Simultaneous measurements of Ca+ K,Ca+ H,Hα, Hβ, and He D3 emission in prominences

Simultaneously measured line intensities of Ca⁺ K and H, H, H and He D₃ are presented and compared with recent model calculations by Heasley and Milkey (1978). The model calculations are compatible with the observations. There is indication that the observed branching of the relation E(Ca⁺ K and H) E(H) depends on the widths of the Ca⁺-lines.     

Spectral analysis of Hα, Hβ, and Hγ lines of a white-light flare (3B/X6.1) on October 27, 1991

We have analyzed time series of H, H, and H line profiles taken from a 3B/X6.1 flare which occurred on October 27, 1991 in active region NOAA 6891. Each set of the spectra was taken simultaneously for the first 10 min of the flare event with a low and non-uniform time resolution of 10–40 s. A total of 22 sets of H, H, and H were scanned by a PDS with absolute intensity calibration to derive the dynamics and energetics of material in the flare region. Our results are as follows: (1) The Balmer line emitting region is accelerated downward to about 50 km s^-1 for the first 50 s and then is decelerated to about 10 km s^-1 for the next 150 s. (2) The radial velocity peak precedes the Balmer line intensity peak by about 40 s. (3) The total energy radiated from these Balmer lines is estimated to be 4.9 × 10²⁹ erg.     

The Hα/Hβ ratio in solar flares

We have measured the ratio of H to H central intensities in the peak kernels of 14 flares, using simultaneous filtergrams. The ratio is typically one with some scatter. By contrast, in stellar flares the ratio is about 0.8.     

A study of the nature of the Hα-emission stars LkHα112, 115, 118, and 119

The present study of the nature of the stars LkH112, LkH115, LkH118, and LkH119 is based on low-dispersion IDS spectra and photometric measurements in the wavelength range between 0.33 and 3.8 m. These stars are located in the direction of the extremely young open cluster NGC 6530 (Walker, 1957). The purpose of this study is, in general, to know whether they belong to the group of intermediate mass pre-main sequence objects, also known as Herbig Ae/Be stars, and, in particular, what special characteristics they possess. The result is as follows. The stars are very young; probably only LkH112 and LkH115 are members of the above-mentioned class of objects. The membership of LkH118 and LkH119 in this group is doubtful.Based on observations made at the European Southern Observatory, La Silla, Chile.     

Observations of the Orion Nebula in Hα, [NII] and Hβ lines

Monochromatic photographs of the Orion Nebula taken through narrow bandpass interference filters (Δλ=10 Å) centred on Hα, Hβ and [NII] lines are presented. Ratio contours of Hα/[NII] and Hα/Hβ are derived. They enable a detailed study of the point-to-point variation in ionization structure and temperature throughout the nebula. Dust located within the ionized gas is studied from the Hα/Hβ ratio which varies from point to point over the nebula. Its strongest concentration, apart in the obvious ‘dark bay’, occurs in a shell surrounding the exciting stars, with about 2′ of diameter. Close to Θ¹ Ori the Hα/Hβ ratio, corrected for interstellar reddening, is about 3.0 in good agreement with the predicted value (Brocklehurst, 1971). To account for these measures, the following arguments are proposed:

1. Dust grains are completely or partially destroyed in region close to the exciting stars.
2. Radiation pressure and stellar wind push the remaining dust up to some equilibrium distance outwards. The consequence of this action is obviously the formation of a ‘dust mantle’ which is seen as a ring in projection.

     

Hα, hard X-ray,and microwave emissions in the impulsive phase of solar flares

I have studied the observational relationship between the location of flare sites in active regions and three other observables, viz., H line width, hard X-ray burst parameters, and peak microwave fluxes. Results suggest that the strength of the magnetic field plays a role in governing the magnitudes of these emissions. Qualitative relationships are derived on the assumption of proportionality between the spectral maximum frequency of the associated microwave burst and the field strength in the microwave source.The relationship inferred between the power in thick target electrons (derived from the hard X-ray burst) and the column density of second-level hydrogen atoms (derived from the H line widths) is compared with calculations by Brown (1973) and Canfield (1974).The line widths observed for two white light flares suggest that a criterion for detectable continuum emission in disk flares is an H line width 20 Å.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.     

Umbral oscillations and penumbral waves in Hα

We present examples of umbral oscillations observed on Big Bear H filtergram movies and investigate the relation between umbral oscillations and running penumbral waves occurring in the same sunspot. Umbral oscillations near the center of the umbra are probably physically independent of the penumbral waves because the period of these umbral oscillations (150 s) is shorter than the penumbral wave period (270 s) but not a harmonic. We also report dark puffs which emerge from the edge of the umbra and move outward across the penumbra, and which have the same period as the running penumbral waves. We interpret these dark puffs to be the extension of chromospheric umbral oscillations at the edge of the umbra. It is suggested that the dark puffs and the running penumbral waves have a common source: photospheric oscillations just inside the umbra.     

