J/A+A/522/A65 Lunar occultations at the ESO VLT (Richichi+, 2010)
New high-sensitivity, milliarcsecond resolution results from routine
observations of lunar occultations at the ESO VLT.
Richichi A., Fors O., Chen W.-P., Mason E.
<Astron. Astrophys., 522, A65-65 (2010)>
=2010A&A...522A..65R 2010A&A...522A..65R
ADC_Keywords: Infrared sources ; Stars, double and multiple
Keywords: techniques: high angular resolution - occultations -
binaries: general - stars: fundamental parameters -
circumstellar matter - infrared: stars
Abstract:
Lunar occultations (LO) are a very efficient and powerful technique
that achieves the best combination of high angular resolution and
sensitivity possible today at near-infrared wavelengths. Given that
the events are fixed in time, that the sources are occulted randomly,
and that the telescope use is minimal, the technique is very well
suited for service mode observations.
We have established a program of routine LO observations at the VLT
observatory, especially designed to take advantage of short breaks
available in-between other programs. We have used the ISAAC instrument
in burst mode, capable of producing continuous read-outs at
millisecond rates on a suitable subwindow. Given the random nature of
the source selection, our aim has been primarily the investigation of
a large number of stellar sources at the highest angular resolution in
order to detect new binaries. Serendipitous results such as resolved
sources and detection of circumstellar components were also
anticipated.
Description:
We have recorded the signal from background stars for a few seconds,
around the predicted time of occultation by the Moon's dark limb. At
millisecond time resolution, a characteristic diffraction pattern can
be observed. Patterns for two or more sources superimpose linearly,
and this property is used for the detection of binary stars. The
detailed analysis of the diffraction fringes can be used to measure
specific properties such as the stellar angular size and the presence
of extended light sources such as a circumstellar shell.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 85 191 List of the recorded occultation events
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See also:
VI/132 : Lunar Occultation Archive (Herald+ 2010)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/AJ/112/2786 : 1985-1995 lunar occultations at TIRGO (Richichi+ 1996)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2MASS 2MASS designation (HHMMSSss+DDMMSSs)
18- 27 A10 "DD/MM/YYYY" Occ.date UT Date of occultation
29- 36 A8 "h:m:s" Occ.time UT time of occultation
38- 42 F5.2 mag Jmag 2MASS J magnitude
44- 48 F5.2 mag Hmag 2MASS H magnitude
50- 54 F5.2 mag Kmag 2MASS Ks magnitude
56- 63 A8 --- SpType MK spectral type
65- 85 A21 --- OName Other name of the star
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 01-Mar-2011