A Study of the Energy Sources of Herbig—Haro Objects     

Jing－Wen  Yue－FangWu 《中国天文和天体物理学报》2002,2(1):33-42

1 INTRODUCTIONHerbig-Haro objects are a kind of semi-sta]c, semi-nebuIa objects associated with star fOrm-ing regions. Although such objects were noticed by Burnham as early as l890s, they did notattract much attention until the late 1940s until their independent rediscovery by Herbig andHaro in NGC 1999. A few years later, these objects were named Herbig-Haro objects fOr thefirst time by Ambartsumian (Reipurth 1997). In the fOllowing half century, the observationand theoretical res…  相似文献   

Erratum: Observations of flat-spectrum radio sources at λ850 μm from the James Clerk Maxwell Telescope – I. 1997 April to 2000 April     

E. I. Robson  J. A. Stevens  T. Jenness 《Monthly notices of the Royal Astronomical Society》2003,343(4):1376-1376

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Anatomy of the Herbig–Haro object HH7 bow shock     

Michael D. Smith  Tigran Khanzadyan  Christopher J. Davis 《Monthly notices of the Royal Astronomical Society》2003,339(2):524-536

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基于OCCI的空间数据库几何对象实现方法   总被引：1，自引：1，他引：0  

吴杰 陆锋汤井田  程昌秀袁正午 《地球信息科学学报》2003,5(4):16-21

海量空间数据的高效访问和操作是 GIS平台和应用系统开发的核心技术。本文分析了 Oracle数据库管理系统所提供的访问接口 OCI、OCCI及对象类型转换工具 OTT的特性 ,基于 OCCI和 OTT技术提出了一种面向对象的访问及操作 SDO几何对象的方法 ,并通过实例讨论了实现过程。该方法利用 SDO几何模型作为 Oracle服务端的几何对象载体 ,在客户端通过继承 SDO几何对象实现自定义几何对象模型 ,避免了 SDO几何对象与用户定义几何对象之间的空间数据转换过程 ,有利于扩展自定义空间数据模型。同时 ,自定义几何对象可以充分利用Oracle Spatial提供的空间操作与整合功能 ,加速 GIS软件平台研发过程。  相似文献   

矩尺天区的近红外天体     

肖真  李竞 《中国天文和天体物理学报》1994,(2)

利用Ｒ（红）－Ｉ（近红外）两色照相测光方法，搜寻银道带天区的红外超天体，并证认ＩＲＡＳ点源的红外超对应体。本文是一组系列文章的第四篇。在矩尺天区发现了１９５个红外超天体，并证认出其中２２个是ＩＲＡＳ点源的对应体。  相似文献   

Current problems in star formation and infrared surveys     

I. Appenzeller 《Astrophysics and Space Science》1994,217(1-2):201-206

Star forming regions and young stellar objects are well known to be strong sources of infrared radiation. Such objects will be among the conspicous targets in the upcoming NIR surveys. Therefore, these surveys promise important new information on various unsolved questions concerning the star formation process. Among the problems where significant progress can be expected are the environmental effects on star formation, the derivation of star formation efficiencies and star formation rates, and all questions related to the fragmentation process and the initial mass function. Moreover, the NIR surveys may also help identifying new examples of protostars and PMS objects for follow-up investigations of their physical structure.  相似文献   

Proper motion measurements in the HH 46/47 outflow     

Jochen Eislöffel 《Astrophysics and Space Science》1994,216(1-2):135-136

Proper motion measurements have been carried out for the HH 46/47 outflow system. The results of these measurements and some implications for the physics of the outflow and its modelling are discussed.  相似文献   

A symplectic mapping model for the 3/4 exterior     

kotoulas  Thomas A.  Hadjidemetriou  John D. 《Earth, Moon, and Planets》2003,93(3):203-232

We present a symplectic mapping model to study the evolution of a small body at the 3/4 exterior resonance with Neptune, for planar and for three dimensional motion. The mapping is based on the averaged Hamiltonian close to this resonance and is constructed in such a way that the topology of its phase space is similar to that of the Poincaré map of the elliptic restricted three-body problem. Using this model we study the evolution of a small object near the 3/4 resonance. Both chaotic and regular motions are found, and it is shown that the initial phase of the object plays an important role on the appearance of chaos. In the planar case, objects that are phase-protected from close encounters with Neptune have regular orbits even at eccentricities up to 0.44. On the other hand objects that are not phase protected show chaotic behaviour even at low eccentricities. The introduction of the inclination to our model affects the stable areas around the 3/4 mean motion resonance, which now become thinner and thinner and finally at is=10° the whole resonant region becomes chaotic. This may justify the absence of a large population of objects at this resonance.  相似文献   

The masses of central supermassive black holes and the variability time-scales in gamma-ray loud blazars     

E. W. Liang  H. T. Liu 《Monthly notices of the Royal Astronomical Society》2003,340(2):632-638

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Atlas of the mean motion resonances in the Solar System     

Tabaré Gallardo 《Icarus》2006,184(1):29-38

The aim of this work is to present a systematic survey of the strength of the mean motion resonances (MMRs) in the Solar System. We know by applying simple formulas where the resonances with the planets are located but there is no indication of the strength that these resonances have. We propose a numerical method for the calculation of this strength and we present an atlas of the MMRs constructed with this method. We found there exist several resonances unexpectedly strong and we look and find in the small bodies population several bodies captured in these resonances. In particular in the inner Solar System we find one asteroid in the resonance 6:5 with Venus, five asteroids in resonance 1:2 with Venus, three asteroids in resonance 1:2 with Earth and six asteroids in resonance 2:5 with Earth. We find some new possible co-orbitals of Earth, Mars, Saturn, Uranus and Neptune. We also present a discussion about the behavior of the resonant disturbing function and where the stable equilibrium points can be found at low and high inclination resonant orbits.  相似文献