Symbiotic Stars in the APOGEE Survey: The Case of LIN 358 and SMC N73 (LIN 445a)
Jasmin E. Washington, Hannah M. Lewis, Borja Anguiano, Steven R. Majewski, S. Drew Chojnowski, Verne V. Smith, Keivan G. Stassun, Carlos Allende Prieto, Katia C… 展开作者
Jasmin E. Washington, Hannah M. Lewis, Borja Anguiano, Steven R. Majewski, S. Drew Chojnowski, Verne V. Smith, Keivan G. Stassun, Carlos Allende Prieto, Katia Cunha, David L. Nidever, D. A. Garcia-Hernandez, Kaike Pan
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 LIN 358 is likely undergoing mass transfer via wind Roche lobe overflow while the accretion mechanism for SMC N73 remains uncertain. This work presents the first orbital characterization for both of these systems (yielding periods of >270 and >980 days, respectively, for SMC N73 and LIN 358) and the first global SED fitting for SMC N73. In addition, variability was identified in APOGEE spectra of LIN 358 spanning 17 epochs over two years that may point to a time variable accretion rate as the product of an eccentric orbit.
Draco C1 is a known symbiotic binary star system composed of a carbon red giant and a hot, compact companion -- likely a white dwarf -- belonging to the Draco dwarf spheroidal galaxy. From near-infrared spectroscopic observations taken by the Apache Point Observatory Galactic Evolution Experiment (APOGEE-2), part of Sloan Digital Sky Survey IV, we provide updated stellar parameters for the cool, giant component, and constrain the temperature and mass of the hot, compact companion. Prior measurements of the periodicity of the system, based on only a few epochs of radial velocity data or relativ…
I present here the first results from an ongoing pilot project with the 1.6 m telescope at the OPD, Brasil, aimed at the detection of the OVI $λ$6830 line via linear polarization in symbiotic stars. The main goal is to demonstrate that OVI imaging polarimetry is an efficient technique for discovering new symbiotic stars. The OVI $λ$6830 line is found in 5 out of 9 known symbiotic stars, in which the OVI line has already been spectroscopically confirmed, with at least 3-$σ$ detection. Three new symbiotic star candidates have also been found.
SU Lyn, a star that ostensibly appears to be an unremarkable late M type giant, has recently been proposed to be a symbiotic star largely based on its hard X-ray properties. The star does not display, in low-resolution optical spectra, the high excitation lines typically seen in the spectra of symbiotic stars. In the present work, UV, optical, and near-infrared observations are presented, aimed at exploring and strengthening the proposed symbiotic classification for this star. Our Far-UV 1300-1800$Å$ spectrum of SU Lyn, obtained with the ASTROSAT mission's UVIT payload, shows emission lines of…
Yellow symbiotic stars are useful targets to probe whether mass transfer has happened in these binary systems. However, the number of known yellow symbiotic stars is very scarce. We report spectroscopic observations of five candidate yellow symbiotic stars selected by their position in the 2MASS (J-H) vs. (H-Ks) diagram and included in some emission-line catalogs. Among the five candidates, only StHa63 is identified as a new yellow symbiotic star because of its spectrum and its position in the [TiO]1-[TiO]2 diagram that indicates a K4-K6 spectral type. In addition, the derived electron density…
We introduce the first results from an ongoing, systematic survey for new symbiotic stars selected from the AAO/UKST SuperCOSMOS H$α$ Survey (SHS). The survey aims to identify and characterise the fainter population of symbiotic stars underrepresented in extant catalogues. The accreting white dwarfs (WDs) in symbiotic stars, fuelled by their red giant donors with high mass loss rate winds, make them promising candidates for type Ia supernovae. Several candidates were observed spectroscopically with the Southern African Large Telescope (SALT). A total of 12 bona-fide and 3 possible symbiotic st…
We report on the discovery of a new Small Magellanic Cloud (SMC) symbiotic star, OGLE-SMC-LPV-00861, previously catalogued as H$α$ emission line source LIN 9. The OGLE light curve shows multiple-maxima outburst behaviour over $\sim$1200 d with a maximum outburst of $ΔV=1.5$ mag. An optical spectrum of LIN 9 taken with the Southern African Large Telescope (SALT) at quiescence reveals a K5 red giant with emission lines confirming its symbiotic star nature, demonstrating the potential use of ongoing large time-domain surveys to identify strong symbiotic star candidates. It is the first Magellanic…
In this paper we discuss the photometric and spectroscopic observations of newly discovered (symbiotic) systems in the dwarf spheroidal galaxy NGC 205. The Gemini Multi-Object Spectrograph on-off band [O III] 5007 A emission imaging highlighted several [O III] line emitters, for which optical spectra were then obtained (Gonçalves et al. 2014). The detailed study of the spectra of three objects allow us to identify them as true, likely and possible symbiotic systems (SySts), the first ones discovered in this galaxy. SySt-1 is unambiguously classified as a symbiotic star, because of the presence…
We report on magnetic field measurements of 157 chemically peculiar A/B stars (Ap/Bp) based on resolved, magnetically split absorption lines present in $H$-band spectra provided by the Sloan Digital Sky Survey (SDSS)/Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. These stars represent the extreme magnetic end of a still-growing sample of >900 Ap/Bp stars selected among the APOGEE telluric standard stars as those with Ce III absorption lines and/or literature Ap/Bp classifications. The lines most frequently resolved into their split components for these stars in the $H$…
We present an analysis of high resolution spectral observations of the symbiotic star StHa 190. A 30 days period has been derived from radial velocities of the G-type absorption lines and the HeII 4686A emission line. The main aim of this work was to look for explanation of the very wide absorption lines of the yellow giant. The very low mass function obtained from the absorption lines radial velocities suggests that the observed changes probably do not corespond to the orbital motion of this star.
