We study the line widths in the [\ion{O}{3}]$λ$5007 and H$α$ lines for two groups of planetary nebulae in the Milky Way bulge based upon spectroscopy obtained at the Observatorio Astronómico Nacional in the Sierra San Pedro Mártir (OAN-SPM) using the Manchester Echelle Spectrograph. The first sample includes objects early in their evolution, having high H$β$ luminosities, but [\ion{O}{3}]$λ5007/\mathrm Hβ< 3$. The second sample comprises objects late in their evolution, with \ion{He}{2} $λ4686/\mathrm Hβ> 0.5$. These planetary nebulae represent evolutionary phases preceeding and following those of the objects studied by Richer et al. (2008). Our sample of planetary nebulae with weak [\ion{O}{3}]$λ$5007 has a line width distribution similar to that of the expansion velocities of the envelopes of AGB stars, and shifted to systematically lower values as compared to the less evolved objects studied by Richer et al. (2008). The sample with strong \ion{He}{2} $λ4686$ has a line width distribution indistinguishable from that of the more evolved objects from Richer et al. (2008), but a distribution in angular size that is systematically larger and so they are clearly more evolved. These data and those of Richer et al. (2008) form a homogeneous sample from a single Galactic population of planetary nebulae, from the earliest evolutionary stages until the cessation of nuclear burning in the central star. They confirm the long-standing predictions of hydrodynamical models of planetary nebulae, where the kinematics of the nebular shell are driven by the evolution of the central star.
The Large sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) medium-resolution spectral survey of Galactic Nebulae (MRS-N) has conducted for three years since Sep. 2018 and observed more than 190 thousands nebular spectra and 20 thousands stellar spectra. However, there is not yet a data processing pipeline for nebular data. To significantly improve the accuracy of nebulae classification and their physical parameters, we developed the MRS-N Pipeline. This article presented in detail each data processing step of the MRS-N Pipeline, such as removing cosmic rays, merging single exposure…
Radio continuum observations trace thermal emission of ionized plasma in planetary nebulae and bring useful information on nebular geometries. A model of homogeneous sphere or shell cannot fit the nebular spectra and brightness temperatures. Two alternative models have been proposed in the literature: the first one consists of two homogeneous components, while the other one is a model of a shell with a significant radial density gradient. On the other side, prolate ellipsoidal shell model can successfully fit the surface brightness distribution of selected objects. We verify the existing model…
The Kinematics of the Permitted C II $λ$ 6578 Line in a Large Sample of Planetary Nebulae
本文介绍了76个行星状星云中83条视线的C II $λ$ 6578允许谱线的高光谱分辨率光谱观测结果,其中大部分是用位于Sierra San Pedro Mártir的国家天文台的2.1m望远镜上的Manchester Echelle摄谱仪获得的。我们研究了C Ⅱ $λ$ 6578允许谱线相对于其它允许谱线和碰撞激发谱线的运动学。统计上,我们发现,运动学的C II $λ$ 6578线是不是那些预期的,如果这条线产生的重组的C $^{2+}$离子或荧光的C $^+$离子在电离平衡中的化学均匀的星云等离子体,但相反,它的运动学是那些适合的体积比预期的更内部。这个样本中的行星状星云具有明确的形态,并且与银河系凸起中的对应物相比,H $α$线宽限制在有限的范围内(没有大的值),这两者都可以解释为年轻星云壳的结果,星云模型也支持这一推论。关于长期存在的化学丰度之间的差异推断允许和碰撞激发的发射线在光电离星云,我们的研究结果意味着,多个等离子体成分通常发生在行星状星云。
On the non-thermal kappa-distributed electrons in planetary nebulae and HII regions: the kappa index and its correlations with other nebular properties
A significant fraction of planetary nebulae (PNe) exhibit collimated outflows, distinct narrow kinematical components with notable velocity shifts with respect to the main nebular shells typically associated with low-ionization compact knots and linear or precessing jet-like features. We present here a spatio-kinematical investigation of a sample of twelve PNe with morphologies in emission lines of low-ionization species suggestive of collimated outflows. Using archival narrow-band images and our own high-dispersion long-slit echelle spectra, we confirm the presence of collimated outflows in H…
Co-spatial Long-slit UV/Optical Spectra of Ten Galactic Planetary Nebulae with HST/STIS II. Nebular Models, Central Star Properties and He+CNO Synthesis
The kinematics of the nebular shells around low mass progenitors of PNe with low metallicity
我们分析了26个行星状星云(PNe)的内部运动学与低金属丰度,似乎来自最低质量的祖星,包括晕PN人口。基于从圣佩德罗·马蒂尔PNe运动学目录(López et al. 2012)中绘制的空间分辨长缝中阶梯光栅光谱,我们根据迄今为止用于此目的的最大样本测量其全球膨胀速度来表征这些PNe的运动学。我们发现运动学,遵循在其他研究中观察到和预测的趋势,但也发现,大多数的PNe研究在这里往往有膨胀速度小于20公里/秒,在所有考虑的发射线。我们在这个具有低质量祖先的低金属丰度行星状星云样本中观察到的低膨胀速度很可能是微弱的中央星风驱动星云壳运动学的结果。这项研究补充了以前的结果(Pereyra等人,2013年,以及其中的参考文献),这些结果将PN壳的膨胀速度与中心恒星的特征联系起来。
Planetary Nebulae towards the Galactic bulge. I. [OIII] fluxes
