Near-infrared speckle interferometry of evolved stars and bipolar nebulae

1984 ◽  
Vol 287 ◽  
pp. 801 ◽  
Author(s):  
H. M. Dyck ◽  
B. Zuckerman ◽  
Ch. Leinert ◽  
S. Beckwith
Keyword(s):  
Near Infrared ◽  
Speckle Interferometry ◽  
Evolved Stars

scholarly journals High-resolution near-infrared speckle interferometry and radiative transfer modeling of the OH/IR star OH 104.9+2.4

2004 ◽  
Vol 424 (1) ◽  
pp. 165-177 ◽  
Author(s):  
D. Riechers ◽  
Y. Balega ◽  
T. Driebe ◽  
K.-H. Hofmann ◽  
A. B. Men'shchikov ◽  
...  
Keyword(s):  
High Resolution ◽  
Radiative Transfer ◽  
Near Infrared ◽  
Speckle Interferometry ◽  
Radiative Transfer Modeling

scholarly journals A Two-Dimensional Near—Infrared Speckle Imaging Survey of T Tauri Stars in Taurus and Ophiuchus

1992 ◽  
Vol 135 ◽  
pp. 1-9
Author(s):  
A. Ghez ◽  
G. Neugebauer ◽  
K. Matthews
Keyword(s):  
Binary Stars ◽  
Near Infrared ◽  
Angular Separation ◽  
Speckle Interferometry ◽  
T Tauri Stars ◽  
Two Dimensional ◽  
Star Forming ◽  
Double Stars ◽  
Star Forming Regions ◽  
T Tauri

AbstractWe present the results of a magnitude limited (K≤8.5 mag) multiplicity survey of T Tauri stars in the two nearest star forming regions, Taurus-Auriga and Ophiuchus-Scorpius (D = 150 pc), observable from the northern hemisphere. Each of the 70 stars in the sample was imaged at 2.2 μm using two-dimensional speckle interferometry resulting in a survey sensitive to binary stars with separations ranging from 0.″09 to about 2″.5.The frequency of double stars with separation in this range is 46±8%. A division between the classical T Tauri stars and the weak-lined T Tauri stars shows no distinction. Furthermore, no difference is observed between the binary frequencies in the two star forming regions although the clouds have very different properties.Given the limited angular separation range that this survey is sensitive to, both the spectroscopic and wide binaries will be missed. The rate at which binaries are detected suggests that most, if not all, T Tauri stars have companions.

scholarly journals Near-Infrared Stellar Populations in the metal-poor, Dwarf irregular Galaxies Sextans A and Leo A

2018 ◽  
Vol 14 (S343) ◽  
pp. 429-430
Author(s):  
Olivia C. Jones ◽  
Matthew T. Maclay ◽  
Martha L. Boyer ◽  
Margaret Meixner ◽  
Iain McDonald
Keyword(s):  
Near Infrared ◽  
Infrared Camera ◽  
Stellar Populations ◽  
Asymptotic Giant Branch ◽  
Evolved Stars ◽  
Irregular Galaxies ◽  
Tentative Evidence ◽  
Period Variable ◽  
Red Giant ◽  
Dwarf Irregular Galaxies

AbstractWe present JHK observations of the metal-poor $$(\left[ {{\rm{Fe}}/{\rm{H}}} \right] < - 1.40)$$ dwarf-irregular galaxies, Leo A and Sextans A, obtained with the WIYN High-resolution Infrared Camera. Their near-IR stellar populations are characterized by using a combination of color-magnitude diagrams and by identifying long-period variable (LPV) stars. We detected red giant and asymptotic giant branch (AGB) stars, consistent with membership of the galaxy’s intermediate-age populations (2-8 Gyr old). We identify 32 dusty evolved stars in Leo A and 101 dusty stars in Sextans A, confirming that metal-poor stars can form substantial amounts of dust. We also find tentative evidence for oxygen-rich dust formation at low metallicity, contradicting previous models that suggest oxygen-rich dust production is inhibited in metal-poor environments. The majority of this dust is produced by a few very dusty evolved stars.

scholarly journals Speckle interferometry in the near-infrared

1979 ◽  
Vol 187 (3) ◽  
pp. 553-566 ◽  
Author(s):  
M. J. Selby ◽  
R. Wade ◽  
C. Sanchez Magro
Keyword(s):  
Near Infrared ◽  
Speckle Interferometry

scholarly journals High Angular Resolution Observations of Her 36

1994 ◽  
Vol 158 ◽  
pp. 364-366
Author(s):  
B. Stecklum ◽  
R.R. Howell ◽  
A. Eckart ◽  
A. Richichi
Keyword(s):  
Near Infrared ◽  
Angular Resolution ◽  
Speckle Interferometry ◽  
High Angular Resolution ◽  
Speckle Image ◽  
Lunar Occultation ◽  
L Band ◽  
Occultation Data