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…
The symbiotic star AG Dra experienced a double-peaked outburst of 0.6 magnitudes in April and May 2016. Photometry and spectroscopy through the outburst showed the B-V colour index varying linearly with the V magnitude and enabled the temperature variation of the hot star to be calculated from the changing flux in the H beta and He II 4686A emission lines.
We report on $H$-band spectra of chemically peculiar Mercury-Manganese (HgMn) stars obtained via the SDSS/APOGEE survey. As opposed to other varieties of chemically peculiar stars such as classical Ap/Bp stars, HgMn stars lack strong magnetic fields and are defined by extreme overabundances of Mn, Hg, and other heavy elements. A satisfactory explanation for the abundance patterns remains to be determined, but low rotational velocity is a requirement and involvement in binary/multiple systems may be as well. The APOGEE HgMn sample currently consists of 269 stars that were identified among the t…
The scientific community's interest on the stellar parameters of M dwarfs has been increasing over the last few years, with potential applications ranging from galactic characterization to exoplanet detection. The main motivation for this work is to develop an alternative and objective method to derive stellar parameters for M dwarfs using the H-band spectra provided by the Apache Point Observatory Galactic Evolution Experiment (APOGEE). Synthetic spectra generated with \textit{iSpec}, \textit{Turbospectrum}, \textit{MARCS} models atmospheres and a custom made line list including over 1 000 00…
Symbiotic stars are interacting binaries in which the first-formed white dwarf accretes and burns material from a red giant companion. This paper aims at presenting physical characteristics of these objects and discussing their possible link with progenitors of type Ia supernovae.
We report the discovery of a possible symbiotic star, in the Large Magellanic Cloud (LMC). The object under consideration here, designated as RP 870, was detected during the course of a comprehensive H$α$ survey of the LMC by Reid & Parker (2012). The spectrum of RP 870 showed high ionization emission lines of He I, He II and [O III] and molecular absorption bands of TiO $λ$$λ$6180, 7100. The collective signatures of a hot component (high excitation/ionization lines) and of a cool component (TiO molecular bands) are seen in RP 870, from which we propose it as a symbiotic star. Since known symb…
We analyze high dispersion emission lines of the symbiotic nova AG Peg, observed in 1998, 2001, and 2002. The H$α$ and H$β$ lines show three components, two narrow and one underlying broad line components, but most other lines, such as HI, HeI, and HeII lines, show two blue- and red-shifted components only. A recent study by Lee & Hyung (2018) suggested that the double Gaussian lines emitted from a bipolar conic shell is likely to form Raman scattering lines observed in 1998. In this study, we show that the bipolar cone with an opening angle of 74$^{o}$, which expands at a velocity of 70 kms$^…
Variations of the emission lines in the spectrum of the yellow symbiotic star AG Dra have been studied for over 14 years (1997 - 2011), using more than 500 spectra obtained on the 1.5-metre telescope at Tartu Observatory, Estonia. The time interval covered includes the major (cool) outburst of AG Dra that started in 2006. Main findings can be summarized as follows: (i) cool and hot outbursts of AG Dra can be distinguished from the variations of optical emission lines; (ii) the Raman scattered emission line of O VI at $λ\,6825$ almost disappeared during the cool outburst; (iii) lower excitation…
In the optical, the spectrum of symbiotic binaries consists of contributions from the cool giant, symbiotic nebula and the hot star. Strong emission lines are superposed on the continuum. In this paper we introduce a simple method to extract individual components of radiation from photometric UBV magnitudes. We applied the method to classical symbiotic stars AX Per, AG Dra, AG Peg and Z And, the symbiotic novae RR Tel and V1016 Cyg and the classical nova V1974 Cyg during its nebular phase. We estimated the electron temperature and emission measure of the nebula in these systems and the V magni…
A goal of the IPHAS survey is to determine the frequency and nature of emission-line sources in the Galactic plane. According to our selection criteria, K 3-22 is a candidate symbiotic star, but it was previously classified as a planetary nebula. To determine its nature, we acquired a low-resolution optical spectrum of K 3-22. Our analysis of our spectroscopy demonstrates that K 3-22 is indeed a D-type symbiotic star, because of its high excitation nebular spectrum and the simultaneous presence of Raman-scattered O VI emission at 6825 and 7082 angstrom, which is detected primarily in symbiotic…
