258 research outputs found
Report of IAU Commission 30 on Radial Velocities (2006-2009)
Brief summaries are given on the following subjects: Radial velocities and
exoplanets (Toward Earth-mass planets; Retired A stars and their planets;
Current status and prospects); Toward higher radial velocity precision; Radial
velocities and asteroseismology; Radial velocities in Galactic and
extragalactic clusters; Radial velocities for field giants; Galactic structure
-- Large surveys (The Geneva-Copenhagen Survey; Sloan Digital Sky Survey;
RAVE); Working groups (WG on radial velocity standards; WG on stellar radial
velocity bibliography; WG on the catalogue of orbital elements of spectroscopic
binaries [SB9]).Comment: 11 pages, to appear in the IAU Transactions Vol. XXVIIA, Reports on
Astronomy 2006-2009, ed. Karel van der Hucht. Editor: G. Torre
Chinese writing system: Forms and methods of memorizing
© Serials Publications. The relevance of the problem in question is caused by the necessity of developing the most effective method of studying of one of the most important and most complex aspects of Chinese: the writing system. This study is directed at examining the most efficient forms and methods of memorizing Chinese characters. In the process of our work we also analyzed and presented the main techniques of learning and methods of teaching Chinese characters created by Chinese and Russian scholars. The leading approach to this problem is the problem-thematic approach. The key findings of the study are in the systematization of the main mechanisms and principles of learning and memorizing Chinese characters. The materials of this article may be helpful for school and university teachers of Chinese at the earliest stages of the students' learning, as well as for educators and developers of educational materials
Automated search for star clusters in large multiband surveys: II. Discovery and investigation of open clusters in the Galactic plane
Automated search for star clusters in J,H,K_s data from 2MASS catalog has
been performed using the method developed by Koposov et. al (2008). We have
found and verified 153 new clusters in the interval of the galactic latitude
-24 < b < 24 degrees. Color excesses E(B-V), distance moduli and ages were
determined for 130 new and 14 yet-unstudied known clusters. In this paper, we
publish a catalog of coordinates, diameters, and main parameters of all the
clusters under study. A special web-site available at http://ocl.sai.msu.ru has
been developed to facilitate dissemination and scientific usage of the results.Comment: 9 pages, 3 tables, 5 figures, accepted to Astronomy Letter
Leading Wave as a Component of the Spiral Pattern of the Galaxy
The spiral pattern of the Galaxy identified by analyzing the kinematics of
young stars within 3 kpc of the Sun is Fourier decomposed into spiral
harmonics. The spiral pattern of the Galaxy is shown to be representable as a
superposition of trailing and leading waves with interarm distances of
1.8(+/-0.4) kpc and 4(+/-2) kpc, respectively. Shock waves are probably present
only in the portions of the trailing spiral pattern where it crosses the crest
of the leading wave. The small interarm distance of the trailing spiral wave
(1.8 kpc) can be explained by its evolution - by the decrease in the interarm
distance as the wave is displaced toward the inner Lindblad resonance. The
Carina arm may be part of this resonance ring.Comment: 17 pages, 4 figures, to be published in Astronomy Letters, 200
In Search of Possible Associations between Planetary Nebulae and Open Clusters
We consider the possibility of cluster membership for 13 planetary nebulae
that are located in close proximity to open clusters lying in their lines of
sight. The short lifetimes and low sample size of intermediate-mass planetary
nebulae with respect to nearby open clusters conspire to reduce the probability
of observing a true association. Not surprisingly, line of sight coincidences
almost certainly exist for 7 of the 13 cases considered. Additional studies are
advocated, however, for 6 planetary nebula/open cluster coincidences in which a
physical association is not excluded by the available evidence, namely M
1-80/Berkeley 57, NGC 2438/NGC 2437, NGC 2452/NGC 2453, VBRC 2 & NGC 2899/IC
2488, and HeFa 1/NGC 6067. A number of additional potential associations
between planetary nebulae and open clusters is tabulated for reference
purposes. It is noteworthy that the strongest cases involve planetary nebulae
lying in cluster coronae, a feature also found for short-period cluster
Cepheids, which are themselves potential progenitors of planetary nebulae.Comment: Accepted for publication in PASP (December 2007
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