Searches for HH-objects and Emission Stars in Star Formation Regions. II. The Region of GM1-61 and V453 Ori

Observations of objects lying in the dark cloud L1582A, which contains the cometary nebulae GM1-61 and V453 Ori, are reported. Five previously unknown HH-objects are discovered in this region; they appear to form several flows. The morphology of the nebulae is examined and possible sources of the HH-flows are discussed. Another reflecting nebula is found that is visible mainly in the infrared.     

IRAS 17213-3841:晚型富碳星还是早型发射线星?

IRAS 17213-3841作为富碳星列于新版碳星星表中．然而该星的IRAS低分辨率光谱显示富氧的硅酸盐发射特征；光谱观测结果表明，该星是一个接近零龄主序的，光谱型为O9／B0的早型发射线星，而不是碳星，因此应从碳星星表中剔除．此外，将它证认为碳星的近红外-IRAS双色图方法并不是一个完全可靠的方法，用这一方法来证认碳星必须十分小心．     

Search for Star Groups in the Solar Neighborhood

Two methods are proposed for finding star groups in coordinate and velocity spaces, which were used to investigate stars of the Hipparcos Catalog with known radial velocities in the solar neighborhood with a radius of 125 pc. Thirteen probable nonrandom star groups in coordinate space and five moving groups in velocity space were found. These results are compared with the results of other authors.     

Spots and Active Regions on Emission Stars. III. LQ Hya

Quasisimultaneous photoelectric, polarimetric, and spectroscopic observations of the active single red dwarf LQ Hya are presented. The photometric variability of LQ Hya is fully described by a zone model. Spotted regions occupy up to 25% of the entire surface of the star with a temperature difference of 800 K between the spots and the calm photosphere. The spots are localized in the middle and low latitudes. A cyclical variation is observed in the total areas of the spotted regions and in the average latitude of the spots. The most spotted regions, local magnetic fields, and chromospherically active regions tend to concentrate in the same distinct active longitudes.     

Search for HH-Objects and Emission-Line Stars in Star Forming Regions. I. The Lynds 1340 Dark Cloud

Spectroscopic and photometric observations of objects embedded in the L1340 dark cloud are reported. An entire series of HH-objects in the RN07 region was discovered, including new ones that form two or three flows. It is suspected that several cases of HH emission are included. In addition, 14 emission stars, of which 11 are new, were found in this region. Most of these stars are localized inside the RN07 nebula which, therefore, encompasses a compact cluster of very young stars. Other nebulous objects inside the L1340 cloud, many of which are associated with IR sources, are described. As a whole, this cloud represents an extremely active star forming region.     

大质量星形成区的高速气体搜寻

在红外天文卫星点源表中选取了具有陡远红外谱的９７个源及其它８个红外源,用射电天文联合实验室紫金山天文台青海站的１３７ｍ望远镜,进行了ＣＯ（Ｊ＝１－０）的观测．结果在１０２个源中测到了ＣＯ辐射,有９个源参考位置难以确定,２１个源有多重成分,在其余７２个源中有２９个具有高速气体,其中１８个是新测到的双极外向流候选者,对其性质及与年轻星体的关系作了简要讨论．     

Search for HH objects and emission stars in star formation regions. IV. New Herbig-Haro flows and objects associated with cometary nebulae

As part of a project to search for new Herbig-Haro (HH) objects in star formation regions, observations are reported on the neighborhoods of five cometary nebulae: MacC H12, MacC sH15, GM 1-14, RNO 33, and Pars 17. We have been able to identify 9 previously unknown HH objects in those regions. Almost all of these objects belong to directed flows whose sources are, with high probability, the central stars of these nebulae. In the cases of MacC H12 and GM 1-14, the outflows have a distinct bipolar structure. The sources of the outflows are located on a J-H/H-K diagram in order to classify them. __________ Translated from Astrofizika, Vol. 51, No. 1, pp. 15–27 (February 2008).     

氦白矮星与小质量主序星并合及脉动热亚矮星的形成

sdBVrs型热亚矮星是一类特殊的热亚矮星,观测显示它们同时具有p模和g模的脉动.目前这一类热亚矮星的演化起源仍然缺乏完备的解释.对氦白矮星与小质量主序星并合模型进行详细计算表明,并合模型的结果符合sdBVrs型热亚矮星的表面有效温度、重力加速度等观测特征,并且能够激发出稳定的p模和g模脉动.因此,氦白矮星与小质量主序星并合是形成sdBVrs型热亚矮星可能的渠道之一.     