Results of the study of the symbiotic binary Z And during its recent active phase 2000 -- 2010 when it experienced a series of six optical outbursts are presented. High-resolution spectra obtained during the first and fourth outburst, which was the strongest one, have been analyzed. These data are compared with results of theoretical computations. The comparison provides information about the behaviour of the system during the entire active phase rather than during an individual outburst. In particular it was found fundamental difference between the first outburst, which opened the active phas…
Very young (t $\lesssim$ 10 Myrs) stars possess strong magnetic fields that channel ionized gas from the interiors of their circumstellar discs to the surface of the star. Upon impacting the stellar surface, the shocked gas recombines and emits hydrogen spectral lines. To characterize the density and temperature of the gas within these accretion streams, we measure equivalent widths of Brackett (Br) 11-20 emission lines detected in 1101 APOGEE spectra of 326 likely pre-main sequence accretors. For sources with multiple observations, we measure median epoch-to-epoch line strength variations of …
Symbiotic stars are the longest orbital period interacting binaries, where nova-like outbursts are generated by the accretion of a high mass loss rate red giant wind onto a white dwarf companion. Long-term photometric monitoring surveys such as OGLE and MACHO are ideal platforms to identify nova-like events in symbiotic stars, however there are only a handful of known systems within the small footprint of these surveys. We introduce a systematic Halpha emission line object survey for new symbiotic stars covering 35 deg^2 towards the Galactic Bulge that combines deep 2dF/AAOmega spectroscopy wi…
APOGEE has amassed the largest ever collection of multi-epoch, high-resolution (R~22,500), H-band spectra for B-type emission line (Be) stars. The 128/238 APOGEE Be stars for which emission had never previously been reported serve to increase the total number of known Be stars by ~6%. We focus on identification of the H-band lines and analysis of the emission peak velocity separations (v_p) and emission peak intensity ratios (V/R) of the usually double-peaked H I and non-hydrogen emission lines. H I Br11 emission is found to preferentially form in the circumstellar disks at an average distance…
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…
In this work, we present the discovery and characterization of a new southern S-type symbiotic star, DeGaPe 35. We have obtained the low-resolution spectroscopic observations and supplemented them with photometry from Gaia DR3 and other surveys. The optical spectra of this target show prominent emission lines, including highly ionized [Fe VII] and O VI lines. The cool component of this symbiotic binary is an M4-5 giant with effective temperature ~ 3 380 - 3 470 K and luminosity ~ 3 000 L$_\odot$ (for the adopted distance of 3 kpc). The hot component is a shell-burning white dwarf. The photomet…
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…
APOGEE spectra offer $\lesssim$1 km s$^{-1}$ precision in the measurement of stellar radial velocities (RVs). This holds even when multiple stars are captured in the same spectrum, as happens most commonly with double-lined spectroscopic binaries (SB2s), although random line of sight alignments of unrelated stars can also occur. We develop a code that autonomously identifies SB2s and higher order multiples in the APOGEE spectra, resulting in 7273 candidate SB2s, 813 SB3s, and 19 SB4s. We estimate the mass ratios of binaries, and for a subset of these systems with sufficient number of measureme…
Line profiles containing indication of bipolar collimated outflow along with P Cyg absorption during phase of activity of several symbiotic systems are considered. The Hgamma profile of Z And during its 2006 outburst consisted of four groups of components. The profile of the HeI λ 5876 line of the Hen 3-1341 system during its 1998-2004 outburst had high-velocity satellite components on one hand and a broad P Cyg absorption on other hand. The Halpha and Hbeta profiles of the BF Cyg system during its 2006-2012 outburst had satellite components, observed for the first time, along with P Cyg absor…
We aimed to verify the nature and derive the basic parameters of the symbiotic star candidate [JD2002] 11. For this purpose, we obtained and analysed an X-Shooter spectrum of [JD2002] 11. We also used optical and infrared photometry available for the object. Emission-line diagnostic ratios are characteristic of a dusty type symbiotic star and reveal a two-component nebula (low- and high-density). The spectral energy distribution is well fitted with a two-component blackbody spectrum with the respective temperatures of 1150 K and 600 K. The total luminosity of $\rm 3000\,L_{\odot}$ is consisten…
