RS Ophiuchi

RS Ophiuchi A / B

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)
Characteristics
Spectral type	M2III / White Dwarf
U−B color index	?
B−V color index	?
Variable type	Recurrent nova
Astrometry
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, it may explode as a Type Ia supernova.

Novae

1898

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.

1933

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.

1958

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.

1967

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.

1985

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.

2006

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

• DM Lyrae

Notes

Further reading

• Sokoloski, J. L.; J. G. M. Luna, K. Mukai and Scott J. Kenyon (20 July 2006). "An X-ray-emitting blast wave from the recurrent nova RS Ophiuchi". Nature 442 (7100): 276–278. arXiv:astro-ph/0605326. Bibcode 2006Natur.442..276S. doi:10.1038/nature04893. PMID 16855584.  (First paragraph; Editor's summary)
• O'Brien, T. J.; M. F. Bode, R. W. Porcas, T. W. B. Muxlow, S. P. S. Eyres, R. J. Beswick, S. T. Garrington, R. J. Davis and A. Evans (20 July 2006). "An asymmetric shock wave in the 2006 outburst of the recurrent nova RS Ophiuchi". Nature 442 (7100): 279–281. arXiv:astro-ph/0606224. Bibcode 2006Natur.442..279O. doi:10.1038/nature04949. PMID 16855585.  (First paragraph; Editor's summary)
• Wallerstein, George; Tanya Harrison, Ulisse Munari, and Andrew Vanture (11 May 2008). "The Metallicity and Lithium Abundances of the Recurring Novae T CrB and RS Oph". Publications of the Astronomical Society of the Pacific 120 (867): 492–497. Bibcode 2008PASP..120..492W. doi:10.1086/587965.  ([1])

External links

Wikimedia Commons has media related to: RS Ophiuchi

• SIMBAD: HD 162214 -- Symbiotic Star
• AAVSO alert on 2006 eruption
• Sky and Telescope: RS Ophiuchi in Rare Outburst
• Variable Star Of The Month: RS Ophiuchi
• Jodrell Bank/MERLIN's first radio image of the blast wave and initial data
• Entry at Astronomy Picture of the Day
• Entry in the Variable Star Index
• Astronomers See Future Supernova Developing (SpaceDaily) July 25, 2006
• AAVSO: Recent Observations of RS Oph

In the news

• Britt, Robert Roy (6 April 2006). "Star Explodes Inside Atmosphere of Another". Space.com. http://www.space.com/scienceastronomy/060406_star_star.html. 
• Amos, Jonathan (7 April 2006). "'Dead star' erupts for big show". BBC News. http://news.bbc.co.uk/2/hi/science/nature/4885700.stm. 
• Berardelli, Phil (10 April 2006). "Exploding Star Within A Star Surprises Astronomers". Space Daily. http://www.spacedaily.com/reports/Exploding_Star_Within_A_Star_Surprises_Astronomers.html. 
• Than, Ker (19 July 2006). "Mystery of Explosive Star Solved". Space.com. http://www.space.com/scienceastronomy/060719_ophiuchi_nova.html. 
• "Nuclear Explosion On A Dead Star". Max-Planck-Gesellschaft via Science Daily. 20 July 2006. http://www.sciencedaily.com/releases/2006/07/060720092733.htm. 
• Cain, Fraser (24 July 2006). "Podcast: Inevitable Supernova". Universe Today. http://www.universetoday.com/2006/07/24/podcast-inevitable-supernova/.