1H2214+589/3G71的光谱特征:3G71可能是一颗Herbig Ae/Be星

We present evidences showing that the Be star 3G71, proposed as the optical cou- nterpart of the Be / X-ray binary source 1H2214 + 589, may be a Herbig Ae / Be star. These evidences can be summarized as follows. 1. We made spectroscopic observations by using a CCD spectrograph with dispersi- ons 50 A / mm and 195 A / mm at the BAO 2.16m telescope. Analysis of the optical spectra of 3G71 indicates: a. Forbidden lines, such as [OI] 6300 and 6363 A, [FeII] 5527, 4889, 4814, 4415, 4359 and 4304 A, are present in the spectra (Fig.2a, Fig.2b). b. The Hα emission line is unusually strong. Its equivalent width is sometimes more than 100 A (Fig. 1). The photospheric absorption lines of hydrogen are very wide. In the case of Hβ, the distance between two wings amounts to 60 A (Fig.2a, Fig.3). 2. We have performed cross-identification between HST GSC catalogue and IRAS Point Source Catalogue and found the IRAS point souree counterpart of 3G71 to be 2248 + 6058. Its equatorial coordinates (at equinox 1950.0) are 22h24m53s.8 and +60°58′ 15″, while those given by the GSC catalogue are 22h24m53s.37 and +60°58′13″.1. The differences are merely 0.4s and 2″, being less than the uncertainty ellipse (major axis: 11″, minor axis: 6″) given in IRAS PSC. Table 1 lists the flux densities quoted from IRAS GSC and the deduced IRAS IR magnitudes. It is clear from the table that 3G71 has a very large IR color excess, since the V magnitude of 3G71 found from GSC is 12.2 and its V-[25]=+12.47, which is much larger than that expected for classical Be stars and satisfies the criterion for the Herbig Ae / Be stars given by Hu et al., i.e., V-[25] > 7. 3. Using Palomar sky survey map, we have made a search for a nebulosity in the immediate vicinity of 3G71 and actually discovered a bright nebula, at whose center 3G71 is just located. Its diameter is about 1 are-minute. It is concluded from the characteristics of 3G71 mentioned above that 3G71 may be a Herbig Ae / Be star.

Herbig Ae/Be星的尘埃壳层形态研究

我们使用Kurucz恒星大气模型以及黑体模型对22颗Herbig Ae/Be星的紫外数据、IRAS观测数据、地面光学及近红外测光数据资料等进行了拟合计算,用能量平衡方法进行了统计分析,得出Herbig Ae/Be星的尘埃壳层为盘状的结论.

Study of the Long-term BVR_(c)I_(c) Photometric Variability of Eight PMS Stars in the Young Open Cluster Trumpler 37

This paper reports results from our long-term BV(RI)_(c) photometric CCD observations of eight pre-main sequence stars collected from 2008 June to 2022 October.These stars are located in the young open cluster Trumpler 37,in the field of GM Cephei.The observational data indicate that all stars from our study exhibit variability in all-optical passbands,typical for young stars.In this paper,we describe and discuss the photometric behavior of the stars and the possible reasons for their variability.For two of the objects,we identified periodicity in their light variation.

ICP-AES法测定八角茴香中14种微量元素

采用微波消解法处理八角茴香样品,电感耦合等离子体原子发射光谱(ICP-AES)法测定其中Mo,Cu,Cd,Mg,Pb,Zn,Mn,Fe,Al,Ni,Sr,As,Cr和Se 14种微量元素的含量。选择ICP仪器最佳测定条件为射频功率1300 W,载气流量0.2 L/min,冷却气流量15 L/min,等离子体气流量0.8 L/min,试样提升量1.5 mL/min。方法检出限为0.0002～0.006μg/mL,回收率为95.08%～105.20%,相对标准偏差(RSD)均小于3.71%。此法简便、快速、灵敏度高、准确性好、对环境污染小,可多元素同时测定。

Spectral study of V565 Mon: probable FU Ori-like or chemically peculiar star

We present a detailed spectroscopic study of pre-main sequence star V565 Mon,which is the illuminating star of the Parsamian 17 cometary nebula.Observations were performed with the 2.6 m telescope in Byurakan Astrophysical Observatory on 2018 February 15.Radial velocities and equivalent widths of the most prominent lines of V565 Mon are presented.We build the spectral energy distribution and estimate the main parameters of the star,for example the obtained bolometric luminosity of V565 Mon is L_(V565)≈130 L_(⊙).Considering all features of V565 Mon,we come to the conclusion that this young intermediate-mass star belongs to some intermediate class between T Tau and HAeBe stars.Very unusual for a young star is the presence of strong absorption BaⅡlines in the spectrum.Possible explanations on this issue are discussed.Hence,we think that V565 Mon is a unique example,which can help to understand some open questions involved in the problem of nucleosynthesis in young stars.

