Oph 162225-240515

Oph 162225-240515

Observation data Epoch J2000      Equinox J2000
Constellation	Ophiuchus
Right ascension	16:22:25
Declination	-24 05 15

Oph 162225-240515, often abbreviated Oph1622, is a pair of brown dwarfs that have been reported as orbiting each other. The bodies are located in the constellation Ophiuchus and are about 400 light years away. Mass estimates of the two objects are uncertain, but they are probably each higher than the brown-dwarf/planet dividing line of 13 Jupiter masses: Close et al. (2007) estimate the mass of the primary, designated Oph1622A as 12–21 times that of Jupiter and 9–20 Jupiter masses for the less massive Oph1622B, while Luhman et al. (2007) assign values of 57 and 20 Jupiter masses. Oph1622B is located 1.94 arcseconds away from Oph1622A, at a position angle of 182°. The pair are estimated to be around 5 million years old.

Announced in the 2006-08-04 issue of Science by Ray Jayawardhana and Valentin D. Ivanov, the objects were discovered using telescopes of the European Southern Observatory's "New Technology Telescope" in La Silla, Chile. The masses were originally reported to be lower, at 14 and 7 Jupiter masses, which would have made the smaller object a planetary-mass object, or "planemo". The system was announced as the first reported binary system of objects this small. However later observations revised the masses upward, and both are above the 13 Jupiter mass dividing line between planets and brown dwarfs.

The distance between the two is approximately 240 Astronomical Units—a distance so great that Space.com wrote that "their connection is so tenuous ... that a passing star or brown dwarf could permanently separate the two objects." As such, the discovery was reported as casting doubt on the theory that such free-floating planet-like objects have been ejected from a stellar system, such an event being too violent to leave them in orbit around each other.

References

• Close, Laird M.; Zuckerman, B.; Song, Inseok; Barman, Travis; Marois, Christian; Rice, Emily L.; Siegler, Nick; MacIntosh, Bruce et al. (May 2007), "The Wide Brown Dwarf Binary Oph 1622-2405 and Discovery of a Wide, Low-Mass Binary in Ophiuchus (Oph 1623-2402): A New Class of Young Evaporating Wide Binaries?", The Astrophysical Journal 660 (2): 1492–1506, arXiv:astro-ph/0608574, Bibcode 2007ApJ...660.1492C, doi:10.1086/513417 
• Jayawardhana, R.; Ivanov, V. D. (September 2006), "Discovery of a young planetary-mass binary", Science 313 (5791): 1279–1281, Bibcode 2006Sci...313.1279J, doi:10.1126/science.1132128, PMID 16888101 
• Luhman, K. L.; Allers, K. N.; Jaffe, D. T.; Cushing, M. C.; Williams, K. A.; Slesnick, C. L.; Vacca, W. D. (April 2007), "Ophiuchus 1622-2405: Not a Planetary-Mass Binary", The Astrophysical Journal 659 (2): 1629–1636, arXiv:astro-ph/0701242, Bibcode 2007ApJ...659.1629L, doi:10.1086/512539, http://www.iop.org/EJ/article/0004-637X/659/2/1629/70185.html 
• http://www.space.com/scienceastronomy/060803_planemo_twins.html
• http://news.bbc.co.uk/1/hi/sci/tech/5241774.stm

External links

• http://www.sciencedaily.com/releases/2006/08/060804084105.htm
• http://www.spacedaily.com/reports/Astronomers_Discover_Twin_Planemos_999.html