Context. The wind mass transfer from a giant to its white dwarf companion in symbiotic binaries is not well understood. For example, the efficiency of wind mass transfer of the canonical Bondi-Hoyle accretion mechanism is too low to power the typical luminosities of the accretors. However, recent observations and modelling indicate a considerably more efficient mass transfer in symbiotic binaries.
Aims. We determine the velocity profile of the wind from the giant at the near-orbital-plane region of eclipsing S-type symbiotic binaries EG And and SY Mus, and derive the corresponding spherical equivalent of the mass-loss rate. With this approach, we indicate the high mass transfer ratio.
Methods. We achieved this aim by modelling the observed column densities taking into account ionization of the wind of the giant, whose velocity profile is derived using the inversion of Abel's integral operator for the hydrogen column density function.
Results. Our analysis revealed the spherical equivalent of the mass-loss rate from the giant to be a few times 10^{-6}M_{Sun}/yr, which is a factor of >=10 higher than rates determined by methods that do not depend on the line of sight. This discrepancy rules out the usual assumption that the wind is spherically symmetric. As our values were derived from near-orbital-plane column densities, these values can be a result of focusing the wind from the giant towards the orbital plane.
Conclusions. Our findings suggests that the wind from giants in S-type symbiotic stars is not spherically symmetric, since it is enhanced at the orbital plane and, thus, is accreted more effectively onto the hot component.
Symbiotic stars are long-period interacting binaries where the compact objects, most commonly a white dwarf, is embedded in the dense stellar wind of an evolved companion star. UV and soft X-ray emission of the accretion disk and nuclear burning white dwarf plays a major role in shaping the ionisation balance of the surrounding wind material and giving rise to the rich line emission. In this paper, we employ 2D photoionisation calculations based on Cloudy code to study the ionisation state of the circumbinary material in symbiotic systems and to predict their emission line spectra. Our simulat…
Revisiting atmospheric Roche lobe overflow in symbiotic binaries
Yunnan Observatories, Chinese Academy of Sciences (CAS)（中国科学院云南天文台）；International Centre of Supernovae (ICESUN), Yunnan Key Laboratory of Supernova Research（超新星国际中心（ICESUN），云南省超新星研究重点实验室）；University of Chinese Academy of Sciences（中国科学院大学）；Department of Physics, University of Alberta（阿尔伯塔大学物理系）；London Institute of Stellar Astrophysics（伦敦恒星天体物理学研究所）；University of Oxford, St Edmund Hall（牛津大学圣埃德蒙学堂）；Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences（波兰科学院尼古拉·哥白尼天文中心）
Searching for outbursts from Symbiotic Binaries in GOTO and ATLAS data
Armagh Observatory & Planetarium（阿马赫天文台与天文馆）；University of Warwick（华威大学）；Monash University（莫纳什大学）；University of Sheffield（谢菲尔德大学）；University of Cambridge（剑桥大学）；University College Cork（科克大学）；The Open University（开放大学）；Radboud University（拉德堡德大学）；University of Manchester（曼彻斯特大学）
Symbiotic binaries in the Gaia data. II. Symbiotic candidates from general variability classification in DR3
Charles University（查理大学）；Astronomical Institute, Faculty of Mathematics and Physics, Charles University（查理大学数学物理学院天文研究所）；Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Universidad de La Laguna（拉古纳大学）；Southern Spectroscopic Project Observatory Team (2SPOT)（南方光谱计划观测团队（2SPOT））；Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences（波兰科学院尼古拉·哥白尼天文学中心）
Context. The structure of the wind from the cool giants in symbiotic binaries carries important information for understanding the wind mass transfer to their white dwarf companions and its fuelling. Aims. In this paper, we indicate a non-spherical distribution of the neutral wind zone around the red giant (RG) in the symbiotic binary star, EG And. Methods. We achieved this aim by analysing the periodic orbital variations of fluxes and radial velocities of individual components of the H$α$ and [OIII]$λ$5007 lines observed on our high-cadence medium (R $\sim$ 11 000) and high-resolution (R $\sim…
