Comparison between a Radiative Wind Model for be Stars and High Angular Resolution Data from the GI2T Interferometer

1995 ◽  
pp. 561-562
Author(s):  
Ph. Stee
Keyword(s):  
Angular Resolution ◽  
High Angular Resolution ◽  
Be Stars ◽  
Wind Model ◽  
Resolution Data

scholarly journals Michelson-Spectro-Interferometry (MSI) of Be stars envelopes with the GI2T Interferometer

1995 ◽  
Vol 149 ◽  
pp. 365-368
Author(s):  
Ph. Stee ◽  
D. Bonneau ◽  
P. Lawson ◽  
F. Morand ◽  
D. Mourard ◽  
...  
Keyword(s):  
Angular Resolution ◽  
Michelson Interferometer ◽  
Numerical Code ◽  
High Angular Resolution ◽  
Be Stars ◽  
Wind Model ◽  
Long Baseline ◽  
Balmer Lines ◽  
Extended Sources ◽  
Resolution Data

AbstractThe GI2T is an optical long-baseline Michelson interferometer which analyses dispersed stellar fringes in the multi-speckle mode with a spectral resolution of one Angstrom while the spatial resolution is about one milliarcsecond. This makes the GI2T a powerful instrument able to perform MSI of extended sources like Be stars or shell stars. In order to interpret these data we have developed a latitude dependent radiative wind model for Be stars. This numerical code enables us to compare directly computed 2D maps in some Balmer lines (Hα and Hβ) with high angular resolution data of some Be stars.

scholarly journals Herbig Ae/Be Star Disks at High Angular Resolution

2004 ◽  
Vol 221 ◽  
pp. 389-394
Author(s):  
C. P. Dullemond ◽  
C. Dominik ◽  
R. van Boekel ◽  
R. Waters ◽  
M. van den Ancker
Keyword(s):  
Angular Resolution ◽  
Protoplanetary Disks ◽  
Spectral Energy ◽  
High Angular Resolution ◽  
Be Stars ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Spatially Resolved ◽  
Be Star ◽  
Geometric Picture

We show that there exists a simple geometric picture for the geometries of protoplanetary disks around Herbig Ae/Be stars that explains the two main kinds of spectral energy distributions found for these objects, and that makes predictions that are qualitatively in agreement with currently available spatially resolved images and/or interferometric measurements. Also it qualitatively explains the phenomenon of UX Orionis variability.

scholarly journals The circumstellar discs of Be stars

2010 ◽  
Vol 6 (S272) ◽  
pp. 325-336 ◽  
Author(s):  
Alex C. Carciofi
Keyword(s):  
Angular Resolution ◽  
Central Star ◽  
High Angular Resolution ◽  
Be Stars ◽  
Keplerian Orbit ◽  
Physical Processes ◽  
Simple Description ◽  
Model Predictions ◽  
Mass Ejection ◽  
Very High

AbstractCircumstellar discs of Be stars are thought to be formed from material ejected from a fast-spinning central star. This material possesses large amounts of angular momentum and settles in a quasi-Keplerian orbit around the star. This simple description outlines the basic issues that a successful disc theory must address: 1) What is the mechanism responsible for the mass ejection? 2) What is the final configuration of the material? 3) How the disc grows? With the very high angular resolution that can be achieved with modern interferometers operating in the optical and infrared we can now resolve the photosphere and immediate vicinity of nearby Be stars. Those observations are able to provide very stringent tests for our ideas about the physical processes operating in those objects. This paper discusses the basic hydrodynamics of viscous decretion discs around Be stars. The model predictions are quantitatively compared to observations, demonstrating that the viscous decretion scenario is currently the most viable theory to explain the discs around Be stars.

Investigation of the Chromosphere–Corona Interface with the Upgraded Very High Angular Resolution Ultraviolet Telescope (VAULT2.0)

2016 ◽  
Vol 05 (01) ◽  
pp. 1640003 ◽  
Author(s):  
Angelos Vourlidas ◽  
Samuel Tun Beltran ◽  
Georgios Chintzoglou ◽  
Kevin Eisenhower ◽  
Clarence Korendyke ◽  
...  
Keyword(s):  
High Resolution ◽  
Angular Resolution ◽  
Solar Spectrum ◽  
High Angular Resolution ◽  
High Resolution Data ◽  
Lyman Alpha ◽  
And Performance ◽  
White Sands ◽  
Very High ◽  
Resolution Data

