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天文館

臺北天文館學報(出版品)

臺北天文館學報 第5期(English)

JTAM VOL. 5 (2007)


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FieldAuthorTitleReceived DateAccepted Date
Solar SystemSun KwokExtraterrestrial Influence on the Evolution of the Early Earth(pdf檔案)Invited Articles--
Milky Way Infrared Ting-Hung Peng,
Chung-Ming Ko
A Study on the Galactic Structure by 2MASS(pdf檔案)2007.10.302007.11.29
Binary AstrometryInstrumentationHsieh-Hai Fu,
Yi-Cheng Yen
Speckle interferometry of selected binaries using webcam CCD(pdf檔案)2007.11.052007.12.07
----Abstracts of CAST Symposium 2007(pdf檔案)----

Title: Extraterrestrial Influence on the Evolution of the Early Earth

Author: Sun Kwok

Keywords:--

Abstract:
   After the formation of the solid Earth through accretion 4.6 billion years ago, the atmosphere and oceans of Earth have undergone significant alterations as the result of impacts by comets and asteroids during the heavy bombardment period. Isotopic and chemical analysis of meteorites, interplanetary dust particles, and even comets have now indicated a strong stellar-solar system connection and there is evidence that stellar-synthesized inorganic and organic compounds have been delivered to the solar system.

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Title: A Study on the Galactic Structure by 2MASS

Author: Ting-Hung Peng, Chung-Ming Ko

Keywords: Luminostiy Funcition, 2MASS, Star Counts, Galactic Structure

Abstract:
   Star count is one of the basic methods to study the structure of our Galaxy. The Two Micron All Sky Survey (2MASS) offers a better view of the global distribution of stars in our Galaxy than optical survey, because the extinction of near infrared is only 10% of that in the visible. We analyze the data of 2MASS Point Source Catalog for the whole sky at one degree resolution by differential star count. Except in the vicinity of the Galactic Center, the star count-apparent magnitude relation is well approximated by a single power law in the magnitude between 9 to 15, and the power law indices are roughly the same (~0.3) in the whole sky. The average power law indices of the whole sky in J, H, KS bands are 0.310±0.028, 0.311±0.024, 0.327±0.026, respectively.
   We fit the data by a simple double exponential disk for the Galaxy density distri- bution with a single power law luminosity function (LF). We neglect extinction in the fitting process. We consider main sequence stars from O3 type to M4 type only. The power law indices of LF in the galactic plane in the J, H, KS bands are 1.83, 1.8, 1.79, respectively. We adopt the least square method to find the parameters of number density profile of the Galaxy. The scale height, scale length, number density near the Sun and the position of the Sun above the mid-plane are about 400pc, 2.35 kpc, 0.06 pc -3, 28 pc respectively.

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Title: Speckle interferometry of selected binaries using webcam CCD

Author: Hsieh-Hai Fu, Yi-Cheng Yen

Keywords: binary, speckle, Castor

Abstract:
   There were 14 binaries chosen for speckle interferometry technique with a modified Philip 840K webcam CCD equipped on LOT, and 13 of them with component brighter than magnitude 6.5 are resolved in the range of angular separation 0.3" to 5.3". The scale, 0.043"/pixel, and position angle are calibrated in term of the bright binaries, Castor. According to this work, the commercial webcam CCD is suitable for speckle interferometry observation of binary to reach the diffraction limit of the small or moderate sized telescopes.

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Title: Abstracts of CAST Symposium 2007

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