我们给出了435个行星状星云(PN)的[OIII]λ5007通量和角直径,这些星云位于中央10' x 10'区域,朝向银河系凸起。我们的样本取自MASH PN调查的新发现以及以前已知的PN。该样本占该地区已知PN的80%。通量和直径是用Cerro-Tololo美洲天文台4米Blanco望远镜上的MOSAIC-II照相机从窄带成像中测量的。这是有史以来最大的(~60平方度),均匀的[OIII]λ5007调查银河系内部的隆起。其中104个天体已经测量了文献中的[OIII]λ5007、[OIII]λ4959、Hα或Hβ通量,我们使用这些数据进行详细的比较,以证明我们新通量的完整性。我们的独立测量结果与两个数量级以上的最佳文献来源非常一致,同时在五个数量级以上保持良好的一致性。我们的数据具有出色的分辨率和灵敏度,不仅可以获得一组稳定的均匀PN通量,还可以提供更详细的信息,以了解其复杂的,否则无法确定的[OIII]λ5007形态。这些新的,广泛的测量显着增加了可靠的[OIII]λ5007流量的银河系隆起PN使其成为一个宝贵的资源和我们的新的银河系隆起行星状星云光度函数(论文II)建设的前奏。
The Abundances of Light Neutron-Capture Elements in Planetary Nebulae III. The Impact of New Atomic Data on Nebular Selenium and Krypton Abundance Determinations
Individual distances to planetary nebulae are of the utmost relevance for our understanding of post-asymptotic giant-branch evolution because they allow a precise determination of stellar and nebular properties. Also, objects with individual distances serve as calibrators for the so-called statistical distances based on secondary nebular properties. With independently known distances, it is possible to check empirically our understanding of the formation and evolution of planetary nebulae as suggested by existing hydrodynamical simulations. We compared the expansion parallaxes that have recent…
It has recently been noted that there seems to be a strong correlation between planetary nebulae with close binary central stars, and highly enhanced recombination line abundances. We present new deep spectra of seven objects known to have close binary central stars, and find that the heavy element abundances derived from recombination lines exceed those from collisionally excited lines by factors of 5-95, placing several of these nebulae among the most extreme known abundance discrepancies. This study nearly doubles the number of nebulae known to have a binary central star and an extreme abun…
Fast highly-collimated outflows including bipolar knots, jet-like features, and point-symmetric filaments or string of knots are common in planetary nebulae (PNe). These features, generally named as jets, are thought to play an active role in the nebular shaping immediately before or at the same time that fast stellar winds and D-type ionization fronts shock and sweep up the nebular envelope. The space velocity, radial distance from the central star and kinematic age of jets in PNe cannot be determined because the inclination anglewith the line-of-sight is usually unknown. Here we have used th…
Context. Gaia Early Data Release 3 (EDR3), published in December 2020, features improved photometry and astrometry over that published in the previous DR2 file, and includes a substantially larger number of sources, of the order of 2,000 million, making it a paradigm of Big data Astronomy. Aims. We demonstrate how Gaia data mining can effectively help to solve the issue of central star misidentification, a problem that has plagued the field since its origin. As we did for DR2, our objective is to present a catalogue of CSPNe with astrometric and photometric information in EDR3. Methods. Gaia G…
Abundances of planetary nebulae and evolved stars: Iron and sulfur depletion, and carbon and nitrogen enrichment, in low- and intermediate-mass stellar populations in the Milky Way
We present narrow-band near-infrared images of a sample of 11 Galactic planetary nebulae (PNe) obtained in the molecular hydrogen (H$_{2}$) 2.122 $μ$m and Br$γ$ 2.166 $μ$m emission lines and the $K_{\rm c}$ 2.218 $μ$m continuum. These images were collected with the Wide-field InfraRed Camera (WIRCam) on the 3.6m Canada-France-Hawaii Telescope (CFHT); their unprecedented depth and wide field of view allow us to find extended nebular structures in H$_{2}$ emission in several PNe, some of these being the first detection. The nebular morphologies in H$_{2}$ emission are studied in analogy with the…
Nebular spectroscopy is a valuable tool for assessing the production of heavy elements by slow neutron(n)-capture nucleosynthesis (the s-process). Several transitions of n-capture elements have been identified in planetary nebulae (PNe) in the last few years, with the aid of sensitive high-resolution near-infrared spectrometers. Combined with optical spectroscopy, the newly discovered near-infrared lines enable more accurate abundance determinations than previously possible, and provide access to elements that had not previously been studied in PNe or their progenitors. Neutron-capture element…
The increase in discovered close binary central stars of planetary nebulae is leading to a sufficiently large sample to begin to make broader conclusions about the effect of close binary stars on common envelope evolution and planetary nebula formation. Herein I review some of the recent results and conclusions specifically relating close binary central stars to nebular shaping, common envelope evolution off the red giant branch, and the total binary fraction and double degenerate fraction of central stars. Finally, I use parameters of known binary central stars to explore the relationship bet…