桂林一次强下击暴流成因分析     

李彩玲  蔡康龙  黄先香  植江玲  陈志芳  麦文强 《气象》2021,47(2):242-252

2019年3月21日广西桂林市临桂区发生一次极端大风天气过程(以下简称"3·21"临桂大风),当日21:13临桂观测站记录最大阵风风速为60.3 m·s-1(17级).通过风灾现场调查判断这是强度为EF2级的微下击暴流过程.应用常规观测资料以及加密自动气象站、探空、多普勒雷达等资料,分析了"3·21"临桂大风的环流背景...  相似文献   

Photometric membership and metallicities of red giant candidates in selected open clusters     

J.J. Clari  A.E. Piatti  J.‐C. Mermilliod  T. Palma 《Astronomische Nachrichten》2008,329(6):609-618

As part of a long‐term project to determine abundances and astrophysical properties of evolved red stars in open clusters, we present high‐precision DDO photoelectric observations for a sample of 33 red giant candidates projected in the fields of nine Galactic open clusters. These data are supplemented with UBV photoelectric photometry of 24 of these stars as well as with CORAVEL radial‐velocity observations for 13 red giant candidates in four of the clusters. We also present Washington photoelectric photometry of a small sample of red giant candidates of the open cluster Ruprecht 97. The likelihood of cluster membership for each star photometrically observed and for 23 additional red giant candidates with UBV and DDO data available in the literature, is evaluated by using two independent photometric criteria. Nearly 82% of the analysed stars are found to have a high probability of being cluster giants. Photometric membership probabilities show very good agreement with those obtained from CORAVEL radial velocities. While E (B –V) colour excesses were determined from combined B – V and DDO colours, calibrations of the DDO system were used to derive MK spectral types, effective temperatures and metallicities. The derived DDO metallicities range between values typical of moderately metal‐poor clusters ([Fe/H] = –0.19) to moderately metal‐rich ([Fe/H] = 0.25) ones. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Spectroscopic verification of suspected planetary nebulae. IV.     

L. Kohoutek  R. Pauls 《Astronomische Nachrichten》2001,322(3):171-178

Verification of 7 objects as PNe (Table 1/A) as well as misclassification of 5 objects as PNe (Table 1/C) are discussed according to our CCD spectra; the status of 4 objects (Table 1/B) remains uncertain. In Table we give the estimates of line‐strengths and the measured intensities of emission lines as well as the derived hel. radial velocities and their standard deviations.  相似文献   

Spectroscopic verification of suspected planetary nebulae. III.     

L. Kohoutek  R. Pauls 《Astronomische Nachrichten》1994,315(6):409-412

Classification of eight objects as planetary nebulae (Table I/A) was confirmed according to our image tube spectra; as to further two objects (Table 1/B) their status remains unclear. In Table 2 we give estimates of line-strengths, derived heliocentric radial velocities and their standard deviations.  相似文献   

Kinematics of 11 Bidelman's weak‐lined stars     

A. Bartkevi ius  J. Sperauskas 《Astronomische Nachrichten》2003,324(5):460-463

Radial velocities obtained with the CORAVEL‐type spectrometer are presented for 11 Bidelman's weak‐lined stars, classified from moderate dispersion objective prism spectra. Standard errors of the measurements are smaller than 1 km/s. For five of these stars, measured in the Vilnius photometric system, only small metal deficiency is established. Kinematically, most of the stars belong to the thin disk and only two stars, HD 71185 and BD +75° 641, are consistent with membership of the thick disk population.  相似文献