Pub Date : 1997-08-18DOI: 10.1017/S1539299600020839
E. Standish
The latest JPL planetary and lunar ephemerides, DE405, are referenced to the International Celestial Reference Frame (ICRF) with an accuracy that approaches 1 mas for the four innermost planets, the sun, and the moon. This has been accomplished mainly by 18 VLBI observations of the Magellan Spacecraft in orbit around Venus. The ephemeris of Jupiter, however, is not well-determined since the various observations are not consistent within each other. The outer four planets continue to rely almost entirely upon optical observations; their ephemeris uncertainties lie in the 100-200 mas range.
{"title":"Linking the Dynamical Reference Frame to the ICRF","authors":"E. Standish","doi":"10.1017/S1539299600020839","DOIUrl":"https://doi.org/10.1017/S1539299600020839","url":null,"abstract":"The latest JPL planetary and lunar ephemerides, DE405, are referenced to the International Celestial Reference Frame (ICRF) with an accuracy that approaches 1 mas for the four innermost planets, the sun, and the moon. This has been accomplished mainly by 18 VLBI observations of the Magellan Spacecraft in orbit around Venus. The ephemeris of Jupiter, however, is not well-determined since the various observations are not consistent within each other. The outer four planets continue to rely almost entirely upon optical observations; their ephemeris uncertainties lie in the 100-200 mas range.","PeriodicalId":422890,"journal":{"name":"Highlights of Astronomy","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133013882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-08-01DOI: 10.1017/S1539299600022280
J. Holmberg, L. Lindegren, C. Flynn
We use the Hipparcos survey to derive an improved model of the local galactic structure. The availability of parallaxes for all the stars permits direct determination of stellar distributions, elim inating the basic indeterminacy of classical methods based on star counts. Hipparcos gives for the first time a truly three-dimensional view of the solar vicinity, and a complete, homogeneous and highly accurate set of magnitudes and colours. This means that new techniques can be applied in the treatment of the data which place strong constraints on a model that tries to describe the local Galactic structure. Here we investigate how well a static model of low complexity can describe the Hipparcos observations. The interpretation of the Hipparcos data is complicated by various observational errors and selection effects that are hard to treat correctly. We do not try to correct the data, but instead use a model and subject this model to the same observational errors and selection effects. A model catalogue is created that can be compared with the observed catalogue directly in the observational domain, thereby eliminating the effects from various biases. This and features the are well by the model the rather detailed modelling of the joint Mv/B distribution. separate distributions were derived for the three different components, disk, thick disk and halo, using the kinematic characteristics of the components to discriminate between them.
{"title":"Towards an Improved Model of the Galaxy","authors":"J. Holmberg, L. Lindegren, C. Flynn","doi":"10.1017/S1539299600022280","DOIUrl":"https://doi.org/10.1017/S1539299600022280","url":null,"abstract":"We use the Hipparcos survey to derive an improved model of the local galactic structure. The availability of parallaxes for all the stars permits direct determination of stellar distributions, elim inating the basic indeterminacy of classical methods based on star counts. Hipparcos gives for the first time a truly three-dimensional view of the solar vicinity, and a complete, homogeneous and highly accurate set of magnitudes and colours. This means that new techniques can be applied in the treatment of the data which place strong constraints on a model that tries to describe the local Galactic structure. Here we investigate how well a static model of low complexity can describe the Hipparcos observations. The interpretation of the Hipparcos data is complicated by various observational errors and selection effects that are hard to treat correctly. We do not try to correct the data, but instead use a model and subject this model to the same observational errors and selection effects. A model catalogue is created that can be compared with the observed catalogue directly in the observational domain, thereby eliminating the effects from various biases. This and features the are well by the model the rather detailed modelling of the joint Mv/B distribution. separate distributions were derived for the three different components, disk, thick disk and halo, using the kinematic characteristics of the components to discriminate between them.","PeriodicalId":422890,"journal":{"name":"Highlights of Astronomy","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130534919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-08-01DOI: 10.1017/S1539299600022383
