Related papers: High angular resolution near-ultraviolet polarizat…
The near-star environment around obscured stars is very dynamic. Many classes of stars show evidence for winds, disks, inflows and outflows with many phenomena occurring simultaneously. These processes are involved in stellar evolution,…
Herbig Ae/Be objects are pre-main sequence stars surrounded by gas- and dust-rich circumstellar discs. These objects are in the throes of star and planet formation, and their characterisation informs us of the processes and outcomes of…
The polarization of light across individual spectral lines contains information about the circumstellar environment on very small spatial scales. We have obtained a large number of high precision, high resolution spectropolarimetric…
We present the results of HST/STIS and WFPC2 observations of LkHa 233 and its environment. LkHa233 is a Herbig Ae/Be star with a collimated bipolar jet. We investigate optical forbidden lines along the LkHa 233 jet to determine physical…
Inner regions of protoplanetary disks host many complex physical processes such as star-disk interactions, magnetic fields, planet formation, and the migration of new planets. To directly study this region requires milli-arcsecond angular…
The geometrical relationship between the distribution of circumstellar matter, observed optical linear polarization, outflows and binary orbital plane in Herbig Ae/Be stars is investigated. Optical linear polarization measurements carried…
We present H-band VLT/NACO polarized light images of the Herbig Ae/Be star HD169142 probing its protoplanetary disk as close as ~0.1" to the star. Our images trace the face-on disk out to ~1.7" (~250 AU) and reveal distinct sub-structures…
We have used laser guide star adaptive optics and a near-infrared dual-channel imaging polarimeter to observe light scattered in the circumstellar environment of Herbig Ae/Be stars on scales of 100-300 AU. We discover a strongly polarized,…
H_alpha spectropolarimetry on Herbig Ae/Be stars shows that the innermost regions of intermediate mass (2 -- 15 M_sun) Pre-Main Sequence stars are flattened. This may be the best evidence to date that the higher mass Herbig Be stars are…
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…
We present Halpha spectropolarimetry observations of a sample of 23 Herbig Ae/Be stars. A change in the linear polarisation across Halpha is detected in a large fraction of the objects, which indicates that the regions around Herbig stars…
In order to look for signs of on-going planet formation in young disks, we carried out the first J-band polarized emission imaging of the Herbig Ae/Be stars HD 150193, HD 163296, and HD 169142 using the Gemini Planet Imager (GPI), along…
The Herbig Ae/Be star LkHalpha 101 has been imaged at high angular resolution at a number of wavelengths in the near-infrared (from 1 to 3 microns) using the Keck 1 Telescope, and also observed in the mid-infrared (11.15 microns) using the…
The innermost astronomical unit in protoplanetary disks is a key region for stellar and planet formation, as exoplanet searches have shown a large occurrence of close-in planets that are located within the first au around their host star.…
We measured mid-infrared polarization of protoplanetary discs to gain new insight into their magnetic fields. Using CanariCam at the 10.4 m Gran Telescopio Canarias, we detected linear polarization at 8.7, 10.3, and 12.5 $\mu$m from discs…
Planet formation has been known for many years to be tied to the spatial distribution of gas and dust in disks around young stars. To constrain planet formation models, imaging observations of protoplanetary disks are required. In this…
This is the first in a series of papers in which we describe and report the analysis of a large survey of Herbig Ae/Be stars in circular spectropolarimetry. Using the ESPaDOnS and Narval high-resolution spectropolarimeters at the…
Context. It is now generally accepted that the near-infrared excess of Herbig AeBe stars originates in the dust of a circumstellar disk. Aims. The aims of this article are to infer the radial and vertical structure of these disks at scales…
The majority of the pre-main-sequence Herbig Ae/Be stars reside in binary systems. As these systems are young, their properties may contain an imprint of the star formation process at intermediate masses. However, these systems are…
We present a near-infrared $H$ band polarimetric study toward the S235 e2s3 protostar, obtained using the POLICAN instrument on the 2.1m OAGH telescope. The images reveal a bipolar outflow with a total length of about 0.5pc. The outflow…