We report on a detailed analysis of the optical light curve of the symbiotic system BX Mon, the data of which were gathered from the literature. The light curve covers the period December 1889 March 2009, with a gap of no observations between March 1940 and February 1972. The light curve is characterized by strong oscillations of peak to peak amplitude of 2 to more than 3 magnitudes. Before the gap the fluctuations were modulated mainly by a period Pa=1373 d, the diurnal cycle of an observer on the surface of the rotating M giant, whose sun is the hot component. After the gap the dominant periodicity is Pb=1256 d, which is the binary period of the system. Higher harmonics as well as a few beats of the two major periodicities can also be identified in the light curve. We identify one of the beat periods, Pr=656 d, as the sidereal rotation period of the giant component of the system. The period switching that took place during the gap in the observations was possibly associated with a certain cataclysmic event, hints of which may be recognized in the LC in the first 11 years after the gap. We suggest that the origin of the major oscillations is in periodic episodes of mass accretion from the M giant onto the hot component of the system. The event of the period switching is possibly related to an intensive magnetic activity in the outer layers of the giant star. [abridged]
SU Lyn is a binary system composed of a white dwarf and a red giant star. Although it is known to be bright and variable at X-ray wavelengths, the optical counterpart of the source appeared as a single red giant without prominent emission lines. Because of the lack of optical features typical for interacting systems, the system was classified as a hidden symbiotic star. We present the results of optical monitoring of the system. While SU Lyn did not show substantial photometric variability, the spectroscopic observations revealed a complex behavior. The system showed strong emission line varia…
AG Dra是一颗著名的明亮的共生双星，由一颗白矮星和一颗脉动红巨星组成。提出了长期光度监测和系统的新行为。对光度学和光谱学进行了详细的周期分析。在AG Dra系统中，检测到两个变化期。较长的一个大约550天与轨道运动有关，而较短的一个大约355天在我们的旧论文中被解释为红巨星的脉动。活动期次变化明显，但喷发周期在359 ~ 375天之间。
Discovery of variable polarization in H$α$ profile of symbiotic star Y Gem: A case for orbital-phase dependent variation of Raman-scattered Ly$β$ emission
Indian Institute of Technology Gandhinagar（印度理工学院甘地纳加尔分校）；Physical Research Laboratory（物理研究实验室）；I. Physikalisches Institut, Universit at zu Köln（科隆大学第一物理研究所）
We present new multicolour UBVRcIc photometric observations of symbiotic stars, EG And, Z And, BF Cyg, CH Cyg, CI Cyg, V1016 Cyg, V1329 Cyg, AG Dra, RS Oph, AG Peg, AX Per, and the newly discovered (August 2018) symbiotic star HBHA 1704-05, we carried out during the period from 2011.9 to 2018.75. Historical photographic and visual/V data were collected for HBHA 1704-05, FG Ser and AE Ara, AR Pav, respectively. The main aim of this paper is to present our original observations of symbiotic stars and to describe the most interesting features of their light curves. For example, periodic variation…
Exploring the long-term temporal variability in polarization through multi-epoch optical spectro-polarimetry - Part II: A sample of symbiotic and red-giant stars
Physical Research Laboratory（物理研究实验室）；Indian Institute of Technology Gandhinagar（甘地纳加尔印度理工学院）；Johns Hopkins University（约翰斯·霍普金斯大学）；NASA Goddard Space Flight Center（美国国家航空航天局戈达德航天飞行中心）
St 2-22 is a relatively poorly studied S-type symbiotic system that belongs to a small group of jet-producing systems as a result of disc accretion onto a white dwarf fed by its red giant companion. The goal of this paper is to analyse the nature and derive the basic parameters of St 2-22, and to follow the jet evolution. Photometric monitoring for over 16 yrs and high-quality spectroscopic data enabled us to shed new light on its nature. The high-resolution SALT spectra and $V I_C$ photometry obtained during and between the last two outbursts have been used to search for periodic changes, to …
Symbiotic stars often exhibit broad wings around Balmer emission lines, whose origin is still controversial. We present the high resolution spectra of the S type symbiotic stars Z Andromedae and AG Draconis obtained with the ESPaDOnS and the 3.6 m Canada France Hawaii Telescope to investigate the broad wings around H$α$ and H$β$. When H$α$ and H$β$ lines are overplotted in the Doppler space, it is noted that H$α$ profiles are overall broader than H$β$ in these two objects. Adopting a Monte Carlo approach, we consider the formation of broad wings of H$α$ and H$β$ through Raman scattering of far…
