共查询到20条相似文献,搜索用时 15 毫秒
1.
Jun-Liang Zhao Li Chen Wen Wen Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai Shanghai University Shanghai 《中国天文和天体物理学报》2006,6(4):435-446
From photographic plate data of Shanghai Astronomical Observatory with a time baseline of 87 years, proper motions and membership probabilities of 364 stars in the open cluster NGC 6530 region are reduced. On the basis of membership determination, luminosity function and segregation effect of the cluster are discussed with details. Spatial mass segregation is obviously present in NGC 6530 while there is no clear evidence for a velocity-mass (or velocity-luminosity) dependence. The observed spatial mass segregation for NGC 6530 might be due to a combination of initial conditions and relaxation process. 相似文献
2.
Zhen-Yu Wu Jia-Ji Wang Li ChenShanghai Astronomical Observatory Chinese Academy of Sciences Shanghai National Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2002,2(3):216-225
We examine 14 plates of the globular cluster M3 (NGC 5272) taken with the 40 cm refractor at the Sheshan station of Shanghai Astronomical Observatory. The plates span over a period of about 77 years. The positions and absolute proper motions of eight stars in the Hipparcos Catalogue and of 49 stars in the Tycho-2 Catalogue are used as the reference frame. The astrometric reduction is made with the central overlapping principle. The absolute proper motions of 534 stars in a region of about 100' × 100' around the cluster are measured. With the new proper motion data the membership probabilities of the stars are determined. The average absolute proper motion obtained for the cluster is -0.06@0.30 mas yr-1 in R.A. and -2.6@0.30 mas yr-1 in Decl. By combining this result with the known distance and radial velocity of the cluster, we also obtained the Galactic orbit of M3 for a chosen three-component Galactic potential. 相似文献
3.
《Chinese Astronomy and Astrophysics》2006,30(3):274-283
or stars in the region around the open cluster NGC6530, cluster memberships are calculated based on the maximum likelihood principle using proper motions obtained from photographic plates acquired with the 40 cm refraction telescope at Shanghai Astronomical Observatory. Analyses show that the membership determination is very effective with 250 stars having membership probabilities p ≥ 0.9. The spatial motion of the star cluster is also determined and a simple discussion is carried out. 相似文献
4.
The hydrogen Balmer‐α emission line spectrum of ten diffuse ionization sources in the Milk Way – NGC 40 (WC8), NGC 2022, NGC 6210, NGC 6618 (M17, Sh2‐45), NGC 6720 (M57), NGC 6781, NGC 6888 (Sh2‐105), NGC 6992 (Sh2‐103), NGC 7635 (Sh2‐162,) and IC 1848 (Sh2‐199) – has been investigated using a dual etalon Fabry‐Pérot optical spectrometer (DEFPOS) aatached to the 150 cm RTT150 telescope at TUBITAK National Observatory (TUG, Antalya, Turkey: 36° 51′ N; 30° 20′ E; elevation: 2547 m). All of our galactic Hα observations discussed in this paper were carried out during the nights of 2013 June 21–24 with exposure time of 3600 s. As main results the intensity, the full width at half maximum, and the radial velocity with respect to the LSR have been determined for each data set. The intensities, the radial velocities, and the line widths of the Hα emission line vary from 59.15 to 8923.44 R, –46.72 to +54.07 km s–1, and 31.4 to 48.01 km s–1, respectively. The radial velocities and the half‐widths of the Hii regions and planetary nebulae determined from our measurements are found tobe consistent with values given in literature, especially with those in Schneider et al. (1983) and Fich et al. (1990). (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
5.
We present a CCD BV photometry of the possible binary open star cluster NGC 7031/NGC 7086. The aim is to confirm or disprove their common nature on the grounds of their age and distance. An age of 224 ± 25 Myr and a distance of 831 ± 72 pc was determined for NGC 7031, and 178 ± 25 Myr, 955 ± 84 pc for NGC 7086, respectively. Based on these differences in age and distance we conclude that the two clusters are most likely not formed together from one and the same giant molecular cloud and thus do not form a true binary cluster. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
6.
Rebecca A. W. Elson Steinn Sigurdsson Melvyn Davies Jarrod Hurley & Gerard Gilmore 《Monthly notices of the Royal Astronomical Society》1998,300(3):857-862
We determine the binary star fraction as a function of radius in NGC 1818, a young rich cluster in the Large Magellanic Cloud, using Hubble Space Telescope images in bands F336W (∼ U ) and F555W (∼ V ). Our sample includes binaries with M primary ∼ 2–5.5 M⊙ and M secondary ≳ 0.7 Mprimary . The binary fraction increases towards the cluster centre, from ∼ 20 ± 5 per cent in the outer parts, to ∼ 35 ± 5 per cent inside the core. This increase is consistent with dynamical mass segregation and need not be primordial. We compare our results with expectations from N -body models, and discuss the implications for the formation and early evolution of such clusters. 相似文献
7.
