Barycentric Coordinates (Astronomy) Information
In astronomy, barycentric coordinates are non-rotating coordinates with origin at the center of mass of two or more bodies.
Within classical mechanics, this definition simplifies calculations and introduces no known problems. In the General Theory of Relativity, problems arise because, while it is possible, within reasonable approximations, to define the barycentre, the associated coordinate system does not fully reflect the inequality of clock rates at different locations. Brumberg explains how to set up barycentric coordinates in General Theory of Relativity.[1]
The coordinate systems involve a world-time, i.e., a global time coordinate that could be set up by telemetry. Individual clocks of similar construction will not agree with this standard, because they are subject to differing gravitational potentials or move at various velocities, so the world-time must be slaved to some ideal clock; that one is assumed to be very far from the whole self-gravitating system. This time standard is called Barycentric Coordinate Time, abbreviated "TCB."
Barycentric Osculating Orbital Elements for some objects in the Solar System:[2]
| Object | Semi-major axis (in AU) | Apoapsis (in AU) | Orbital period (in years) |
|---|---|---|---|
| C/2006 P1 (McNaught) | 2050 | 4100 | 92600 |
| Comet Hyakutake | 1700 | 3410 | 70000 |
| C/2006 M4 (SWAN) | 1300 | 2600 | 47000 |
| 2006 SQ372 | 799 | 1570 | 22600 |
| 2000 OO67 | 549 | 1078 | 12800 |
| 90377 Sedna | 506 | 937 | 11400 |
| 2007 TG422 | 501 | 967 | 11200 |
For objects at such high eccentricity, the Suns barycentric coordinates are more stable than heliocentric coordinates.[3]
References
- ^ Essential Relativistic Celestial Mechanics by Victor A. Brumberg (Adam Hilger, London, 1991) ISBN 0-7503-0062-0.
- ^ Horizons output (2011-01-30). "Barycentric Osculating Orbital Elements for 2007 TG422". http://home.comcast.net/~kpheider/2007TG422Barycenter.txt. Retrieved 2011-01-31. (Select Ephemeris Type:Elements and Center:@0)
- ^ Kaib, Nathan A.; Becker, Andrew C.; Jones, R. Lynne; Puckett, Andrew W.; Bizyaev, Dmitry; Dilday, Benjamin; Frieman, Joshua A.; Oravetz, Daniel J.; Pan, Kaike; Quinn, Thomas; Schneider, Donald P.; Watters, Shannon (2009). "2006 SQ372: A Likely Long-Period Comet from the Inner Oort Cloud". The Astrophysical Journal 695 (1): 268–275. arXiv:0901.1690. Bibcode 2009ApJ...695..268K. doi:10.1088/0004-637X/695/1/268.
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