Alert Notice 752: Rare Outburst of Recurrent Nova RS Ophiuchi

August 9, 2021

AAVSO Forum threads (scroll to the bottom of a thread for latest posts):
- Time Sensitive Alerts: https://www.aavso.org/outburst-rs-ophiuchi
- Novae: https://www.aavso.org/rs-ophiuchi
- Cataclysmic Variables: https://www.aavso.org/outburst-rs-ophiuchi
- Spectroscopy: https://www.aavso.org/rs-oph-outburst-2021

Please subscribe to these threads if you wish to follow this discovery. Join in the discussion or ask questions there!

Event: Outburst of recurrent nova RS Oph

Coordinates (J2000 from VSX): 17 50 13.17 -06 42 28.6  (267.55487 -6.70794)

The recurrent nova RS Oph is in outburst at a visual magnitude of 4.8, according to observations
by AAVSO observers Alexandre Amorim (AAX) of Florianopolis, Brazil, Eddy Muyllaert (MUY) of
Oostende, Belgium, and Keith Geary (GKI) of Shercock, Co. Cavan, Ireland.

Data in the AAVSO International Database show that the last outburst of RS Oph
occurred in February 2006, when the star reached visual magnitude 4.8 and was brighter than
10.5 for about 80 days; RS Oph returned to its normal inter-outburst behavior approximately
120 days after outburst maximum. Previous outbursts have been recorded in 1898, 1933, 1958,
1967, and 1985 with a probable outburst in 1945.

While the length of the interoutburst interval in RS Oph varies greatly, the shape of the
outburst and recovery to interoutburst is remarkably similar from outburst to outburst. For
a very interesting analysis of the behavior of RS Oph, see B.D. Oppenheimer and J.A. Mattei,
 JAAVSO, 22, 2, 105 (1993), or Oppenheimer and Mattei in Compact Stars in Binaries, proceedings
of IAU Symposium 165, ed. J. van Paradijs, Edward Peter Jacobus van den Heuvel, and Erik
Kuulkers, Kluwer Acad. Publ., Dordrecht, 457 (1994).

Observing recommendations: Please observe RS Oph as it continues to evolve, with observations
of all types (visual, CCD, DSLR, PEP, spectroscopy) and multiple bands as instrumentation
permits.

Observations reported to the AAVSO:
2021 Aug. 06.91000 UT, 11.1 (G. Poyner, Birmingham, UK);
07.96940, 11.2 (A. Amorim, Florianopolis, Brazil);
08.91319, 5.0 (Amorim);
08.92014, 5.1 (Muyllaert, Oostende, Belgium);
08.93056, 5.0 (K. Geary);
08.99653, 4.8 (Geary);
09.02500, 5.858 TG (G. Poyner, Birmingham, England)
09.02778, 4.9 (C. Marcos da Silva, Luminárias, Minas Gerais, Brazil)
09.04861, 4.8 (L. Cason, Kiawah Island, SC, USA)
09.05694, 4.9 (Geary);
09.05903, 4.9 (L. Shotter, Uniontown, PA, USA);
09.10764, 4.8 (L. Cason);
09.16528, 4.6 (B. Ramotowski, Tijeras, NM, USA);
09.19028, 5.1 (L. Herrington, Ketchum, OK, USA);
09.25417, 4.9 (Herrington);
09.35556, 5.0 (M. Linnolt, Naalehu, HI, USA);
09.42, 4.8: R (E. Guido, M. Rocchetto, and A. Valvasori, remotely with TEL 0.1-m f/3.6 astrograph + CCD at Heaven's Mirror Observatory, Australia and operated by Telescope Live; images saturated in 10-sec exposures);
09.44444, 4.6 (A. Pearce, Nedlands, WA, Australia);
09.54170, 4.5 (R. Stubbings, Tetoora Road, Vic., Australia);
09.63889, 4.6 (F. Romanov, Yuzhno-Morskoy (near Nakhodka), Russia);
09.66237, 4.5 (D. Benn, Klemzig, S. Australia);

More observations reported to the AAVSO can be seen using WebObs Search.

Charts: Charts with comparison stars for RS Oph may be created using the AAVSO Variable Star
Plotter (VSP)
.

Submit observations: Please submit observations using the name RS Oph.
 - Submit optical observations to the AAVSO International Database using WebObs (see below).
 - Submit spectra to the AAVSO Spectroscopy Database (AVSpec) (see below).

Links:
IAU CBET 5013: http://www.cbat.eps.harvard.edu/iau/cbet/005000/CBET005013.txt
ATel #14834: https://www.astronomerstelegram.org/?read=14834

This AAVSO Alert Notice was compiled by Sara Beck.

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Information on submitting observations to the AAVSO may be found at:
 - Photometry/visual observations: https://www.aavso.org/webobs
 - Spectroscopy: https://www.aavso.org/apps/avspec/

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