T. Tsujimoto, M. Miyamoto, Y. Yoshii
The present determination of the absolute magnitude .M v (RR) of RR Lyrae stars is twofold, relying upon Hipparcos proper motions and trigonometric parallaxes separately. First, applying the statistical parallax method to the proper motions, we find v (RR)>= 0.69 ± 0.10 for 99 halo RR Lyraes with = -1.58. Second, applying the Lutz-Kelker correction to the RR Lyrae HIP95497 with the most accurately measured parallax, we obtain M v (RR) = 0.57-0.74 at [Fe/H]=-1.6. Furthermore, allowing full use of low accuracy and negative parallaxes as well for 125 RR Lyraes with - 2.49≤[Fe/H]≤0.07, the maximum likelihood estimation yields the relation, M v (RR)= (0.59±0.37)+(0.20±0.63)([Fe/H]+1.60), which formally agrees with the recent preferred relation. The same estimation yields again My (RR) = 0.65 ± 0.33 for the 99 halo RR Lyraes. Although the formal errors in the latter two estimates are rather large, all of the four results suggest the fainter absolute magnitude, My(RR)=0.6-0.7 at [Fe/H]=-1.6. The present results still provide the lower limit on the age of the universe which is inconsistent with a fiat, matter-dominated universe and current estimates of the Hubble constant.
目前对天琴座RR星的绝对星等m.v (RR)的测定是双重的，分别依靠依巴谷固有运动和三角视差。首先，将统计视差方法应用于固有运动，我们发现99晕RR Lyraes的v (RR)>= 0.69±0.10，= -1.58。其次，对视差测量精度最高的RR Lyrae HIP95497进行Lutz-Kelker校正，得到[Fe/H]=-1.6时的M v (RR) = 0.57-0.74。此外，在充分考虑低精度和负视差的情况下，对于- 2.49≤[Fe/H]≤0.07的125 RR Lyraes，最大似然估计得到的关系为M v (RR)=(0.59±0.37)+(0.20±0.63)([Fe/H]+1.60)，与最近的优选关系正式一致。同样的估计也得出了99晕天琴座RR的My (RR) = 0.65±0.33。虽然后两种估计的形式误差相当大，但所有四种结果都表明绝对星等较弱，在[Fe/H]=-1.6时，My(RR)=0.6-0.7。目前的结果仍然提供了宇宙年龄的下限，这与固定的、物质主导的宇宙和目前对哈勃常数的估计不一致。
{"title":"The Absolute Magnitude Of RR Lyrae Stars","authors":"T. Tsujimoto, M. Miyamoto, Y. Yoshii","doi":"10.1017/S1539299600022383","DOIUrl":"https://doi.org/10.1017/S1539299600022383","url":null,"abstract":"The present determination of the absolute magnitude .M v (RR) of RR Lyrae stars is twofold, relying upon Hipparcos proper motions and trigonometric parallaxes separately. First, applying the statistical parallax method to the proper motions, we find v (RR)>= 0.69 ± 0.10 for 99 halo RR Lyraes with = -1.58. Second, applying the Lutz-Kelker correction to the RR Lyrae HIP95497 with the most accurately measured parallax, we obtain M v (RR) = 0.57-0.74 at [Fe/H]=-1.6. Furthermore, allowing full use of low accuracy and negative parallaxes as well for 125 RR Lyraes with - 2.49≤[Fe/H]≤0.07, the maximum likelihood estimation yields the relation, M v (RR)= (0.59±0.37)+(0.20±0.63)([Fe/H]+1.60), which formally agrees with the recent preferred relation. The same estimation yields again My (RR) = 0.65 ± 0.33 for the 99 halo RR Lyraes. Although the formal errors in the latter two estimates are rather large, all of the four results suggest the fainter absolute magnitude, My(RR)=0.6-0.7 at [Fe/H]=-1.6. The present results still provide the lower limit on the age of the universe which is inconsistent with a fiat, matter-dominated universe and current estimates of the Hubble constant.","PeriodicalId":422890,"journal":{"name":"Highlights of Astronomy","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131364866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-08-01DOI: 10.1017/S1539299600022310
A. Gómez, S. Grenier, S. Udry, M. Haywood, V. Sabas, L. Meillon, F. Royer, Y. Lebreton
Using Hipparcos parallaxes and proper motions together with radial velocity complementary data (Coravel for late type stars and new ground-based data for early type stars) for several thousand B-F type stars, the velocity ellipsoid has been determined as a function of age. The variations with age of the ratio of the velocity dispersions, of the vertex deviation and the age-velocity dispersion relation (AVR) have been estimated. Our results connrm that mixing is not complete at about 0:8 ? 1 Gyr. The shape of the velocity ellipsoid changes with time, getting rounder from a maximum, thereafter remaining roughly constant; there is no dynamically signiicant evolution of the disk after about 4 ? 5 Gyr. The velocity dispersion in the direction perpendicular to the galactic plane saturates at about 15?17 km s ?1 for thin disk stars. The vertex deviation declines with age and remains near zero after 5 Gyr.