LT Del is a yellow symbiotic system that consists of a bright K3-type giant and a hot subdwarf with a temperature of about 10$^5$ K. We present the results of our spectroscopic observations of LT Del over the period 2010-2018. In 2017 the star experienced a second low-amplitude ($ΔV\sim0.^{m}7$) outburst in the history of its studies. The emission spectrum of the star represented in the optical range by hydrogen, neutral and ionized helium lines underwent significant changes in the outburst. The fluxes in the HI and HeI emission lines increased by a factor of 5-6, the HeII $λ$4686 line grew by…
We explore the synergy between photometric and spectroscopic surveys by searching for periodic variable stars among the targets observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) using photometry from the All-Sky Automated Survey for Supernovae (ASAS-SN). We identified 1924 periodic variables among more than 258000 APOGEE targets; 465 are new discoveries. We homogeneously classified 430 eclipsing and ellipsoidal binaries, 139 classical pulsators (Cepheids, RR Lyrae and delta Scuti), 719 long period variables (pulsating red giants) and 636 rotational variables. The …
We present photometric and spectral observations of the symbiotic star ZZ CMi. We detect intranight variability - flickering and smooth variations in U band. The amplitude of the flickering is about 0.10-0.20 mag in U band. In the B band the variability is lower, with amplitude less than 0.03 mag. We also detect variability in the H-alpha and H-beta emission lines, and find an indication for outflow with velocity of about 120-150 km/s. The results indicate that ZZ CMi is an accretion powered symbiotic containing an M4-M6 III cool component with an white dwarf resembling recurrent novae and jet…
We are performing a search for symbiotic stars using IPHAS, the INT Halpha survey of the northern Galactic plane, and follow-up observations. Candidate symbiotic stars are selected on the basis of their IPHAS and near-IR colours, and spectroscopy and photometry are obtained to determine their nature. We present here observations of the symbiotic star candidate IPHAS J205836.43+503307.2. The optical spectrum shows the combination of a number of emission lines, among which are the high-excitation species of [OIII], HeII, [Ca V], and [Fe VII], and a red continuum with the features of a star at th…
We report the discovery and characterization of a new symbiotic star of the accreting-only variety, which we observed in the optical/near-infrared (NIR) with VLT/X-Shooter and in the X-rays/ultraviolet with Swift/UVOT+XRT. The new symbiotic star, THA 15-31, was previously described as a pre-main sequence star belonging to the Lupus~3 association. Our observations, ancillary data, and Gaia EDR3 parallax indicate that THA 15-31 is a symbiotic star composed of an M6III red giant and an accreting companion, is subject to E(B-V)=0.38 reddening, and is located at a distance of ~12 kpc and at 1.8 kpc…
The symbiotic binary AG Dra regularly undergoes quiescent and active stages which consist of several outbursts repeating with about 360d interval. The recent outburst activity of AG Dra started by the minor outburst in the late spring of 2015 and was definitely confirmed by the outbursts in April 2016 and May 2017. In the presented work, the photometric and spectroscopic behaviour of the recent outburst activity of AG Dra is presented in detail. Moreover, the temperature of the white dwarf in AG Dra is studied based on the behaviour of the prominent emission lines. We show that a disentangleme…
We report the validation of a recently proposed infrared selection criterion for symbiotic stars (SySts). Spectroscopic data were obtained for seven candidates, selected from the SySt candidates of Akras et al. (2019, MNRAS, 483, 5077) by employing the new supplementary infrared selection criterion for SySts in the VST/OmegaCAM Photometric H-Alpha Survey (VPHAS+). Five of them turned out to be genuine SySts after the detection of H$α$, He II and [O III] emission lines as well as TiO molecular bands. The characteristic O VI Raman-scattered line is also detected in one of these SySts. According …
NSV 11749 is a little-studied variable star, discovered by W. J. Luyten, which had a long-duration outburst around the year 1903, reaching blue magnitude 12.5 at maximum. Following the outburst, it has apparently been quiescent at about blue magnitude 17 for the past century. It was recently suggested that NSV 11749 may have been a low- or intermediate-mass star that underwent a final helium shell flash, making it temporarily a "born-again" red giant. If so, it would be only the fourth known member of this class, along with V605 Aql, FG Sge, and V4334 Sgr. However, our newly obtained optical a…
