Astronomy and Astrophysics – Astrophysics – Earth and Planetary Astrophysics
Scientific paper
2010-08-24
Astronomy and Astrophysics
Astrophysics
Earth and Planetary Astrophysics
21 pages, including 8 b/w figures, 4 color figures and 2 tables. Accepted to MNRAS
Scientific paper
We investigate potential biases in the measurements of exoplanet orbital parameters obtained from radial velocity observations for single-planet systems. We create a mock catalog of radial velocity data, choosing input planet masses, periods, and observing patterns from actual radial velocity surveys and varying input eccentricities. We apply Markov Chain Monte Carlo (MCMC) simulations and compare the resulting orbital parameters to the input values. We find that a combination of the effective signal-to-noise ratio of the data, the maximal gap in phase coverage, and the total number of periods covered by observations is a good predictor of the quality of derived orbit parameters. As eccentricity is positive definite, we find that eccentricities of planets on nearly circular orbits are preferentially overestimated, with typical bias of 1-2 times the median eccentricity uncertainty in a survey (e.g., 0.04 in the Butler et al. 2006 catalog). When performing population analysis, we recommend using the mode of the marginalized posterior eccentricity distribution to minimize potential biases. While the Butler et al. (2006) catalog reports eccentricities below 0.05 for just 17% of single-planet systems, we estimate that the true fraction of e < 0.05 orbits is about f(0.05)=38\pm 9%. For planets with P > 10 days, we find f(0.05)=28\pm 8% versus 10% from Butler et al. (2006). These planets either never acquired a large eccentricity or were circularized following any significant eccentricity excitation.
Ford Eric B.
Pan Margaret
Zakamska Nadia L.
No associations
LandOfFree
Observational biases in determining extrasolar planet eccentricities in single-planet systems 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 Observational biases in determining extrasolar planet eccentricities in single-planet systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Observational biases in determining extrasolar planet eccentricities in single-planet systems will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-524541