Spectroscopic orbits for symbiotic stars. I - The recurrent nova T Coronae Borealis

A high resolution spectroscopy survey of symbiotic stars is conducted in the southern hemisphere by the authors, using the Coudé Echelle Spectrograph (CES), equipped with a CCD at the ESO Coudé Auxiliary Telescope (CAT), and concurrently in the northern hemisphere by Bode, Evans, Meaburn and collaborators, using the UK facilities at La Palma. So far, more than 400 spectra of about 70 stars have been obtained, mostly during 1988 and 1989. The southern part of the work will be described below.The discussion of symbiotic stars in the context of novae is not far-fetched. A number of symbiotics are known to have nova-like outbursts, and several novae are not easily distinguished from symbiotic stars. A noteworthy example is the most recently recognized recurrent nova, V745 Sco, first observed by Liller on July 24, 1989. It is described here, both because in late decline it represents a link between novae and symbiotic stars, and because of its current interest.

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A search for the modern counterparts of the Far Eastern guest stars 369 CE, 386 CE and 393 CE

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1970 ◽

2020 ◽

Vol 497 (2) ◽

pp. 1419-1433 ◽

Cited By ~ 1

Author(s):

Susanne M Hoffmann ◽

Nikolaus Vogt

Keyword(s):

Case Studies ◽

Cataclysmic Variables ◽

Fourth Century ◽

Symbiotic Stars ◽

Historical Texts ◽

Naked Eye ◽

Recurrent Nova ◽

Nova Shell ◽

Far Eastern ◽

The Given

ABSTRACT In this study, we apply our previously developed method to investigate ancient transient sightings in order to derive consequences for modern astrophysical problems. We present case studies of three observations of so-called guest stars in the fourth century CE, which lasted several months each. These three observations had been discussed and suggested as possible supernovae, but slow novae are also viable alternatives. Our careful re-interpretation of the historical texts and the currently known objects in the given fields shed new light on this topic. In particular, for the two events in 386 and 393 CE we suggest possible supernova identifications, while in all three cases there are interesting candidates for past classical or recurrent nova eruptions among known cataclysmic variables (CVs) and/or symbiotic stars. We suggest that the transient of 369 can be explained as a classical and possibly recurrent nova instead of a supernova. The most plausible candidates are BZ Cam, a CV with a possible nova shell, or CQ Dra, a naked-eye multiple system perhaps able to permit an overwhelmingly bright nova with day-time visibility.

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LMC S154: the first Magellanic symbiotic recurrent nova

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834165 ◽

2019 ◽

Vol 624 ◽

pp. A133

Author(s):

Krystian Iłkiewicz ◽

Joanna Mikołajewska ◽

Brent Miszalski ◽

Mariusz Gromadzki ◽

Berto Monard ◽

...

Keyword(s):

Recurrence Time ◽

Symbiotic Stars ◽

Spectroscopic Monitoring ◽

System A ◽

Photometric Observations ◽

Rare Class ◽

Bona Fide ◽

Recurrent Nova ◽

Red Giant ◽

Nova Outburst

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 of the circumbinary material by the ejecta from nova outburst. The photometric and spectroscopic data show that the system reached quiescence in 2009, which means that for the first time all of the phases of a nova outburst were observed in an extragalactic symbiotic star. The data indicate that most probably there were three outbursts observed in LMC S154, which would make this system a member of a rare class of symbiotic recurrent novae. The recurrent nature of the system is supported by the discovery of coronal lines in the spectra, which are observed only in symbiotic stars with massive white dwarfs and with short-recurrence-time outbursts. Gathered evidence is sufficient to classify LMC S154 as the first bona fide extragalactic symbiotic nova, which is likely a recurrent nova. It is also the first nova with a carbon-rich donor.

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Symbiotic Stars at Optical, Infrared and Radio Wavelengths

International Astronomical Union Colloquium ◽

10.1017/s025292110007336x ◽

1979 ◽

Vol 46 ◽

pp. 125-149 ◽

Cited By ~ 3

Author(s):

David A. Allen

Keyword(s):

Temperature Regime ◽

Type Star ◽

Stellar Systems ◽

Symbiotic Stars ◽

Lower Excitation ◽

Definition Of ◽

Original Type

No paper of this nature should begin without a definition of symbiotic stars. It was Paul Merrill who, borrowing on his botanical background, coined the termsymbioticto describe apparently single stellar systems which combine the TiO absorption of M giants (temperature regime ≲ 3500 K) with He II emission (temperature regime ≳ 100,000 K). He and Milton Humason had in 1932 first drawn attention to three such stars: AX Per, CI Cyg and RW Hya. At the conclusion of the Mount Wilson Ha emission survey nearly a dozen had been identified, and Z And had become their type star. The numbers slowly grew, as much because the definition widened to include lower-excitation specimens as because new examples of the original type were found. In 1970 Wackerling listed 30; this was the last compendium of symbiotic stars published.

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The Shell of the Recurrent Nova T Pyxidis: A Model Based on Shocks

The Astrophysical Journal ◽

10.1086/303555 ◽

1997 ◽

Vol 475 (2) ◽

pp. 803-811 ◽

Cited By ~ 28

Author(s):

Marcella Contini ◽

Dina Prialnik

Keyword(s):

Model Based ◽

Recurrent Nova

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Discovery of five new Galactic symbiotic stars in the VPHAS+ survey

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab195 ◽

2021 ◽

Vol 502 (2) ◽

pp. 2513-2517

Author(s):

Stavros Akras ◽

Denise R Gonçalves ◽

Alvaro Alvarez-Candal ◽

Claudio B Pereira

Keyword(s):

Spectroscopic Data ◽

Selection Criterion ◽

Optical Spectra ◽

Emission Lines ◽

High Rate ◽

Symbiotic Stars ◽

Selection Of

ABSTRACT We report the validation of a recently proposed infrared (IR) selection criterion for symbiotic stars (SySts). Spectroscopic data were obtained for seven candidates, selected from the SySt candidates of Akras et al. by employing the new supplementary IR selection criterion for SySts in the VST/OmegaCAM Photometric H-Alpha Survey. 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 to their IR colours and optical spectra, all five newly discovered SySts are classified as S-type. The high rate of true SySts detections of this work demonstrates that the combination of the H α emission and the new IR criterion improves the selection of target lists for follow-up observations by minimizing the number of contaminants and optimizing the observing time.

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