Searches for HH objects and emission stars in star formation regions. V. Two new cometary nebulae in Perseus

A small region surrounding the emission star LkHα 326 in the Perseus dark cloud is studied in the optical range. Two new cometary nebulae are described and their relationship to the Herbig-Haro objects in this region is examined. An HH-jet is discovered near the central star of one of these nebulae. Six emission stars, of which four are new, are detected by slitless spectroscopy. __________ Translated from Astrofizika, Vol. 51, No. 2, pp. 219–228 (May 2008).     

CCD‐Δa and BV R photometry of NGC 7296

The first CCD photometric investigation of the open cluster NGC 7296 up to now was performed within the narrow band Δa photometric system, which enables us to detect peculiar objects. A deeper investigation of that cluster followed, using the standard BV R ‐Bessel filter set. The age and E (B – V ) was determined independently to log t = 8.0 ± 0.1 and 0.15 ± 0.02, respectively by using Δa and broadband photometry. In total five Be/Ae objects and two metal‐weak stars showing significant negative Δa ‐values as well as one classical chemically peculiar star could be identified within that intermediate age open cluster. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Spectroscopic Observations of the Star Formation Regions in Nearby Galaxies

In recent years the number of worldwide 8∼10 m-class ground-based telescopes is continually increased, the 4 m-diameter or smaller telescopes have become the small and medium-sized telescopes. In order to obtain some noticeable scientific results by using these existing small and medium-sized telescopes, we have to consider very carefully what we can do, and what we can not. For this reason, the Time Allocation Committee of the 2.16 m telescope of the National Astronomical observatories of China (NAOC) has decided to support some key projects since 2013. The long-term project “Spectroscopic Observations of the Star Formation Regions in Nearby Galaxies” proposed by us is one of three key projects, it is supported by the committee with 30 dark/grey nights in each of three years.     

Search for transiting exoplanets and variable stars in the open cluster NGC 7243

We report results of the first five observing campaigns for the open stellar cluster NGC 7243 in the frame of project Young Exoplanet Transit Initiative (YETI). The project focuses on the monitoring of young and nearby stellar clusters, with the aim to detect young transiting exoplanets and to study other variability phenomena on time‐scales from minutes to years. After five observing campaigns and additional observations during 2013 and 2014, a clear and repeating transit‐like signal was detected in the light curve of J221550.6+495611. Furthermore, we detected and analysed 37 new eclipsing binary stars in the studied region. The best fit parameters and light curves of all systems are given. Finally, we detected and analysed 26 new, presumably pulsating variable stars in the studied region. The follow‐up investigation of these objects, including spectroscopic measurements of the exoplanet candidate, is currently planned. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Star formation in NGC 6334 I and I(N)

The northern section of the molecular cloud complex NGC 6334 has been mapped in the CO and CS spectral line emission and in continuum emission at a wavelength of 1300 μm. Our observations highlight the two dominant sources, I and I(N), and a host of weaker sources. NGC 6334 I is associated with a cometary ultracompact H  ii region and a hot, compact core ≤10 arcsec in size. Mid-infrared and CH₃OH observations indicate that it is also associated with at least two protostellar sources, each of which may drive a molecular outflow. For region I we confirm the extreme high-velocity outflow first discovered by Bachiller & Cernicharo and find that it is very energetic with a mechanical luminosity of 390 L_⊙. A dynamical age for the outflow is ∼3000 yr. We also find a weaker outflow originating from the vicinity of NGC 6334 I. In CO and CS this outflow is quite prominent to the north-west, but much less so on the eastern side of I, where there is very little molecular gas. Spectral survey data show a molecular environment at position I which is rich in methanol, methyl formate and dimethyl ether, with lines ranging in energy up to 900 K above the ground state. NGC 6334 I(N) is more dense than I, but cooler, and has none of the high-excitation lines observed toward I. I(N) also has an associated outflow, but it is less energetic than the outflow from I. The fully sampled continuum map shows a network of filaments, voids and cores, many of which are likely to be sites of star formation. A striking feature is a narrow, linear ridge which defines the western boundary. It is unclear if there is a connection between this filament and the many potential sites of star formation, or if the filament existed prior to the star formation activity.     