Very high angular resolution ultraviolet telescope (VAULT2.0) is a Lyman-alpha (Ly[Formula: see text]; 1216[Formula: see text]Å) spectroheliograph designed to observe the upper chromospheric region of the solar atmosphere with high spatial ([Formula: see text]) and temporal (8[Formula: see text]s) resolution. Besides being the brightest line in the solar spectrum, Ly[Formula: see text] emission arises at the temperature interface between coronal and chromospheric plasmas and may, hence, hold important clues about the transfer of mass and energy to the solar corona. VAULT2.0 is an upgrade of the previously flown VAULT rocket and was launched successfully on September 30, 2014 from White Sands Missile Range (WSMR). The target was AR12172 midway toward the southwestern limb. We obtained 33 images at 8[Formula: see text]s cadence at arc second resolution due to hardware problems. The science campaign was a resounding success, with all space and ground-based instruments obtaining high-resolution data at the same location within the AR. We discuss the science rationale, instrument upgrades, and performance during the first flight and present some preliminary science results.

scholarly journals Projections of Brodmann Area 6 to the Pyramidal Tract in Humans: Quantifications Using High Angular Resolution Data

2019 ◽  
Vol 13 ◽  
Author(s):  
Zhen-Ming Wang ◽  
Yi Shan ◽  
Miao Zhang ◽  
Peng-Hu Wei ◽  
Qiong-Ge Li ◽  
...  
Keyword(s):  
Angular Resolution ◽  
Pyramidal Tract ◽  
Brodmann Area ◽  
High Angular Resolution ◽  
Area 6 ◽  
Resolution Data

scholarly journals Interferometry and Stellar Magnetism

2000 ◽  
Vol 175 ◽  
pp. 174-177 ◽  
Author(s):  
O. Chesneau ◽  
K. Rousselet-Perraut ◽  
F. Vakili
Keyword(s):  
Spectral Resolution ◽  
Angular Resolution ◽  
Zeeman Effect ◽  
High Spectral Resolution ◽  
Sensitivity Threshold ◽  
High Angular Resolution ◽  
Be Stars ◽  
Long Baseline ◽  
Instrumental Polarisation ◽  
Very High

AbstractThe classical detection of magnetic fields in Be stars remains a challenge due to the sensitivity threshold and geometrical cancelation of the field effects. We propose to study the Zeeman effect using Spectro-Polarimetric INterferometry (SPIN) which consists of the simultaneous use of polarimetry and very high angular resolution provided by long baseline interferometers. As monitoring of the instrumental polarisation is mandatory in order to calibrate interferometric observations in any case, the polarised signal is a natural by-product of interferometers. This method will be tested on the GI2T interferometer thanks to its high spectral resolution and its polarimetric capabilities.

scholarly journals Physics of Radiatively Driven Winds by High Angular Resolution Observations (HARO)

1999 ◽  
Vol 169 ◽  
pp. 115-118
Author(s):  
Ph. Stee ◽  
D. Bonneau ◽  
D. Mourard ◽  
F. Vakili
Keyword(s):  
Energy Distribution ◽  
Line Profile ◽  
Angular Resolution ◽  
High Angular Resolution ◽  
Wind Model ◽  
Polarization Data ◽  
Hot Stars ◽  
B Stars ◽  
Continuum Energy

AbstractNumerous models have been developed during the last two decades which try to fit a small number of “classical” observables as closely as possible (i.e Hα line profile and continuum energy distribution or polarization data). Nevertheless, little has been done to include High Angular Resolution Observations (HARO) in simulations in spite of the fact that such data can strongly constrain radiative wind models. In the following, we shall review recent results coming from HARO of active B stars and we shall focus on our radiative wind model for active hot stars which integrates these measurements.

Direct Optical Imaging of Be Disks

2000 ◽  
Vol 175 ◽  
pp. 129-140
Author(s):  
Philippe Stee
Keyword(s):  
Optical Imaging ◽  
Spectral Resolution ◽  
Role Models ◽  
Angular Resolution ◽  
High Spectral Resolution ◽  
High Angular Resolution ◽  
Be Stars ◽  
Hot Stars ◽  
Time Consumption ◽  
Circumstellar Environment

AbstractInterferometry in the visible now provides milliarcsecond spatial resolution and thus can be used for studying the circumstellar environment of Be stars. In this review I will first introduce the two basic quantities that an interferometer can access: the modulus and the phase of the visibility. I will illustrate how these two quantities can be used to understand the physics of Be disks through recent results from the VLA, the MkII and the GI2T interferometers. I will insist on the importance and the potential of coupling high angular resolution with high spectral resolution to the study of Be disks. Since the possibility of direct optical imaging of Be disks will be limited due to complexity and time consumption, I will present the role models can play in interpreting high angular resolution observations when direct imaging become difficult. Finally I will draw up a list of challenging objectives for the next generation of synthetic arrays (GI2T/REGAIN, Keck, ST3, VLTI) which will bring new understanding of active hot stars physics.

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