太阳黑子本影振荡的周期测量

本影振荡是出现在太阳黑子内的一种常见现象,精确测定它们的振荡周期对于理解黑子的结构和演化有着重要意义。应用快速傅里叶变换方法对空间望远镜HINODE在2007年5月1日观测的活动区AR10953内的黑子本影数据进行了细致的分析,结果发现在该活动区本影内存在一种典型的3 min振荡,其振荡周期约为154 s。     

太阳黑子本影点的分析研究

本文利用紫金山天文台太阳室200mm赤道仪的照相装置1980年所观测到的10个不同的太阳黑子的17张高分辨率的白光照片,我们辨认了30个本影点,并对它们进行测量,计算及分析。     

恒星黑子的观测

本文对恒星黑子的观测方法和结果作了综合评述。介绍了恒星黑子温度的多色测光测定方法；黑子大小，温度和分布情况的测光畸变波黑子模型解，和高信噪比谱线轮廓多普勒成像方法；以及黑子寿命观测统计方法等的基本原理和研究进展。对已取得的有关恒星黑子的观测分析结果作了概括，与太阳典型黑子情况作了对比，并对恒星黑子的巨黑子，极区黑子以及长寿命黑子特殊性作了讨论，对需要进一步观测研究的问题作了总结。     

云南天文台太阳黑子相对数可靠性探讨

对云南天文台１９６４年１月至１９９６年１２月期间的太阳黑子相对数与《Ｓｏｌａｒ－ＧｅｏｐｈｙｓｉｃａｌＤａｔａ》上对应的数据进行了比较,结果发现,云南天文台的黑子相对数,在整体上及各个太阳活动周内与《Ｓｏｌａｒ－ＧｅｏｐｈｙｓｉｃａｌＤａｔａ》上的数据在较大程度上是线性相关,相对误差一般小于１０％,在第２１太阳活动周内,二者符合得极好,第２０太阳活动周内,符合较较好（统计上略微偏小）,第２２太阳尖     

太阳黑子穿过同磁极性大黑子的观测

本文利用紫金山天文台精细结构望远镜拍摄的优质Ｈａ线心和离带照片，分析了新浮黑子活动区１９９０年１２月５日至９日磁结构演化及黑子的自行运动。我们观测到了一黑子穿过另一同极性大黑子这一非常少见的现象。     

论云南天文台黑子描迹观测数据的稳定性

本文求出1960-1977年间云南天文台的三个主要观测者的黑子相对数K_R、均方误差m_R,以及黑子圆面积数系数K_A、均方误差m_A。K±m随时间变化,在1974—1977年,K_R为0.65～0.75,m_R在2.2～3.7％之间(表1结果),K_A为0.92～1.09,m_A在3.7—7.5％之间(表6结果)。所求出的结果,可供数据的使用者参考。 为提高数据资料的质量,利用所求得的结果,对观测者的数据使用累计K值的办法,以及观测人员应有相对稳定性等问题进行了讨论。     

紫金山天文台55 yr手绘黑子数据系统差分析

对紫金山天文台(简称紫台)自1954年至2011年共55 yr的手描黑子图进行了数字化.将紫台太阳黑子相对数(PRSN)和黑子群数(PGSN)与国际太阳影响数据分析中心(SIDC)中的对应数据(月平均太阳黑子相对数(IRSN)和月平均黑子群数(IGSN))进行对比研究,发现:(1)紫台黑子数据与SIDC黑子数据有很强的正相关性,说明紫台黑子数据的可靠性;(2) PRSN和IRSN、PGSN和IGSN的系统偏差分别处于7%左右、5%左右,紫台数据与SIDC数据在活动周的极小期的差异性显著大于极大期;(3)紫台的视宁度从1995年开始变差,直接导致了PRSN (PGSN)与IRSN (IGSN)的比值明显变大,表明视宁度的变化影响了紫台黑子的观测质量.     

Enhanced Joule Heating in Umbral Dots

We present a study of magnetic fields in umbral dots (UDs) and its consequences on the Joule heating of the UDs. Hamedivafa (Astron. Astrophys. 407, 761, 2003) studied the Joule heating using the vertical component of the magnetic field. In this paper the magnetic field profile in the UDs is investigated by including a new azimuthal component of the magnetic field that might explain a relatively large enhancement of Joule heating causing higher brightness near the circumference of the UDs.     

Eclipses and Occultations of Galilean Satellites Observed at Yunnan Observatory in 2003

We describe and analyze observations of mutual events of Galilean satellites made at the Yunnan Observatory in February 2003 from CCD imaging for the first time in China. Astrometric positions were deduced from these photometric observations by modelling the relative motion and the photometry of the involved satellites during each event.     