EVIDENCE OF MAGNETIC RECONNECTION FROM Hα, SOFT X-RAY AND PHOTOSPHERIC MAGNETIC FIELD OBSERVATIONS

A conventional view of magnetic reconnection is mainly based on the 2-D picture of an X-type neutral point, or on the extension of it to 3-D, and it is thought to be accompanied by flux transport across separatrices (places where the field-line mapping is discontinuous). This view is too restrictive when we realize the variety of configurations that are seen flaring. We designed an algorithm, called Source Method (SM), to determine the magnetic topology of active regions (ARs). The observed photospheric field was extrapolated to the corona using subphotospheric sources and the topology was defined by the link between these sources. H flare brightenings were found to be located at the intersection with the chromosphere of the separatrices so defined. These results and the knowledge we gained on the properties of magnetic field-line linkage, led us to generalize the concept of separatrices to quasi-separatrix layers (QSLs) and to design a new method (quasi-separatrix layers method, QSLM) to determine the magnetic topology of ARs. QSLs are regions where the magnetic field-line linkage changes drastically (discontinuously when they behave like separatrices) and the QSLM can be applied to ARs where the photospheric field has been extrapolated using any kind of technique. In this paper we apply the QSLM to observed flaring regions presenting very different configurations and also to a decaying AR where a minor phenomenon, like an X-ray bright point (XBP), is observed. We find that the locations of flare and XBP brightenings are related to the properties of the field-line linkage of the underlying magnetic region, as expected from recent developments of 3-D magnetic reconnection. The extrapolated coronal field lines representing the structures involved in the analyzed events have their photospheric footpoints located at both sides of QSLs. Our results strongly support the hypothesis that magnetic reconnection is at work in various coronal phenomena, ranging from the less energetic ones to large-scale eruptions.     

色球耀斑Hα谱线轮廓不对称性研究

Hα谱线轮廓的不对称性是色球耀斑光谱观测中的重要特征,也是耀斑动力学过程的重要观测事实之一．以紫金山天文台太阳光谱仪的观测资料为依据,给出Hα谱线不对称性的典型轮廓．在考虑氢原子非热激发、电离的作用下,经验性地计算了不同大气模型下谱线的不对称性特征,并在此基础上,对观测谱线进行半经验的研究．结果表明, 色球区的向下运动能够产生Hα谱线的红、蓝不对称性,并可以再生具体耀斑的谱线不对称性特征．此外,不仅非热粒子的能流、谱指数大小以及速度场所处的高度对谱线轮廓有影响,耀斑大气的背景模型对谱线的轮廓也有一定的影响．     

云南天文台Hα全日面观测数据服务系统

云南天文台Hα全日面望远镜是云南天文台太阳观测的主要仪器之一。经过十几年的运行,望远镜积累了大量的观测数据,并且这些数据还在以每天1～2Gbyte的速度增长。为了保存这些数据,便于进行数据共享,建立了Hα全日面观测数据服务系统。硬件方面,采用DAS+NAS的存储方案;软件方面采用PHP+MySQL的方案。本系统的基本功能包括数据存储、数据备份、数据查询和数据下载,并已经正常运行了半年左右。介绍了这一系统的设计方案和基本结构。由于这一系统更多的是为澄江1m红外太阳塔的有关系统的设计提供经验和参照,因此在文中相关部分初步讨论了某些针对澄江1m红外太阳塔有关系统的考虑。     

New Hα-emission objects in the Cepheus region

Results are presented from a study of 31 new H -emission objects in the Cepheus region. The observations were performed with the 40 Schmidt telescope of the Byurakan Astrophysical Observatory in 1979, 1985, and 1989. Spectral plates were obtained with a 4° objective prism (-1100 Å/mm near H on Kodak 103-aE, 103-aF, III-aF and ORWO ZP-3 emulsions. Type RG1 and RG2 light filters were used during the observations.Translated from Astrofizika, Vol. 37, No. 2, pp. 219–228, April–June, 1994.     