136 stars which were known to be members of the open cluster NGC 752 were observed at the R band with the ROTSE–IIId telescope located at the Turkish National Observatory (TUG) site. The data had been evaluated together with BV and 2MASS photometric data. A new practical method for separating dwarf and giant was described and applied. Evaluating the colour magnitude–diagrams with Padova isochrones revealed for the open cluster NGC 752 a metallicity similar to the Sun and an age of 1.41 ± 0.20 Gyr. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
8.
M.M. Hohle T. Eisenbeiss M. Mugrauer F. Freistetter M. Moualla R. Neuhuser St. Raetz T.O.B. Schmidt N. Tetzlaff M. Vako 《Astronomische Nachrichten》2009,330(5):511-517
In this work we present detailed photometric results of the trapezium like galactic nearby OB clusters NGC 1502 and NGC 2169 carried out at the University Observatory Jena. We determined absolute BVRI magnitudes of the mostly resolved components using Landolt standard stars. This multi colour photometry enables us to estimate spectral type and absorption as well as the masses of the components, which were not available for most of the cluster members in the literature so far, using models of stellar evolution. Furthermore, we investigated the optical spectrum of the components ADS 2984A and SZ Cam of the sextuple system in NGC 1502. Our spectra clearly confirm the multiplicity of these components, which is the first investigation of this kind at the University Observatory Jena (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
9.
PMAS, the Potsdam Multi‐Aperture Spectrophotometer, is a new integral field instrument which was commissioned at the Calar Alto 3.5 m Telescope in May 2001. We report on results obtained from a science verification run in October 2001. We present observations of the low‐metallicity blue compact dwarf galaxy SBS0335‐052, the ultra‐luminous X‐ray Source X‐1 in the Holmberg II galaxy, the quadruple gravitational lens system Q2237+0305 (the “Einstein Cross”), the Galactic planetary nebula NGC7027, and extragalactic planetary nebulae in M31. PMAS is now available as a common user instrument at Calar Alto Observatory. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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11.
J.‐L. Prieur M. Scardia L. Pansecchi R.W. Argyle A. Zanutta E. Aristidi 《Astronomische Nachrichten》2014,335(8):817-832
We present relative astrometric measurements of visual binaries, made in 2012 with the speckle camera PISCO at the 102‐cm Zeiss telescope of Brera Astronomical Observatory, in Merate. Our observing list contains orbital couples as well as binaries whose motion is still uncertain. We obtained 355 new measurements of 344 visual binary stars, with angular separations in the range 0′.14–6′.9, and an average accuracy of 0.′02. The mean error on the position angles is 0°.5. Most of the position angles were determined without the usual 180° ambiguity with the application of triple‐correlation techniques and/or by inspection of the long integration files. We also present new revised orbits for ADS 10786 BC, 12144, 12515, 16314, and 16539, partly derived from PISCO observations. The corresponding estimated values for the masses of those systems are compatible with the spectral types. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
12.
M. Scardia J.‐L. Prieur L. Pansecchi R. W. Argyle A. Zanutta E. Aristidi 《Astronomische Nachrichten》2015,336(4):388-400
We present relative astrometric measurements of visual binaries made in 2013 with the speckle camera PISCO at the 102‐cm Zeiss telescope of Brera Astronomical Observatory, in Merate. Our observing list contains orbital couples as well as binaries whose motion is still uncertain. We obtained 134 new measurements of 129 visual binary stars, with angular separations in the range 0.≈23–5 and an average accuracy of 0.≈01. The mean error on the position angles is 0.°5. Most of the position angles were determined without the usual 180° ambiguity with the application of triple‐correlation techniques and/or by inspection of the long integration files. We also present new revised orbits for ADS 1097, 5871, 7203, 7775, 9378, 9578, and 11186, partly derived from PISCO observations. The corresponding estimated values for the masses of those systems are compatible with the spectral types. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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14.