The star Herschel 36 (Her 36) which ionizes most of the Hourglass nebula has been observed during a lunar occultation as well as by speckle interferometry in the near infrared (NIR). From the lunar occultation data the strip brightness profile has been extracted which shows that in the L′ band Her 36 is extended with a FWHM of 0.45″. Subsequent speckle interferometry revealed 11 sources in a 6′ × 6′ area at a level of 0.15″ resolution. From the comparison of the brightness profile obtained by the occultation and the strip brightness profile synthesized from the speckle image, we conclude that Her 36 is surrounded by a very young infrared cluster.

scholarly journals Infrared Speckle Methods

1984 ◽  
Vol 79 ◽  
pp. 309-336 ◽  
Author(s):  
A. Chelli
Keyword(s):  
Optical Properties ◽  
Image Reconstruction ◽  
Spatial Resolution ◽  
Near Infrared ◽  
Speckle Interferometry ◽  
Reconstruction Methods ◽  
Interferometry Method ◽  
Large Telescopes

I-INTRODUCTION The speckle interferometry method has been introduced in 1970 by A. Labeyrie who showed in the visible dcmain that it was possible to reach the limiting spatial resolution of large telescopes. From 1977, the method is extended to the near infrared between 2 and 5ym (Lena, 1977; Wade and Selby, 1978) ,7 years later infrared speckle systems are operating on several large telescopes (ESO, KPNO, AAT, UKIRT, CFHT... ).The speckle interferometry method has allowed to better understanding the optical properties of the atmosphere, especially owing to the work of F.Roddier (Roddier, 1981). It has raised new problems like the phase restitution of the object spectrum and has largely contributed to the development of image reconstruction methods.

scholarly journals Detection and Photometry of Red Giants in the Magellanic Clouds

1984 ◽  
Vol 108 ◽  
pp. 183-194
Author(s):  
Marc Aaronson
Keyword(s):  
Stellar Population ◽  
Near Infrared ◽  
Formation Rate ◽  
Magellanic Clouds ◽  
Red Giants ◽  
Chemical Enrichment ◽  
Evolved Stars ◽  
Photometric Observations ◽  
Infrared Measurements ◽  
History Of

This review will focus on photometric observations of evolved stars in the Magellanic Clouds. Emphasis is placed on red and near-infrared measurements, as these allow reasonable estimates to be made of bolometric magnitude and temperature for reliable placement in the physical HR diagram. The review is divided into three parts: field stars, cluster stars, and red variables; a summary of the surveys for objects in each of these areas is also given. Particular attention is drawn to the intermediate-age stellar population, as this component appears to be the primary tracer of the star formation rate and chemical enrichment history of the Clouds.

scholarly journals Speckle Interferometry

1989 ◽  
Vol 8 ◽  
pp. 561-562
Author(s):  
J.C. Christou
Keyword(s):  
Near Infrared ◽  
High Spatial Frequency ◽  
Speckle Interferometry ◽  
Short Exposure ◽  
Limited Information ◽  
Interferometric Imaging ◽  
Current State ◽  
Pixel Detectors ◽  
Array Detectors ◽  
Optical Astronomy

Speckle interferometry is a technique which utilizes the full diffraction-limited imaging potential of ground-based telescopes. Short exposure images, or specklegrams, with an exposure time less than that of the atmospheric correlation time (~5- 50 ms) preserve the high-spatial frequency information lost in long exposure imaging. In 1970, Labeyrie computed the power spectrum of a set of specklegrams and showed that they contained diffraction-limited information. Since then the field has grown with improvements in both instrumentation and the phase recovery algorithms necessary for imaging. It has been applied at both visible and near-infrared wavelengths although, until recently, the latter has used slit-scanning techniques with single pixel detectors because of the lack of array detectors. The current state of speckle interferometry has been well covered in the proceedings of two recent joint National Optical Astronomy Observatories – European Southern Observatory workshops on Interferometric Imaging in Astronomy (Oracle, 1987 & Garching, 1988).

10 micron speckle interferometry observations of evolved stars

1989 ◽  
Vol 97 ◽  
pp. 1763 ◽  
Author(s):  
J. A. Benson ◽  
N. H. Turner ◽  
H. M. Dyck
Keyword(s):  
Speckle Interferometry ◽  
Evolved Stars
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