We present results of study, using observed and published spectra in optical region, of few novae (T CrB, GK Per, RS Oph, V3890 Sgr and V745 Sco) in their quiescence phase and a symbiotic star (BX Mon). Observations were made using the facilities available at 2m Himalayan Chandra Telescope (HCT). Generally, the spectra show prominent low ionization emission features of hydrogen, helium, iron and oxygen and TiO absorption features due to the cool secondary component; T CrB and GK Per show higher ionization lines. We used photoionization code CLOUDY to model these spectra. From the best-fit mode…
We present high resolution spectroscopy of the yellow symbiotic star AG Draconis with ESPaDOnS at the {\it Canada-France-Hawaii Telescope}. Our analysis is focused on the profiles of Raman scattered \ion{O}{VI} features centered at 6825 Å and 7082 Å, which are formed through Raman scattering of \ion{O}{VI}$λλ$1032 and 1038 with atomic hydrogen. These features are found to exhibit double component profiles with conspicuously enhanced red parts. Assuming that the \ion{O}{vi} emission region constitutes a part of the accretion flow around the white dwarf, Monte Carlo simulations for \ion{O}{VI} l…
Raman Scattered Ne VII$λ$973 at 4881 Å in the Symbiotic Star V1016 Cygni
本文给出了2003年和2005年利用宝贤山光学中阶梯摄谱仪获得的共生星天鹅座V1016的高分辨率光谱，从中我们发现了4881 °的宽发射特征。我们提出，这一广泛的功能是由原子氢的Ne VII $\lambda973$的拉曼散射形成的。到目前为止，原子氢的拉曼散射线的检测限于O VI $λλ$ 1032、1038和He II $λλ$ 940、972和1025。采用Ne VII $λ$ 973的中心波长973.302 nm，并考虑到$n_{air}=1.000279348$的空气折射率，确定了Ne VII拉曼散射特征的原子线中心为4880.53 nm。Ne VII $\lambda973$的线中心处的总截面计算为分支比为0.17的$2.62\times 10^{-22}{\rm\ cm^2}$。我们进行蒙特卡罗模拟来拟合Raman散射Ne VII $\lambda973$。假设Ne VII和He II发射区相对于中性散射区具有相同的运动学，我们发现4850 nm处的拉曼散射He II $λ$ 972和4881 nm处的Ne VII $λ$ 973非常好地拟合。我们还建议，氦II和氖VII发射区是固定的相对于H I区域在2003年，但他们从它后退的速度$\sim 20{\rm\ km\ s^{-1}}$在2005年。
We present and discuss the results of our photometric and spectroscopic monitoring of 2SXPS J173508.4-292958 carried out from April to August 2020. This X-ray source, in the foreground with respect to the Galactic center, brightened in X-rays during 2020, prompting our follow-up optical observations. We found the star to contain a K4III giant with a modest but highly variable Halpha emission, composed by a ~470 km/s wide component with superimposed a narrow absorption, offset by a positive velocity with respect to the giant. No orbital motion is detected for the K4III, showing an heliocentric …
Classical nova outburst has been suggested for a number of extragalactic symbiotic stars, but in none of the systems has it been proven. In this work we study the nature of one of these systems, LMC S154. We gathered archival photometric observations in order to determine the timescales and nature of variability in this system. Additionally we carried out photometric and spectroscopic monitoring of the system and fitted synthetic spectra to the observations. Carbon abundance in the photosphere of the red giant is significantly higher than that derived for the nebula, which confirms pollution o…
The H$α$ and H$β$ line profiles of the symbiotic star AG Peg observed on 1998 September (phase $ϕ$ = 10.24), display the top narrow double Gaussian and bottom broad (FWHM of 200 -- 400 kms$^{-1}$) components. The photo-ionization model indicated that the ionized zone, responsible for the hydrogen Balmer and Lyman lines, is radiation-bounded, with a hydrogen gas number density of $n_{\rm H} \sim 10^{9.85}$ cm$^{-3}$ and a gas temperature of T$_e$ = 12\,000 -- 15\,000~K. We carried out Monte Carlo simulations to fit the Raman scattering broad wings, assuming that the hydrogen Ly$β$ and Ly$γ$ lin…
How are accretion discs affected by their outflows? To address this question for white dwarfs accreting from cool giants, we performed optical, radio, X-ray, and ultraviolet observations of the outflow-driving symbiotic star MWC 560 (=V694 Mon) during its 2016 optical high state. We tracked multi-wavelength changes that signalled an abrupt increase in outflow power at the initiation of a months-long outflow fast state, just as the optical flux peaked: (1) an abrupt doubling of Balmer absorption velocities; (2) the onset of a $20$ $μ$Jy/month increase in radio flux; and (3) an order-of-magnitud…
In symbiotic binaries, jets and disk winds may be integral to the physics of accretion onto white dwarfs from cool giants. The persistent outflow from symbiotic star MWC 560 (=V694 Mon) is known to manifest as broad absorption lines (BALs), most prominently at the Balmer transitions. We report the detection of high-ionization BALs from C IV, Si IV, N V, and He II in International Ultraviolet Explorer spectra obtained on 1990 April 29-30, when an optical outburst temporarily erased the obscuring 'iron curtain' of absorption troughs from Fe II and similar ions. The C IV and Si IV BALs reached ma…
