RS Ophiuchi

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RS Ophiuchi A / B
Recurrent nova RS Ophiuchi as seen 23 FEB 2006 from Mt Laguna, Calif.jpg
Recurrent nova RS Ophiuchus in eruption of February 2006
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ophiuchus
Right ascension 17h 50m 13.2s
Declination −06° 42′ 28″
Apparent magnitude (V) 9.6 - 13.5 (quiet), < 5 (burst)
Spectral type M2III / White Dwarf
U−B color index  ?
B−V color index  ?
Variable type Recurrent nova
Radial velocity (Rv) ? km/s
Proper motion (μ) RA: ? mas/yr
Dec.: ? mas/yr
Parallax (π) ? ± ? mas
Distance 1,950 — 5,200 ly
600[1] — 1,600[2] pc)
Absolute magnitude (MV) ?
Other designations
HD 162214

RS Ophiuchi (RS Oph) is a recurrent nova system approximately 5,000 light-years away in the constellation Ophiuchus. In its quiet phase it has an apparent magnitude of about 12.5. It erupted in 1898, 1933, 1958, 1967, 1985, and 2006 and reached about magnitude 5 on average. The recurrent nova is produced by a white dwarf star and a red giant circling about each other in a close orbit. About every 20 years, enough material from the red giant builds up on the surface of the white dwarf to produce a thermonuclear explosion. The white dwarf orbits close to the red giant, with an accretion disc concentrating the overflowing atmosphere of the red giant onto the white dwarf. If the white dwarf accretes enough mass to reach the Chandrasekhar limit, about 1.4 solar mass (M), it may explode as a Type Ia supernova.

Eruptive history[edit]


The 1898 eruption was, in fact, not discovered until several years after it happened. Williamina Fleming discovered a nova-like spectrum in the Henry Draper Memorial photographs and announced it as a potential nova in 1904. This diagnosis was affirmed by Edward Charles Pickering in 1905, after which Annie Jump Cannon determined that RS Ophiuchi had likely reached maximum in 1898.


The 1933 outburst was first detected by Eppe Loreta, from Bologna, Italy. Loreta had been observing Y Ophiuchi when he serendipitously noticed a bright object about 50 arcminutes southwest of Y Oph. The detection of this luminous star resulted in the second recorded outburst of RS Oph. An independent discovery of this activity was made several days later by Leslie Peltier (P) while making his routine check of the variable.


The 1958 outburst was detected by Cyrus Fernald, located in Longwood, Florida. Fernald's monthly report for July 1958, containing 345 observations, displays a note in which he comments "Not too good of a month outside of the RS Oph observations (19 in total). It was interesting to watch the change in color as the star faded. It was reddish-yellow the first night, then yellowish-red, and so on. The last observation was the reddest star that I have ever seen." The crimson color of which Mr. Fernald speaks is indicative of the strong H-alpha emission displayed in the several days following the outburst.


The 1967 outburst was again detected by Cyrus Fernald (FE), however, Fernald was not given credit for the earliest observation of maximum. For on the same evening, Dr. Max Beyer (BY), located in Hamburg, Germany, observed the variable at 6th magnitude. Due to the 6-hour difference in time zones, Dr. Beyer was credited with the first report.


In January 1985, Warren Morrison of Peterborough, Canada discovered RS Oph to again be in outburst, reaching a maximum brightness of magnitude 5.4.

AAVSO light curve of RS Oph's 2006 outburst. Different colors reflect different bandpasses.


On February 12, 2006 a new outburst occurred, reaching magnitude 4.5. The opportunity was taken to observe it at different wavelengths.[3][4]

See also[edit]


  1. ^ Izumi Hachisu and Mariko Kato, "A Theoretical Light-Curve Model for the 1985 Outburst of RS Ophiuchi", ApJ 536(2000), p. L93; Online abstract
  2. ^ Kato (1991). "Theoretical light curve for the recurrent nova RS Ophiuchi - Determination of the white dwarf mass, composition, and distance". The Astrophysical Journal 369 (1): 471–474. Bibcode:1991ApJ...369..471K. doi:10.1086/169775. 
  3. ^ Bode et al. (2006). "Swift Observations of the 2006 Outburst of the Recurrent Nova RS Ophiuchi. I. Early X-Ray Emission from the Shocked Ejecta and Red Giant Wind". The Astrophysical Journal 652 (1): 629–635. arXiv:astro-ph/0604618. Bibcode:2006ApJ...652..629B. doi:10.1086/507980. 
  4. ^ Monnier et al. (2006). "No Expanding Fireball: Resolving the Recurrent Nova RS Ophiuchi with Infrared Interferometry". The Astrophysical Journal Letters 647 (2): L127–L130. arXiv:astro-ph/0607399. Bibcode:2006ApJ...647L.127M. doi:10.1086/507584. 

Further reading[edit]

External links[edit]