BV(RI )c photometric study of three variable PMS stars in the field of V733 Cephei

This paper reports results from the first long-term BV(RI)c photometric CCD observations of three variable pre-main-sequence stars collected during the period from February 2007 to January 2020. The investigated stars are located in the field of the PMS star V733 Cep within the Cepheus OB3 association. All stars from our study show rapid photometric variability in all-optical passbands. In this paper, we describe and discuss the photometric behavior of these stars and the possible reasons for their variability. In the light variation of two of the stars, we found periodicity.

Variability of emission lines in the optical spectra of the Herbig Be binary system HD 200775

In our previous papers we have improved the value of the orbital period of the binary Herbig Be star HD 200775 and showed that the [O I] and Si II 6347 and 6371 ?A emission lines displayed variations which correlate with the orbital period. In this paper we provide evidences that other broad emission lines of metals in the spectra of HD 200775 also exhibit variability, which is probably related to the orbital cycle of the binary. Analysis was performed based on the high-resolution spectral data collected over a time span of 6 years at the Kourovka Astronomical Observatory of the Ural Federal University(Russia) and the Three College Observatory of the University of North Carolina at Greensboro(USA) as well as archival spectral data compiled since 1994. We report new data points in the radial velocity curve of the He I 5876 ?A line near the extremal values of the radial velocity.

Long-term BV RI photometric light curves of 15 PMS stars in the star-forming region IC 5070

This paper reports results from the multicolor photometric observations of 15 pre-main sequence stars collected in the period September 2010-October 2017. The stars from our study are located in the star-forming HII region IC 5070. These objects were previously detected as either emission line stars, flare stars, T Tauri variables or Herbig Ae/Be stars. Photometric observations, especially concerning the long-term behavior of the objects, are missing in the literature. We present the first photometric monitoring for all stars from our study. The analysis of the obtained BV RI photometric data allows us to draw the conclusion that all investigated objects are variable stars. In the case of LkHα 146,we identified previously unknown periodicity in its photometric variability.

Long-term Photometric Study of the Pre-main Sequence Star V1180 Cas

In this paper results from the optical photometric observations of the pre-main sequence star V1180 Cas are reported.The star is a young variable associated with the dark cloud Lynds 1340,located at a distance of 600 pc from the Sun in the star-forming region in Cassiopeia.V1180 Cas shows large amplitude variability,interpreted as a combination of accretion-induced and extinction-driven effects.Our data from VRI CCD photometric observations of the star were collected from September 2011 to February 2022.During our monitoring,we recorded several brightness dips with large amplitudes of up to 5 mag(I band).At the same time,increases in brightness over periods of several weeks have also been recorded.In this paper,we compare the photometric data obtained for V1180 Cas with observations of other low-mass pre-main sequence objects.

Long-term V(RI) CCD photometry of pre-main-sequence stars in the association Cepheus OB3

Results from optical CCD photometric observations of 13 pre-main-sequence stars collected during the period from February 2007 to November 2020 are presented.These stars are located in the association Cepheus OB3,in the field of the young star V733 Cephei.Photometric observations,especially concerning the long-term variability of the stars,are missing in the literature.We present the first longterm V(RI)c monitoring for them,that cover 13 years.Results from our study indicate that all of the investigated stars manifest strong photometric variability.The presented paper is a part of our program for the photometric study of pre-main-sequence stars located in active star-forming regions.

Large-Scale Distribution of Herbig-Haro Objects in Taurus

We report our new results on Herbig-Haro (HH) objects in the star forming region of Taurus from a wide-field survey with the 60/90 cm Schmidt telescope of the Beijing Astronomical Observatory. This survey using CCD imaging with a narrow band [SII] filter and an intermediate band [BATC10] filter covered approximately 30 square degrees in Taurus. Besides confirming the known HH Objects in the region, we discovered seven new HH candidates, and groups. Six of these are HH 701A-B, HH 702A-D, HH 703, HH 704A-D, HH 705, HH 706 and the seventh is a group, a new component of HH 319, labeled HH 319B-D. Based on the large-scale distribution of pre-main-sequence (PMS) stars in Taurus, we analyze statistically the most probable distance from the HH objects to each PMS star, from which we estimate the typical timescale of these HH objects to be between (1.3?2.0)×104 yrs; and we also obtain the birth rates of HH objects: 0.447±0.198 for Class I PMS stars, 0.360±0.222 for Class II PMS stars, and ?0.148±0.234 for Class III PMS stars.

A Study of the Energy Sources of Herbig-Haro Objects

We make a statistical study of the energy sources of high-velocity phenomena, Herbig-Haro (HH) objects. IRAS counterparts of HH objects are identified. Their colors, brightness, geometric relation to the RH objects and SED are analysed. The sources are found to be concentrated in a band-shaped region in the IRAS color-color diagram. We suggest an explanation of thick surrounding material for this distribution. We propose a new method for identifying the energy sources based on color arid brightness. This method is applied to more than 200 HR objects whose energy sources are still unknown. Finally, a group of very young stellar object candidates which have similar properties to the RH energy sources is picked out. Their large-scale distribution is discussed.