K. A. Stoyanov R. K. Zamanov G. Y. Latev A. Y. Abedin N. A. Tomov 《Astronomische Nachrichten》2014,335(10):1060-1063
We present new radial velocities of the high‐mass X‐ray binary star 4U 2206+54 based on optical spectra obtained with the Coudé spectrograph at the 2 m RCC telescope of the Rozhen National Astronomical Observatory, Bulgaria in the period November 2011–July 2013. The radial velocity curve of the He I δ6678 Å line is modeled with an orbital period Porb = 9.568 d and an eccentricity of e = 0.3. These new measurements of the radial velocity resolve the disagreements of the orbital period discussions. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
15.
T.P. Roberts M.R. Goad M.J. Ward R.S. Warwick P.T. O'Brien P. Lira A.D.P. Hands 《Monthly notices of the Royal Astronomical Society》2001,325(2):L7-L11
We report the identification of a possible optical counterpart to the super-Eddington X-ray source NGC 5204 X-1. New Chandra data show that the X-ray source is point-like, with a luminosity of 5.2×1039 erg s−1 (0.5–8 keV) . It displays medium- and long-term X-ray variability in observations spanning a period of 20 yr. The accurate Chandra position allows us to identify a blue optical continuum source ( m v =19.7) at the position of NGC 5204 X-1, using newly obtained optical data from the INTEGRAL instrument on the William Herschel Telescope. The X-ray and optical source properties are consistent with the scenario in which we are observing the beamed X-ray emission of a high-mass X-ray binary in NGC 5204, composed of an O star with either a black hole or neutron star companion. 相似文献
16.
S. Yu. Gorda Yu. Yu. Balega E. A. Pluzhnik Z. U. Shkhagosheva 《Astrophysical Bulletin》2007,62(4):352-359
A complete set of parameters of the apparent relative orbit of the third body in the SZ Cam system is determined for the first time based on new speckle-interferometric and photometric observations of the eclipsing binary SZ Cam made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences and 0.5-m telescope of the Astronomical Observatory of Ural State University and published data. The mass of the third body and the distance to SZ Cam are estimated at M 3 = 23.4M ⊙ and d = 1125 kpc, respectively. The binary nature of the third body is confirmed. It is suggested that SZ Cam is possibly not a member of the open star cluster NGC 1502 onto whose center it projects. A total of 16 new times of minima of SZ Cam are reported. 相似文献
17.
本文发表的是用北京天文台60厘米施密特望远镜进行发射线星系物端棱镜巡天结果的第四篇文章。文中的表1包括100个发射线天体,其中的96个是发射线星系;其余的对象有3个行星状星云,1个发射线星。在这些发射线星系中,属于s,sd型的有69个,d,ds型的有27个,分别占72%和28%。除了4个已知的Seyfert星系之外,至少还有5个也可能是Seyfert星系。这些发射线天体中的23个是IRAS源,它们都与具有强发射的现象相联系. 相似文献
18.
Martin Cohen Quentin A. Parker Anne J. Green 《Monthly notices of the Royal Astronomical Society》2005,360(4):1439-1447
In a search for new Galactic planetary nebulae from our systematic scans of the Anglo-Australian Observatory/United Kingdom Schmidt Telescope (AAO/UKST) Hα Survey of the Southern Galactic Plane, we have identified a Population I Wolf–Rayet star of type WN7h associated with an unusual ring nebula that has a fractured rim. We present imagery in Hα, the 843-MHz continuum from the Molonglo Observatory Synthesis Telescope (MOST), the mid-infrared from the Midcourse Space Experiment ( MSX ), and confirmatory optical spectroscopy of the character of the nebula and of its central star. The inner edge of the Hα shell shows gravitational instabilities with a well-defined wavelength around its complete circumference. 相似文献
19.
我们用北京天文台兴隆观测站60厘米望远镜对NGC1019等10个旋涡星系进行了CCD照相观测,通过对图象的预处理及利用彭秋和(1988年)提出的方法,得到了这10个星系盘的等值高度和星系的倾角(星系平面和天球切平面之间的夹角)等一些重要物理量. 相似文献
20.
We used the star counts in 21 BATC fields obtained with the National Astronomical Observatories (NAOC) 60/90 cm Schmidt Telescope to study the structure of the Galactic halo.Adopting a de Vaucouleurs γ/4 law halo,we found that the halo is somewhat flatter (c/a~0.4) towards the Galactic center than in the anticentre and antirotation direction (c/a > 0.4).We also notice that the axial ratios are smaller (flatter) towards the low latitude fields than the high latitude fields,except for a few fields.We provide robust limits on the large-scale flattening of the halo.Our analysis shows that the axial ratio of the halo may vary with distance and the observation direction.At large Galactocentric radii,the halo may not have a smooth density distribution,but rather,it may be largely composed of overlapping streams or substructures,which provides a support for the hybrid formation model. 相似文献