Astronomy and Astrophysics – Astrophysics – Earth and Planetary Astrophysics
Scientific paper
2011-05-24
Celestial Mechanics and Dynamical Astronomy, 2011, Vol. 111, Number 1-2, P. 235-266
Astronomy and Astrophysics
Astrophysics
Earth and Planetary Astrophysics
36 pages, 11 figures, 3 tables; Accepted to Celestial Mechanics and Dynamical Astronomy
Scientific paper
10.1007/s10569-011-9356-0
We use full available array of radial velocity data, including recently published HARPS and Keck observatory sets, to characterize the orbital configuration of the planetary system orbiting GJ876. First, we propose and describe in detail a fast method to fit perturbed orbital configuration, based on the integration of the sensitivity equations inferred by the equations of the original $N$-body problem. Further, we find that it is unsatisfactory to treat the available radial velocity data for GJ876 in the traditional white noise model, because the actual noise appears autocorrelated (and demonstrates non-white frequency spectrum). The time scale of this correlation is about a few days, and the contribution of the correlated noise is about 2 m/s (i.e., similar to the level of internal errors in the Keck data). We propose a variation of the maximum-likelihood algorithm to estimate the orbital configuration of the system, taking into account the red noise effects. We show, in particular, that the non-zero orbital eccentricity of the innermost planet \emph{d}, obtained in previous studies, is likely a result of misinterpreted red noise in the data. In addition to offsets in some orbital parameters, the red noise also makes the fit uncertainties systematically underestimated (while they are treated in the traditional white noise model). Also, we show that the orbital eccentricity of the outermost planet is actually ill-determined, although bounded by $\sim 0.2$. Finally, we investigate possible orbital non-coplanarity of the system, and limit the mutual inclination between the planets \emph{b} and \emph{c} orbits by $5^\circ-15^\circ$, depending on the angular position of the mutual orbital nodes.
No associations
LandOfFree
Orbital structure of the GJ876 extrasolar planetary system, based on the latest Keck and HARPS radial velocity data does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Orbital structure of the GJ876 extrasolar planetary system, based on the latest Keck and HARPS radial velocity data, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Orbital structure of the GJ876 extrasolar planetary system, based on the latest Keck and HARPS radial velocity data will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-515566