RS Ophiuchi
From Wikipedia, the free encyclopedia
 Recurrent nova RS Ophiuchus in eruption of Feb 2006 |
|
| Observation data Epoch 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 |
| B-V color index | ? |
| U-B color index | ? |
| Variable type | Dwarf 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 nova 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. The recurrent nova is produced by a white dwarf star and a red giant. 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 within the distended atmosphere of the red giant, with an accretion disc concentrating the atmosphere of the red giant onto the white dwarf.
Contents |
[edit] Novae
[edit] 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 Pickering in 1905, after which Annie Jump Cannon determined that RS Ophiuchi had likely reached maximum in 1898.
[edit] 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.
[edit] 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 reddist 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.
[edit] 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 the 6-hour difference in time zones, Dr. Beyer was credited with the first report.
[edit] 1985
In January 1985, Warren Morrison of Peterborough, Canada discovered RS Oph to again be in outburst.
[edit] 2006
On February 13, 2006 a new outburst occurred, reaching magnitude 4.5. The opportunity was taken to observe it at different wavelengths.
[edit] Supernova
The accretion of matter from the red giant has increased the mass of the white dwarf to only slightly below its Chandrasekhar limit. It is possible that its mass will continue to increase to beyond this limit; at which point a type Ia supernova would occur, which would destroy the star system in a spectacular explosion that will be visible from the Earth for several days, even after sunrise. The exact time period of this explosion is not known, but it is possible that it will occur within the next 100,000 years.[3] Note that it is not yet known whether the novae explosion removes all of the matter accreted onto the white dwarf since the last novae; if it does, then a supernovae will not happen.
[edit] Binary system
[edit] RS Ophiuchi A
[edit] RS Ophiuchi B
[edit] See also
[edit] Notes
- ^ Izumi Hachisu and Mariko Kato, "A Theoretical Light-Curve Model for the 1985 Outburst of RS Ophiuchi", ApJ 536(2000), p. L93; Online abstract
- ^ Mariko Kato, "Theoretical light curve for the recurrent nova RS Ophiuchi - Determination of the white dwarf mass, composition, and distance", ApJ 369(1991), p. 471; Online abstract
- ^ Pease, Roland. "Astronomers glimpse exploded star", BBC News, 23 July 2006.
[edit] 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: 276–278. DOI:10.1038/nature04893. (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: 279–281. DOI:10.1038/nature04949. (First paragraph; Editor's summary)
[edit] External links
- 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
- Astronomers See Future Supernova Developing (SpaceDaily) Jul 25, 2006
[edit] In the news
- Britt, Robert Roy. "Star Explodes Inside Atmosphere of Another", Space.com, 6 April 2006, 12:00 ET.
- Amos, Jonathan. "'Dead star' erupts for big show", BBC News, 7 April 2006.
- Berardelli, Phil. "Exploding Star Within A Star Surprises Astronomers", Space Daily, 10 April 2006.
- Than, Ker. "Mystery of Explosive Star Solved", Space.com, 19 July 2006, 13:00 ET.
- "Nuclear Explosion On A Dead Star", Max-Planck-Gesellschaft via Science Daily, 20 July 2006.
- Cain, Fraser. "Podcast: Inevitable Supernova", Universe Today, 24 July 2006.
 |
This variable star–related article is a stub. You can help Wikipedia by expanding it. |
 |
This binary or multiple star system–related article is a stub. You can help Wikipedia by expanding it. |