色球耀斑Hα谱线轮廓不对称性研究进展

综述了近年来太阳色球耀斑爆发时Hα谱线不对称性的研究进展,着重讨论了光谱特征和与其对应的不对称性产生机制,以及利用大气半经验模型再生观测谱线轮廓不对称性等方面,并提出尚待解决的主要问题和进一步的研究方向。     

SN1996w Hα线的初步分析

据观测到的ＳＮ１９９６的Ｈα谱线的初步计算结果表明,该超新星可能是由一颗晚Ｂ９型超新星爆发形成的,爆发时的气壳质量可达０．００３１Ｍ⊙,径向膨胀速度为１１７０ｋｍ／ｓ。     

类星体HⅠ谱线的切仑柯夫红移与线强比I(Lyα)/I(Hβ)的关系

在切仑柯夫线发射理论的框架下,本文统一地讨论了类星体HI谱线的切合柯夫红移与线强比I(Lyα)/I(Hβ)之间的内在关系。忽略类星体宽线区气云外层光薄区中HI复合线的贡献,利用观测到的Lyα线相对于CIV线的相对红移,即切金柯夫红移,定出第二能级上粒子数布居R_2～0.02,利用观测的〈I(Hα)/I(Hβ)〉值定出参量x_β～14.0。在给定参量T～11000K时,HI的巴尔末线的切仑柯夫红移与线强比I(Lyα)/I(Hβ)同时与观测值相符甚佳,这对切仑柯夫线发射理论是一个有力的支持。     

Discrimination of α and β/γ interactions in a TeO2 bolometer

TeO₂ crystals have proven to be superb bolometers for the search of neutrinoless double beta decay in many respects. However, if used alone, they do not exhibit any feature that allows to discriminate an α energy deposit from a β/γ one. This fact limits their ability to reject the background due to natural radioactivity and eventually affects the sensitivity of the search. In this paper we show the results of a TeO₂ crystal where, in coincidence with its bolometric heat signal, also the luminescence light escaping the crystal is recorded. The results show that we are able to measure the light produced by β/γ particles, which can be explained as due to Cerenkov emission. No light is detected from α particles, allowing the rejection of this background source.     

紫金山天文台HαCCD图像实时采集和处理系统

本语文介绍了由南京大学天文系和紫金山天文台研究人员共同开发的ＨαＣＣＤ图像实时采集和处理系统。给出该系统硬件结构、软件各部分的功能、图像文件格式以及使用方法。     

几个活动区精细Hα结构的物理浅析

本利用紫金山天台赣榆站太阳精细结构望远镜拍得的高分辨率色球Ｈα照片，分析了三个典型活动区，中利用并检验了七十年代获得的磁图推导法则，应用自己的数值模拟知识和Ｚｗａａｎ对ＡＦＳ系新浮流区概括的特征，参考七十和九十年代总结的有关耀斑和Ｅｌｌｅｒｍａｎ Ｂｏｍｂ的再现规律，逐日分析活动区发展，定出其内部的中性线位置，提出简单和复合中性线的区分，由ＡＦＳ系和亮谱斑同时出现判断新浮流区，从近离带图找等     

Hα全日面太阳图像云污染的去除

Hα全日面太阳图像对太阳物理研究有着重要的意义,但其观测过程中可能受天气的影响,导致观测图像含有云层覆盖的污染。主要通过对这种Hα全日面太阳图像的云污染进行处理,从而得到较为清晰的太阳活动细节。具体算法为:首先将含云污染的图像扣除模板图像的标准临边昏暗轮廓,然后对其进行中值滤波获得云层图像,最后在原始图像上扣除云层图像得到修复后的全日面图像。实验证明此方法可以有效地去除Hα全日面太阳图像上的云污染,并对太阳活动区域影响较小。     

Spectroscopic study of Hα-emission objects in IC 1396

Spectral observations of 53 H-emission objects of the HII-region IC 1396 were carried out with moderate resolution using the 2.6m telescope of the Byurakan Astrophysical Observatory. Factor analysis of this observational material indicates that there are two dominant factors. Factor 1 (Fig. 1), which is the more significant factor, resembles the spectrum of a star of spectral type F5 with a strong H line in absorption. Factor 2 (Fig. 2), in contrast, appears as a later-type spectrum with H and H in emission. The result obtained can be explained by the transient nature of the H-emission.Translated fromAstrofizika, Vol. 37, No. 3, 1994.     

Hα-wide and narrow-band photometry of R canis majoris

H wide and narrow-band photoelectric observations of the eclipsing binary R CMa were made at the Biruni Observatory between 18 February to 2 March, 1983. The light curves obtained from the observations are analysed according to Kopal's method for the orbital elements by using frequency-domain techniques. A total of obvervations was secured and light curves were formed from these data. From the available evidence it appears likely that an exchange has taken place on the angle of the first contact and is probably continuing at the present time in the system. New geometric and photometric elements are derived and new value for the angle of the first contact is also given.Contribution No. 11, Biruni Observatory.