The H$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…
We have initiated a survey aimed at locating a nearly complete sample of classical symbiotic stars (SySt) in the Magellanic Clouds. Such a sample is nearly impossible to obtain in the Milky Way, and is essential to constrain the formation, evolution and demise of these strongly interacting, evolved binary stars. We have imaged both Clouds in Halpha and He II 4686 narrow-band filters deeply enough to detect all known symbiotic stars. While He II 4686 is not present in all SySt, our method should yield a high success rate because the mimics of SySt are not as likely as true symbiotics to show th…
There have been several surprising developments in our understanding of symbiotic binary stars and nova eruptions over the last decade or so based on multiwavelength data. For example, symbiotic stars without shell burning on their white dwarfs have been revealed through their X-ray emission, UV excess, and UV variability. These purely accretion powered symbiotic stars have much weaker optical emission lines than those with shell burning, and are therefore harder to discover. Yet they may be as numerous as symbiotic stars with shell burning. Interestingly, both types of symbiotic stars are cap…
Symbiotic stars are long-orbital-period interacting-binaries characterized by extended emission over the whole electromagnetic range and by complex photometric and spectroscopic variability. In this paper, the first of a series, we present OGLE light curves of all the confirmed symbiotic stars in the Large Magellanic Cloud, with one exception. By careful visual inspection and combined time-series analysis techniques, we investigate for the first time in a systematic way the photometric properties of these astrophysical objects, trying in particular to distinguish the nature of the cool compone…
We monitored a set of emission lines in the optical spectra of CH Cyg using the 1.5-m telescope at the Tartu Observatory, Estonia. Most of the spectra were registered in the H alpha region, but other Balmer lines and lines of He, N, O, and Fe were also investigated in terms of their equivalent widths, radial velocities, and absolute fluxes. The spectra indicate different stages that CH Cyg has been through in the course of our observations. During quiescence, the strength of the line profiles changes in opposite phase with the star's luminosity. The H alpha profile becomes double-peaked at tim…
High-resolution H-band spectra of five bright field K, M, and MS giants, obtained from the archives of the Kitt Peak National Observatory (KPNO) Fourier Transform Spectrometer (FTS), are analyzed to determine chemical abundances of 16 elements. The abundances were derived via spectrum synthesis using the detailed linelist prepared for the SDSS III Apache Point Galactic Evolution Experiment (APOGEE), which is a high-resolution near-infrared spectroscopic survey to derive detailed chemical abundance distributions and precise radial velocities for 100,000 red giants sampling all Galactic stellar …
Pre-outburst 2MASS and WISE photometry of Nova Sco 2014 (V1534 Sco) have suggested the presence of a cool giant at the location of the nova in the sky. The spectral evolution recorded for the nova did not however support a direct partnership because no flash-ionized wind and no deceleration of the ejecta were observed, contrary to the behavior displayed by other novae which erupted within symbiotic binaries like V407 Cyg or RS Oph. We have therefore obtained an 0.8-2.5 micron spectra of the remnant of Nova Sco 2014 in order to ascertain if a cool giant is indeed present and if it is physically…
Accurate BVRI optical photometry of StHa 169 has been collected during the period 2005-2016. It reveals two outbursts, in 2009 and 2016, both peaking at B=13.6. The mean brightness in quiescence was B=15.29. In response to the 2016 outburst, the integrated absolute flux of the emission lines increased by a factor of 7 for Balmer, 9 for HeI lines, and 4.5 for HeII 4686, the Balmer continuum turned into strong emission, and [NeV] 3526 and OVI Raman 6825 Ang emissions disappeared. We have reconstructed the 1897-1951 B-band lightcurve of StHa 169 from Harvard historical plates. On top of a slow de…
We present a new census of Galactic and extragalactic symbiotic stars (SySts). This compilation contains 323 known and 87 candidate SySts. Of the confirmed SySts, 257 are Galactic and 66 extragalactic. The spectral energy distributions (SEDs) of 348 sources have been constructed using 2MASS and AllWISE data. Regarding the Galactic SySts, 74% are S-types, 13% D and 3.5% D$^{\prime}$. S-types show an SED peak between 0.8 and 1.7 $μ$m, whereas D-type show a peak at longer wavelengths between 2 and 4 $μ$m. D$^{\prime}$-type, on the other hand, display a nearly flat profile. Gaia distances and effe…
