scholarly journals Forty Years of Progress in Long-Baseline Optical Interferometry: 2005 Robert Ellery Lecture

2006 ◽  
Vol 23 (2) ◽  
pp. 94-104 ◽  
Author(s):  
John Davis
Keyword(s):  
Optical Interferometry ◽  
Black Belt ◽  
Single Star ◽  
Leading Role ◽  
Long Baseline ◽  
Stellar Interferometer ◽  
Observational Technique ◽  
Made In ◽  
Scientific Achievements ◽  
Personal Viewpoint

AbstractThe development of long-baseline optical interferometry in Australia from the Narrabri Stellar Intensity Interferometer (NSII) to the Sydney University Stellar Interferometer (SUSI) and the resulting technical and scientific achievements are described. Three examples of results from the SUSI programme, for a single star, a double-lined spectroscopic binary, and a Cepheid variable, are presented to illustrate the advances made in the past four decades. The leading role that Australia has played in the development of the field worldwide is discussed from a personal viewpoint. Long-baseline optical interferometry has promised much, has been slow to deliver, and has been restricted to black-belt interferometrists, but it has now matured to the point where it is becoming an observational technique for astronomers in general.

scholarly journals The Potential of Long–Baseline Optical Interferometry of Binary Stars

1992 ◽  
Vol 135 ◽  
pp. 527-535 ◽  
Author(s):  
H.A. McAlister
Keyword(s):  
Binary Stars ◽  
Speckle Interferometry ◽  
Stellar Mass ◽  
Optical Interferometry ◽  
Spectroscopic Binaries ◽  
Direct Imaging ◽  
Multiple Star ◽  
Long Baseline ◽  
Stellar Interferometer

AbstractInterferometric arrays possessing sub-milliarcsecond resolution are either about to be fully scientifically productive, as in the case of the Sydney University Stellar Interferometer, or are under various stages of planning and development. The 1990’s will thus witness a hundred–fold gain in resolution over speckle interferometry at the largest telescopes and 5,000 times the resolution of classical direct imaging. Where speckle interferometry can now resolve binary stars with periods of 1 to 2 years, interferometric arrays with baselines of hundreds of meters will resolve binaries with periods of a few hours. Arrays will resolve the majority of the known spectroscopic binaries, providing a substantial increase in the quantity and quality of stellar mass determinations. Surveys for new binaries among the field stars and other restricted samples will be accomplished with unprecedented completeness. The remarkable enhancement in resolution we are about to witness from facilities like SUSI and our own proposed CHARA Array will quite literally revolutionize the field of double and multiple star research.

Soil and ecological division into districts of the Baikal region

2018 ◽  
Vol 940 (10) ◽  
pp. 54-64 ◽  
Author(s):  
I.A. Belozertseva ◽  
A.A. Sorokovoj
Keyword(s):  
Baikal Region ◽  
Soil Cover ◽  
Soil Formation ◽  
Forest Steppe ◽  
Leading Role ◽  
Soil Cover Structure ◽  
Reflecting Surface ◽  
Heat And Moisture ◽  
Made In

On the basis of long-term researches of soils in the territory of Russia and Mongolia soil and ecological division into districts of the Baikal region is carried out. At division into districts the whole set of an environment of soil formation was considered. On the map of soil and ecological division into districts 13 mountain, mid-mountain, low-mountain taiga, foothill, hollow-valley, forest-steppe and steppe provinces reflecting surface device originality as the ratio of balance of heat and moisture forming a basis to zoning is shown against the background of difficult orography are allocated. In total 42 districts on lithologic-geomorphological features are allocated. In formation of distinctions of a soil cover of these provinces the leading role is played by bioclimatic factors and inside them the lithologic-geomorphological ones. In the view of structural approach of the district they are considered as territories with a certain natural change of several types of the soil cover structure caused by features of a relief and the parent rock. The map is made in the MapInfo program. It is revealed that on ill-defined width zoning of soils the vertical one which has a greater influence on soils of this region is imposed. Soils of the Baikal region are not similar to the soils located at the same latitude of the flat European territory of Russia. Zone soils of this territory are specific and original.

scholarly journals Reaching micro-arcsecond astrometry with long baseline optical interferometry

2014 ◽  
Vol 567 ◽  
pp. A75 ◽  
Author(s):  
S. Lacour ◽  
F. Eisenhauer ◽  
S. Gillessen ◽  
O. Pfuhl ◽  
J. Woillez ◽  
...  
Keyword(s):  
Optical Interferometry ◽  
Long Baseline

scholarly journals Interferometric studies of rapid rotators

2010 ◽  
Vol 6 (S272) ◽  
pp. 44-55 ◽  
Author(s):  
Ming Zhao ◽  
John D. Monnier ◽  
Xiao Che
Keyword(s):  
Fundamental Property ◽  
Optical Interferometry ◽  
Rotating Stars ◽  
Stellar Rotation ◽  
Rapid Rotation ◽  
Long Baseline ◽  
Imaging Results ◽  
Basic Physics ◽  
Stellar Photosphere