A Flare and Umbral Flashes in a Sunspot

We studied the evolution and dynamic processes in the chromosphere above a sunspot umbra. A relatively rarely occurring phenomenon of bright long-lasting emission observed in the umbra of a unipolar sunspot of the AR 9570 group on August 11, 2001 was investigated. It was found that during the course of the observation, emission was spreading, gradually occupying nearly the entire sunspot umbra. Based on the analysis of the observations from other observatories, we arrived at the conclusion that the bright emission was a sympathetic flare that occurred in the sunspot umbra. It was assumed that there occurred an interaction with a neighboring, rapidly evolving group that exhibited subflares on the day of observation. In the same umbra, there was taking place an oscillatory process of the type of umbral flash (observations from August 11 and 12, 2001). The characteristics of the oscillatory process in the presence of the flare were studied. As the bright emission propagated in the sunspot umbra, brightness fluctuations ceased to be seen in the umbral flashes against the background of this brighter emission. The character of velocity variations did not change substantially, although the oscillation amplitude did decrease.     

太阳黑子本影振荡的多波段观测

基于多波段的观测数据, 研究了黑子本影振荡在太阳大气不同高度或温度的振荡特征. 目标黑子发生在2017年9月15日, 位于活动区12680. 多波段的观测数据包括AIA (Atmospheric Imaging Assembly)的极紫外成像及IRIS (Interface Region Imaging Spectrograph)的紫外光谱和成像. 在太阳黑子的本影位置, AIA 1700 Å 光变曲线的振荡周期约为(4.2士0.8) min,而AIA 1600 Å、171 Å和193 Å光变曲线的振荡周期约为(2.8士0.3)min. IRIS的Mg II h和k谱线及远紫外成像(2796 Å)都表现为(3.1士0.5) min的准周期振荡,而谱线Si IV 1393.76 Å的振荡周期约为(2.9+0.4)min.观测结果说明黑子本影的振荡周期随着太阳大气高度的升高而逐渐减小.较短的周期可认为是3 min振荡,很可能与黑子本影上方的慢磁声波有关,它起源于温度极小区并向上传播到日冕.较长的周期可解释为光球的5 min振荡,与太阳的P模振荡有关.     

云南天文台天文新技术实验室工作进展

云南天文台新技术实验室成立至今已走过十几个年头，这些年来为云南天文台的发展作出了很多的贡献。从我国的第一套ＣＣＤ系统到天文遥在观测，不但在天文技术领域有所发展，而且目前拥有一支老中青相结合的相对稳定的队伍。本文主要回顾了新技术室这些年来的主要工作。     

云南天文台的精密定轨系统

概述了精密定轨轮廓及其重要性,重点介绍了云南天文台的精密定轨系统,包括处理流程、所采用的动力学模型及其参考系的选取,并介绍了残差分析方法,用以剔除"野值"以及分析测站数据质量。运用该精密定轨系统,分析处理了LAGEOS从2004年1月1日到2004年10月26日的全球SLR数据以及AJISAI从2008年5月3日到2009年2月26日全球SLR数据,每3天一个弧段,LAGEOS的测站总RMS不超过3cm,主要集中在1.5cm附近,AJISAI的测站总RMS不超过6cm,主要集中在3.5cm附近,与同期空间研究中心CSR的RMS相当,表明云南天文台用于精密定轨的系统运算结果是可信的。     

从窗口看云南天文台

简要总结了云南天文台２０年来的科研工作及人才培养情况，并对未来的发展提出了设想。     

Identification of AlF Molecular Lines in Sunspot Umbral Spectra

High resolution FTS sunspot umbral spectra from NSO/Kitt Peak were used to detect rotational lines due to 11 electronic transitions of the molecule AlF, in the wavelength region 4400 – 9000 Å. The presence of lines due to bands C – A (0,0), (0,1), (0,2) and (1,2), D – A (0,0) and (0,1), F – A (0,0), G – A (0,0), and F – B (0,0) is confirmed. Further, the presence of lines due to C – A (1,0) and (1,1) transitions is treated as doubtful because of heavy blending in the region, by rotational lines of TiO. Among the identified lines, those which are well resolved were selected for measurement of equivalent widths. The measured values for the bands D – A (0,0) and F – A (0,0) were used to estimate the respective effective rotational temperatures to be 1240 ± 120 K and 2390 ± 400 K.     

Presence of C2 molecular Lines in Sunspot Umbral Spectra

The C₂ molecule is well known for its astrophysical importance. The radiative transition parameters that include Franck-Condon (FC) factor, r-centroid, electronic transition moment, Einstein coefficient, absorption band oscillator strength, effective temperatures and radiative life time have been estimated for the Swan band $(d^3{\Pi }_g-a^3{\Pi }_u)$ system of C₂ molecule for experimentally observed vibrational levels using RKR (Rydberg–Klein–Rees) potential energy curve. The lifetime for the d³Π_g state of C₂ molecule was found to be 82.36 ns for the $v^{\prime }=0$ level. A reliable numerical integration method has been used to solve the radial Schrödinger equation for the vibrational wave functions of upper and lower electronic states based on the latest available spectroscopic data and known wavelengths. The estimated radiative transition parameters are tabulated. The effective vibrational temperature of Swan band system of C₂ molecule is found agreed with the effective rotational temperature from photosphere spectrum. Hence, the radiative transition parameters and effective temperatures help us to ascertain the presence of C₂ molecule in the interstellar medium, photosphere and sunspots.