Late-type X-ray Emitting Binaries in the Solar Neighborhood and in Star Forming Regions

We present a spectroscopic and photometric follow-up of binary stars, discovered in a sample of X-ray sources, aimed at a deep characterization of the stellar X-ray population in the solar neighborhood and in Star Forming Regions (SFRs). The sources have been selected from the RasTyc sample, obtained by the cross-correlation between the ROSAT all-sky survey and Tycho catalogues (Guillout et al., 1999). Thanks to the high resolution spectroscopy, we have obtained good radial velocity curves, whose solutions provided us with the mass ratios and minimum masses of the components. We have also obtained an accurate spectral classification with codes specifically developed by us. In addition, we could obtain information on the age of the sources through the Lii-6708 line and on the chromospheric activity level through the Hα line.We show also some results on very young pre-main sequence (PMS) binaries discovered as optical counterparts of X-ray sources in SFRs. The spectroscopic and photometric monitoring has allowed us to determine the orbital and physical parameters and the rotation periods, that are of great importance for testing the models of PMS evolution.     

Stochastic data in astronomy. II. Search for harmonic components of time series with very large gaps

This is an analysis of certain aspects of using the CLEAN algorithm for Fourier analysis of short segments of time series and of time series consisting of short segments of length ΔT separated by very long irregular gaps. It is assumed that the time series contain a harmonic component of amplitude A with a period longer than the length of the longest of the segments of the time series plus white noise with dispersion N². Reliability plots are constructed for determining the ranges of the parameters (ν, ϕ) for which the CLEAN procedure can be used to determine the values of ν, the frequency, and ϕ, the phase of the harmonic component, with a given accuracy. The results of this analysis are used to search for harmonic components in the variation of the Hβ line profile in spectra of the triple star δ Ori A obtained in 2004 with the BTA telescope at the Special Astrophysical Observatory of the Russian Academy of Sciences. __________ Translated from Astrofizika, Vol. 50, No. 2, pp. 281–297 (May 2007).     

Statistical results from a jcmt survey of MM and sub-MM emission in herbig ae/be stars

We have detected 1.1 mm continuum emission from 24 of 53 Herbig Ae/Be stars surveyed with the JCMT. Survival analysis shows that 1.1 mm luminosity is correlated with bolometric luminosity and with IRAS 25µm luminosity. For those stars that were also detected at 0.45 or 0.8 mm we find a typical flux dependence of the form S _#x03BD; ³, which is steeper than that of most classical T Tauri stars.     

论鲁庄公七年夏四月辛卯夜,恒星不见,夜中星陨如雨

对《春秋》记载的“鲁庄公七年(前687年)四月辛卯夜,恒星不见,夜中星陨如雨．”一段中的夜恒星何以当见而不见这个千古未解的迷团进行探讨,在1994年笔者研究的1533年狮子座流星雨出现时呈现的天空亮度的基础上,结合古今中外的有关资料, 发现这天恒星不见的原因,实际是夜中出现的流星雨产生的天空明亮掩盖恒星．文中附带证明恒星不见和星陨如雨实际是出现在同一时段,即都在夜中．同时还估算了这次流星雨的流星数密度和流星总数、掩盖恒星亮度的流星质量以及被掩盖恒星的天空面积．     

Outflow, Infall, and Rotation in High-Mass Star Forming Regions

According to theory, stars more massive than 8 M must form while still accreting material from the surrounding parental cloud: at this stage radiation pressure should reverse the infall thus preventing further growth of the stellar mass. After illustrating the two models proposed to solve this problem (accretion and coalescence), we review the observational evidence pro/contra such models, focusing on the kinematics of the molecular gas where the massive (proto)stars are embedded as the best tool to shed light on the formation mechanism. Special attention is devoted to the phenomena of infall, outflow, and rotation, concluding that the recent detection of rotating disks in massive young stellar objects is the best evidence so far in favour of the accretion model.     

High Resolution Spectroscopy of Halo Stars in the Near UV and Blue Region I. Spectra in the Wavelength Region 3550-5000 A

An atlas of high resolution (R = 60 000) CCD-spectra in the wavelength range 3500-5000A is presented for four objects in metallicity range -3.0 < [Fe/H] < -0.6, temperature range 4750 < Teff < 5900 K, and surface gravity range 1.6 < lgg < 5.0. We describe the calibration of the stellar atmospheric parameters using Alonso's formula based on the method of infrared flux and outline the determination of the abundances of a total number of 25 chemical elements. An analysis of the abundance determination errors for different chemical elements is carried out, and a method is provided for the observations and reduction of spectral material. Properties of the method of producing an atlas of spectra and line identifications are described.