{"title":"Kinematics of Disk Stars in the Solar Neighbourhood","authors":"A. Gómez, S. Grenier, S. Udry, M. Haywood, V. Sabas, L. Meillon, F. Royer, Y. Lebreton","doi":"10.1017/S1539299600022310","DOIUrl":"https://doi.org/10.1017/S1539299600022310","url":null,"abstract":"Using Hipparcos parallaxes and proper motions together with radial velocity complementary data (Coravel for late type stars and new ground-based data for early type stars) for several thousand B-F type stars, the velocity ellipsoid has been determined as a function of age. The variations with age of the ratio of the velocity dispersions, of the vertex deviation and the age-velocity dispersion relation (AVR) have been estimated. Our results connrm that mixing is not complete at about 0:8 ? 1 Gyr. The shape of the velocity ellipsoid changes with time, getting rounder from a maximum, thereafter remaining roughly constant; there is no dynamically signiicant evolution of the disk after about 4 ? 5 Gyr. The velocity dispersion in the direction perpendicular to the galactic plane saturates at about 15?17 km s ?1 for thin disk stars. The vertex deviation declines with age and remains near zero after 5 Gyr.","PeriodicalId":422890,"journal":{"name":"Highlights of Astronomy","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116597764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-07-01DOI: 10.1017/S1539299600019912
Robert E. Williams
Great progress has been made in recent years in understanding the large-scale structure of the universe. Recall that it is only within this century that we have even come to realize the existence of other galaxies as separate entities. Until the 1920’s the universe did not extend beyond the Milky Way. Novae and Cepheid variables changed that picture, and for the past 75 years extragalactic astronomy has been one of the most active and fertile areas of science. The concept of an expanding universe and its beginning in a Big Bang all derive from the discovery of external galaxies. Distant galaxies are faint and have small angular sizes, therefore their study has remained the province of the largest telescopes. Before the launch of Hubble Space Telescope, ground-based telescopes had succeeded in detecting distant galaxies out to redshifts of z ~ 1, and in establishing certain of their characteristics. But, there was uncertainty as to how much further HST could push the study of distant galaxies given its modest 2.4m diameter mirror and the fact that the surface brightnesses of cosmologically distant objects decrease as (1 + z) 4 . For this reason, one of the early observations that was scheduled immediately after the first servicing mission of HST in December 1993 to repair spherical aberration was the re-imaging of the cluster of galaxies 0939+4713 at z = 0.4 that had been observed previously by Dressier et al. (1994) from both the ground and with the aberrated HST. The ten-orbit WFPC2 image demonstrated HST’s ability to resolve structure in distant galaxies, showing spiral and elliptical galaxies with a clarity approaching that achieved for the Coma cluster from the ground. Spirals are seen to be relatively abundant in 0939+4713, although they generally show an anomalous morphology.