Symbiotic stars are strongly interacting binaries, consisting of a white dwarf and a cool giant, mainly of spectral type M. AG Draconis belongs to a less numerous group of the yellow symbiotic systems, as the cool component in this binary is of a spectral type earlier than K4. Recently, after seven years of quiescence, this symbiotic star exhibited a very unusual active stage with the four minor outbursts observed. Thanks to the excellent involvement of amateur astronomers and professional observatories, we can study the activity of AG Draconis in unprecedented details. In the present work, we…
Symbiotic binaries are long period interacting binaries consisting of a white dwarf (WD) accreting material from a cool evolved giant star via stellar winds. In this paper we study the symbiotic binary LIN 358 located in the SMC. We have observed LIN 358 with the integral field spectrograph WiFeS and obtained its line emission spectrum. With the help of the plasma simulation and spectral synthesis code Cloudy, we have constructed a 2D photo-ionisation model of LIN 358. From comparison with the observations, we have determined the colour temperature of the WD in LIN 358 to be 19 eV, its bolomet…
A search for new symbiotic stars in the Milky Way: Using machine learning techniques applied to photometric databases
Universidad de La Serena（拉塞雷纳大学）；Instituto de Astronomía y Ciencias Planetarias, Universidad de Atacama（阿塔卡马大学天文与行星科学研究所）；Millennium Institute of Astrophysics (MAS)（天体物理千年研究所）；Gemini Observatory/NSF’s NOIRLab（吉米尼观测站/美国国家光学红外天文实验室）；Universidad Nacional de Hurlingham (UNAHUR)（乌尔里汉国立大学）；Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)（国家科学研究委员会）
LIN 358 and SMC N73 are two symbiotic binaries in the halo of the Small Magellanic Cloud, each composed of a hot white dwarf accreting from a cool giant companion. In this work, we characterize these systems using a combination of SED-fitting to the extant photometric data spanning a broad wavelength range (X-ray/ultraviolet to near-infrared), detailed analysis of the APOGEE spectra for the giant stars, and orbit fitting to high quality radial velocities from the APOGEE database. Using the calculated Roche lobe radius for the giant component and the mass ratio for each system, it is found that…
Various white-dwarf (WD) binary scenarios have been proposed trying to understand the nature and the diversity of Type Ia supernovae (SNe Ia). In this work, we study the evolution of carbon-oxygen WD -- red giant (RG) binaries (including the role of magnetic confinement) as possible SN Ia progenitors (the so-called symbiotic progenitor channel). Using the \textsc{mesa} stellar evolution code, we calculate the time dependence of the structure of the RG star, the wind mass loss, the Roche-lobe-overflow (RLOF) mass-transfer rate, the polar mass-accretion rate (in the case of magnetic confinement)…
CHARA Array Observations of the Evolved Components in Symbiotic Star Systems
The Pennsylvania State University（宾夕法尼亚州立大学）；New Mexico Institute of Mining and Technology（新墨西哥矿业理工学院）；Adam Mickiewicz University（亚当·密茨凯维奇大学）；University of Michigan（密歇根大学）
The spectroscopic evolution of the symbiotic star AG Draconis. I.The O VI Raman, Balmer, and helium emission line variations during the outburst of 2006-2008
AG Dra是一小群低金属量的S-型共生双星之一，它们与K-型巨星共生，偶尔会发生不明原因的短期爆发。我们的目的是利用红巨星风中的光学拉曼谱线和其他辐射特征来研究白矮星在爆发过程中的行为。我们的目标是确定在一个重大的爆发事件，并研究在一个重大的爆发过程中的紫外线和光学之间的耦合在这个系统中的增益的包络线和风的变化。利用中、高分辨率的地基光谱，并与档案资料中的$FUSE$和$HST/STIS$光谱进行对比，研究了2006年9月以来爆发期间OVI特征和Balmer、He I、He II谱线的演化。到2007年5月，并包括最近的观测（2009年），以研究源的后续演变。的O VI拉曼功能完全消失在高峰期的主要爆发和随后的变化与前十年的报告有很大不同。He I和He II线以及巴耳末线的相位随拉曼特征而变化，但在2006-2008年期间，He I 6678，7065相对于O VI拉曼6825的变化存在双重值，这在以前没有报道过。通过爆发间隔的拉曼特征比的变化是一致的O VI FUV共振风线从白矮星和周围的O $^{+5}$电离区域内的红巨星风引起的膨胀和冷却的白矮星光球的消失。