AbstractStellar rotation, like stellar mass and metallicity, is a fundamental property of stars. Rapid rotation distorts the stellar photosphere and affects a star's luminosity, abundances and evolution. It is also linked to stellar wind and mass loss. The distortion of the stellar photosphere due to rapid rotation causes the stellar surface brightness and effective temperature to vary with latitude, leading to a bright pole and a dark equator - a phenomenon known as ‘Gravity Darkening’. Thanks to the development of long baseline optical interferometry in recent years, optical interferometers have resolved the elongation of rapidly rotating stars, and have even imaged a few systems for the first time, directly confirming the gravity darkening effect. In this paper, we review the recent interferometric studies of rapid rotators, particularly the imaging results from CHARA-MIRC. These sub-milliarcsecond resolution observations permit the determination of the inclination, the polar and equatorial radius and temperature, as well as the fractional rotation speed of several rapid rotators with unprecedented precision. The modeling also allows the determination of the true effective temperatures and luminosities of these stars, permitting the investigation of their true locations on the HR diagram. Discrepancies from standard models were also found in some measurements, suggesting the requirement of more sophisticated mechanisms such as non-uniform rotation in the model. These observations have demonstrated that optical interferometry is now sufficiently mature to provide valuable constraints and even model-independent images to shed light on the basic physics of stars.

scholarly journals Long Baseline Interferometry and Binary Stars

1983 ◽  
Vol 62 ◽  
pp. 191-201
Author(s):  
John Davis
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Current Status ◽  
Fundamental Properties ◽  
Long Baseline ◽  
Stellar Interferometer ◽  
Spectroscopic Binary ◽  
Future Plans ◽  
Intensity Interferometer

AbstractThe observations of α Vir with the Narrabri Stellar Intensity Interferometer demonstrated the potential of long baseline interferometry for the determination of fundamental properties of double-lined spectroscopic binary systems. Since the completion of the programme with the Narrabri instrument the Chatterton Astronomy Department has been conducting a study aimed at developing a stellar interferometer with limiting magnitude V ≳ +8 and maximum baseline ≳ 1 km (resolution at 500 nm ≲ 7 × 10−5 seconds of arc). The way in which a long baseline interferometer may be used in the study of binary stars is outlined, the requirements for this work are discussed, and the current status and future plans of the Chatterton Astronomy Department’s programme to develop a new long baseline interferometer are summarised.

scholarly journals Long Baseline Optical Interferometry

1989 ◽  
Vol 8 ◽  
pp. 559-560
Author(s):  
S.T. Ridgway
Keyword(s):  
Emission Line ◽  
Spatial Resolution ◽  
Optical Interferometry ◽  
Hydrogen Emission ◽  
Long Baseline ◽  
Optical Interferometers ◽  
Imaging Science ◽  
Be Star ◽  
Hydrogen Emission Line ◽  
To Come

During the last three years significant results have been obtained from several operational, long baseline optical interferometers. Precision stellar angular diameters (accuracy of order 2% and better) have been reported in the infrared (DiBenedetto and Rabbia, 1987) and in the visible (Davis and Tango, 1986). Astrometric precision of order 20 milliarcsec has been demonstrated over large angles (Shao et al, in press). Spectro-spatial resolution of the disk of a Be star in the hydrogen emission line (Thom et al., 1986) suggests spectacular imaging science to come with many-telescope coherent and phased optical arrays.

The Giangiacomo Feltrinelli Institute

1972 ◽  
Vol 2 ◽  
pp. 19-21
Author(s):  
Victoria de Grazia
Keyword(s):  
Working Class ◽  
Economic Thought ◽  
The Political ◽  
Postwar Period ◽  
Intellectual Life ◽  
Political Debate ◽  
Leading Role ◽  
Research Activities ◽  
The Social ◽  
Made In

The Feltrinelli Institute was founded in 1949 by the Milanese publisher Giangiacomo Feltrinelli – its aim “to promote the knowledge and study – carried out in accordance with strictly scientific criteria and complete ideological autonomy – of the history, the political and economic thought and the social ideas of the modern and contemporary eras; particular importance is to be given to Italy and to the economic phenomena, political doctrines and more historically important social movements of the country.” Feltrinelli's initiative, which began with the library and a rich collection of materials on French socialism, was an important first step toward filling the vacuum in documentation and research on the Italian working class and socialist movements left by two decades of Fascist government. In the following years, the library and research activities of the Institute played a leading role in the reconstruction of intellectual life and political debate in Italy. Its publications, especially Movimento Operaio (1947–1955) and the Annali (1958-) contained some of the most important contributions to the study of the Italian working class and peasantry, and socialist movements made in the postwar period.

scholarly journals Sub-Milliarcsecond Optical Astrometry and Binary Stars

1995 ◽  
Vol 166 ◽  
pp. 193-202
Author(s):  
J.T. Armstrong
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Optical Interferometry ◽  
Light Curves ◽  
Spectroscopic Binaries ◽  
Indirect Methods ◽  
Fundamental Parameters ◽  
Long Baseline

Long-baseline optical interferometry has made it possible to measure the visual orbits of binary stars with major axes as small as 5 mas and errors of ≲ 100 μas. Interferometers now nearing completion will extend these values to ≳ 500 μas and σa ∼ 10 μas. Observations of double-lined spectroscopic binaries with current interferometers have already yielded some mass estimates with precisions rivaling those from fitting the light curves of eclipsing double-lined systems. Luminosity estimates based on combined visual interferometric observations and velocity curves are often more precise than those from more indirect methods based on estimates of Teff. New interferometers now coming into operation will make it possible to measure fundamental parameters in dozens to hundreds of binary systems.

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