{"title":"The Hubble Deep Field","authors":"Robert E. Williams","doi":"10.1017/S1539299600019912","DOIUrl":"https://doi.org/10.1017/S1539299600019912","url":null,"abstract":"Great progress has been made in recent years in understanding the large-scale structure of the universe. Recall that it is only within this century that we have even come to realize the existence of other galaxies as separate entities. Until the 1920’s the universe did not extend beyond the Milky Way. Novae and Cepheid variables changed that picture, and for the past 75 years extragalactic astronomy has been one of the most active and fertile areas of science. The concept of an expanding universe and its beginning in a Big Bang all derive from the discovery of external galaxies. Distant galaxies are faint and have small angular sizes, therefore their study has remained the province of the largest telescopes. Before the launch of Hubble Space Telescope, ground-based telescopes had succeeded in detecting distant galaxies out to redshifts of z ~ 1, and in establishing certain of their characteristics. But, there was uncertainty as to how much further HST could push the study of distant galaxies given its modest 2.4m diameter mirror and the fact that the surface brightnesses of cosmologically distant objects decrease as (1 + z) 4 . For this reason, one of the early observations that was scheduled immediately after the first servicing mission of HST in December 1993 to repair spherical aberration was the re-imaging of the cluster of galaxies 0939+4713 at z = 0.4 that had been observed previously by Dressier et al. (1994) from both the ground and with the aberrated HST. The ten-orbit WFPC2 image demonstrated HST’s ability to resolve structure in distant galaxies, showing spiral and elliptical galaxies with a clarity approaching that achieved for the Coma cluster from the ground. Spirals are seen to be relatively abundant in 0939+4713, although they generally show an anomalous morphology.","PeriodicalId":422890,"journal":{"name":"Highlights of Astronomy","volume":"208 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123528043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-06-01DOI: 10.1017/S1539299600011503
M. Hanner
Study of the dust in circumstellar disks around young stars is currently an extremely active area in astronomy. There is little doubt that accretion disks are a natural part of protostellar evolution. Much recent observational and theoretical work is giving us a clearer picture of the physical conditions in dust disks and their evolutionary progression. IRAS observations revealed that many main-sequence stars, such as p Pictoris, have circumstellar disks. But whether these disks are related to planetary formation is not yet understood. A portion of the dust in disks around young stars ultimately may be incorporated into planetary systems. Thus, study of the dust in our own solar system complements the remote sensing of protostellar regions and aids in reconstructing the evolutionary history of the dust. Since comets formed in the cold outer regions of the solar nebula, they may contain intact interstellar grains. As the comets lose material during passage through the warm inner solar system, some of these grains will be released into interplanetary space. Technical advances now allow analysis of individual micrometer or smaller grains in interplanetary dust particles and primitive meteorite samples. Isotopic anomalies and patterns of crystal growth in these particles are yielding tantalizing clues about the interstellar material incorporated into these solar system samples.
{"title":"Dust Around Young Stars: How Related to Solar System Dust?","authors":"M. Hanner","doi":"10.1017/S1539299600011503","DOIUrl":"https://doi.org/10.1017/S1539299600011503","url":null,"abstract":"Study of the dust in circumstellar disks around young stars is currently an extremely active area in astronomy. There is little doubt that accretion disks are a natural part of protostellar evolution. Much recent observational and theoretical work is giving us a clearer picture of the physical conditions in dust disks and their evolutionary progression. IRAS observations revealed that many main-sequence stars, such as p Pictoris, have circumstellar disks. But whether these disks are related to planetary formation is not yet understood. A portion of the dust in disks around young stars ultimately may be incorporated into planetary systems. Thus, study of the dust in our own solar system complements the remote sensing of protostellar regions and aids in reconstructing the evolutionary history of the dust. Since comets formed in the cold outer regions of the solar nebula, they may contain intact interstellar grains. As the comets lose material during passage through the warm inner solar system, some of these grains will be released into interplanetary space. Technical advances now allow analysis of individual micrometer or smaller grains in interplanetary dust particles and primitive meteorite samples. Isotopic anomalies and patterns of crystal growth in these particles are yielding tantalizing clues about the interstellar material incorporated into these solar system samples.","PeriodicalId":422890,"journal":{"name":"Highlights of Astronomy","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126566017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-08-01DOI: 10.1017/S1539299600006687
D. Dravins
The main features of solar and stellar activity cycles are summarized, followed by a discussion of some outstanding observational problems for the future.