八角中微量元素含量测定方法的探讨

八角是南亚热带珍贵的天然香料。结合干法、湿法、微波消解等溶样方式,电感耦合等离子体发射光谱仪、原子吸收分光光度计对广西八角中钙、钾、镁、铁、钠、铜、锶等7种微量元素进行测定。

δScuti变星和相关天体

δ Scuti型变星是赫罗图上 A3～F5区间的主序及其以上的一种周期短于0.3 d的单周期或多周期小变幅脉动变星。与它们相关的变星有矮造父变星、γDol变星、蓝离散星、金属线星、A型特殊星、λ Boo变星和 δ Del变星。有些赫比格Ae/Be星也存在类似的脉动。对自 1964年起的研究工作进行了系统的总结,给出了1995年后新发现的相关变星数和最可靠的周期变化表,提出应当用双星轨道光时效应来解释实测得到的变星周期变化中的幅度很大的成分。统计表明自转越快变幅越小,因此年轻星团中不可能存在大变幅变星。变幅随周期的分布有3个极大值,最大变幅是周期0.17d处的1.0mag。恒星系统内变星的平均周期越短系统的年龄越大,金属丰度也越低。

大尺度赫比格-哈罗天体的光学研究进展

近期大视场ＣＣＤ成像观测表明。由年轻星激发的部分赫比格－哈罗（ＨＨ）天体的尺度范围 超过 １ｐｃ，比过去认识的 ＨＨ天体的尺度大了一个量级。目前的观测己经发现 ｐｃ尺度的 ＨＨ天 体有数十个，表明ＨＨ天体达到ｐｃ尺度是很普遍的，这将深刻地改变人们对年轻星与其周围环境 作用的认识．综合评述了ｐｃ尺度ＨＨ天体的观测性质，讨论了巨ＨＨ天体对恒星形成的重大意 义及其对周围星际介质的物理和化学影响．

赫比格-哈罗天体高分辨观测研究进展

赫比格－哈罗天体（ＨＨ天体）包含了有关原恒星吸积和抛射过程的许多重要信息。ＨＨ 天体高分辨观测研究取得了一系列新进展：分辨出激波峰面、马赫盘和辐射冷却区；分辨出 喷流节点的结构，发现它们大多是内工作面，而不是由Ｋｅｌｖｉｎ－Ｈｅｌｍｈｏｌｔｚ不稳定性所产生 的斜激波；发现喷流宽度随到激发源距离的减小仅缓慢减小，对喷流的准直和加速模型提供 了限制条件； ＨＨ天体在小尺度上尚有复杂的激发结构、对这些进展进行了评述。

HD 104237,εCha和HD 100546的演化状态

根据Ｈｉｐｐａｒｃｏｓ的资料和ＴＤ－１对εＣｈａ和ＨＤ１００５４６的紫外观测资料讨论了εＣｈａ、ＨＤ１０４２３７和ＨＤ１００５４６在赫罗图上的位置以及它们的演化状态．

Simultaneous photometric and spectral analysis of a new outburst of V1686 Cyg

We present an analysis of the optical observations of Herbig Ae/Be(HAeBe)star V1686 Cyg,which is associated with a small isolated star-forming region around HAeBe star BD+40?4124.We observed this star as a part of our project investigating young eruptive stars.Observations were conducted on the 2.6-m telescope of Byurakan Observatory from 2015 to 2017.In this period,we obtained direct images of V1686 Cyg and 14 medium-and low-resolution spectra.In the course of observations,we noticed that this star underwent an atypical brightness outburst.After data reduction,we found that the full rise and decline in the brightness of V1686 Cyg had an amplitude of almost 3 magnitudes and lasted about 3 months.We were also able to track changes in the stellar spectrum during the outburst,which are correlated with the photometric variations.

Discovery of an Optical Jet in the Rosette Nebula: Rosette HH2

We report on the discovery of an optical jet - Rosette HH2 - in the RosetteNebula. The jet system bears unique features for residing at the center of a giant HII region, andits energy source is visible with apparently very low extinction along the line of sight. Unlikemost other Herbig-Haro jets, this jet indicates a high-excitation origin, and its extended portionshows a seemingly intact structure, instead of normally a shocked working surface, which isattributed to photoablation.

Optical Spectroscopic Monitoring Observations of a Young Binary Z CMa

The results of optical spectroscopic monitoring observations of a young binary system, Z CMa, are presented in this study. Z CMa consists of a Herbig Be star and an FU Orionis object, and it shows irregular light variation in the quiescent phase and exploding brightening in the outburst phase. Medium-resolution spectra were obtained on 21 nights between 2015 and 2019 using the Nayuta telescope in Japan. We also used five high-resolution spectra, obtained between 2008 and 2011, with the Keck Telescope. During the outburst phase, the intensity of the He I absorption line increased with an increase in the luminosity of the system. Because the He I absorption line is a characteristic feature of an early-type star, we considered that the outbursts were caused by the Herbig Be star. The equivalent widths of the [O I] line decreased with an increase in the luminosity of the system. We claim steady mass loss at the rate of The intensities of the Hα and Fe II emission lines did not change during the outbursts. However, the line intensities increased with an increase in the luminosity of the system in the quiescent phase. We consider that those lines are attributed to the FU Orionis object and the light variations in the quiescent phase were caused by the FU Orionis object.