linear spectropolarimetry data (4000-9000AA) of 6 highly polarized and 8 unpolarized standard stars observed between 2010 and 2016, for a total of 70 epochs, with the FOcal Reducer and low dispersion Spectrograph (FORS2) moun
Using the HiVIS spectropolarimeter built for the Haleakala 3.7m AEOS telescope, we have obtained a large number of high precision spectropolarimetrc observations (284) of Herbig AeBe stars collected over 53 nights totaling more than 300 hours of obse
We present self-consistent models of gas in optically-thick dusty disks and calculate its thermal, density and chemical structure. The models focus on an accurate treatment of the upper layers where line emission originates, and at radii $gtrsim 0.7$