总结了太阳和恒星活动周期的主要特征，然后讨论了未来一些突出的观测问题。
{"title":"Stellar Activity Cycles","authors":"D. Dravins","doi":"10.1017/S1539299600006687","DOIUrl":"https://doi.org/10.1017/S1539299600006687","url":null,"abstract":"The main features of solar and stellar activity cycles are summarized, followed by a discussion of some outstanding observational problems for the future.","PeriodicalId":422890,"journal":{"name":"Highlights of Astronomy","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122219142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1988-06-01DOI: 10.1007/978-94-009-0977-9_122
T. Matsumoto
{"title":"Submillimeter Spectrum of the Cosmic Background Radiation","authors":"T. Matsumoto","doi":"10.1007/978-94-009-0977-9_122","DOIUrl":"https://doi.org/10.1007/978-94-009-0977-9_122","url":null,"abstract":"","PeriodicalId":422890,"journal":{"name":"Highlights of Astronomy","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129977202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1986-11-01DOI: 10.1017/S1539299600010182
J. Mermilliod
The process of archiving photometric data and compiling catalogues is in principle easy to solve, but, in practice, does not appear so simple. Data retrieval may become difficult and inefficient if sufficient care is not taken to solve the general problems which are encoutered: (i) the lack of definition of fundamental identificators; (ii) the lack of coordinates for thousands of faint stars; (iii) the innacuracy of the identification and description of the components observed in double stars or multiple systems: A, B, C, AB, or BC; (iv) the fact that the number of observations is often not published.
{"title":"Archives of Photometric Data","authors":"J. Mermilliod","doi":"10.1017/S1539299600010182","DOIUrl":"https://doi.org/10.1017/S1539299600010182","url":null,"abstract":"The process of archiving photometric data and compiling catalogues is in principle easy to solve, but, in practice, does not appear so simple. Data retrieval may become difficult and inefficient if sufficient care is not taken to solve the general problems which are encoutered: (i) the lack of definition of fundamental identificators; (ii) the lack of coordinates for thousands of faint stars; (iii) the innacuracy of the identification and description of the components observed in double stars or multiple systems: A, B, C, AB, or BC; (iv) the fact that the number of observations is often not published.","PeriodicalId":422890,"journal":{"name":"Highlights of Astronomy","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1986-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123965096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1982-09-01DOI: 10.1017/S1539299600005402
P. Millman
The general nature of meteor spectra and the major meteor streams that are well represented in the currently available meteor spectra data bank are examined. Attention is given to resolution in meteor spectra obtainable with photographic and video-tape data, heights and velocities, and chemical abundances. The discussion also covers the use of photometric techniques for the determination of absolute luminosities in the spectrum lines of video-tape data. A procedure for the photometric calibration of digitized video-tape records is discussed.
{"title":"Current trends in meteor spectroscopy.","authors":"P. Millman","doi":"10.1017/S1539299600005402","DOIUrl":"https://doi.org/10.1017/S1539299600005402","url":null,"abstract":"The general nature of meteor spectra and the major meteor streams that are well represented in the currently available meteor spectra data bank are examined. Attention is given to resolution in meteor spectra obtainable with photographic and video-tape data, heights and velocities, and chemical abundances. The discussion also covers the use of photometric techniques for the determination of absolute luminosities in the spectrum lines of video-tape data. A procedure for the photometric calibration of digitized video-tape records is discussed.","PeriodicalId":422890,"journal":{"name":"Highlights of Astronomy","volume":"162 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1982-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121299710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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