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has observed the H-band spectra of over 200 000 stars with $R\sim22 000$. The main motivation for this work is to test an alternative method to the standard APOGEE pipeline (APOGEE Stellar Parameter and Chemical Abundances Pipeline, ASPCAP) to derive parameters in the Near-InfraRed (NIR) for FGK dwarfs. \textit{iSpec} and \textit{Turbospectrum} are used to generate synthetic spectra matching APOGEE observations and to determine the parameters through $χ^2$ minimization. We present spectroscopic parameters ($T_\mathrm{eff}$, $[…
Symbiotic star surveys have traditionally relied almost exclusively on low resolution optical spectroscopy. However, we can obtain a more reliable estimate of their total Galactic population by using all available signatures of the symbiotic phenomenon. Here we report the discovery of a hard X-ray source, 4PBC J0642.9+5528, in the Swift hard X-ray all-sky survey, and identify it with a poorly studied red giant, SU Lyn, using pointed Swift observations and ground-based optical spectroscopy. The X-ray spectrum, the optical to UV spectrum, and the rapid UV variability of SU Lyn are all consistent…
We have performed mm-wave observations with the IRAM 30m telescope of the 12CO J=2-1 and J=1-0, 13CO J=2-1 and J=1-0, and SiO J=5-4 transitions in the symbiotic stars R Aqr, CH Cyg, and HM Sge. The data were analyzed by means of a simple analytical description of the general properties of molecular emission from the inner shells around the cool star. Numerical calculations of the expected line profiles, taking into account the level population and radiative transfer under such conditions, were also performed. Weak emission of 12CO J=2-1 and J=1-0 was detected in R Aqr and CH Cyg; a good line p…
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 eq…
Context. The APOGEE survey has obtained high-resolution infrared spectra of more than 100,000 stars. Deriving chemical abundances patterns of these stars is paramount to piecing together the structure of the Milky Way. While the derived chemical abundances have been shown to be precise for most stars, some calibration problems have been reported, in particular for more metal- poor stars. Aims. In this paper, we aim to (1) re-determine the chemical abundances of the APOGEE+Kepler stellar sample (APOKASC) with an independent procedure, line list and line selection, and high quality surface gravi…
AG Dra is one of a small group of low metallicity S-type symbiotic binaries with K-type giants that undergoes occasional short-term outbursts of unknown origin. Our aim is to study the behavior of the white dwarf during an outburst using the optical Raman lines and other emission features in the red giant wind. The goal is to determine changes in the envelope and the wind of the gainer in this system during a major outburst event and to study the coupling between the UV and optical during a major outburst. Using medium and high resolution groundbased optical spectra and comparisons with archiv…
We present a new updated catalogue of Galactic and extragalactic symbiotic stars (SySts). Since the last catalogue of SySts (Belczynski et al. 2000), the number of known SySts has significantly increased. Our new catalogue contains 316 known and 82 candidates SySts. Of the confirmed Systs 252 are located in our Galaxy and 64 in nearby galaxies. This reflects an increase of $\sim$50% in the population of Galactic SySts and $\sim$400% in the population of extragalactic SySts. The spectral energy distribution (SED) of 334 (known and candidates) SySts have been constructed using the 2MASS and WISE…
Analysis of the Gaia DR3 planetary nebula candidates and the possible symbiotic stars among them
Southern Spectroscopic Project Observatory Team (2SPOT)（南方光谱项目观测团队（2SPOT））；Astronomical Institute of Charles University（查理大学天文研究所）；Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）
We present a semi-empirical spectral classification scheme for normal B-type stars using near-infrared spectra (1.5-1.7 $μ$m) from the SDSS APOGEE2-N DR14 database. The main motivation for working with B-type stars is their importance in the evolution of young stellar clusters, however we also take advantage of having a numerous sample (316 stars) of B-type star candidates in APOGEE2-N, for which we also have optical (3600-9100 \angstrom) counterparts from the LAMOST survey. By first obtaining an accurate spectral classification of the sources using the LAMOST DR3 spectra and the canonical spe…
