Uncovering the planets and stellar activity of CoRoT-7 using only radial velocities

@article{Faria2016UncoveringTP,
  title={Uncovering the planets and stellar activity of CoRoT-7 using only radial velocities},
  author={Jo{\~a}o P. Faria and Rapha{\"e}lle D. Haywood and Brendon J. Brewer and Pedro Figueira and Mahmoudreza Oshagh and Alexandre Santerne and Nuno C. Santos},
  journal={arXiv: Earth and Planetary Astrophysics},
  year={2016}
}
Stellar activity can induce signals in the radial velocities of stars, complicating the detection of orbiting low-mass planets. We present a method to determine the number of planetary signals present in radial-velocity datasets of active stars, using only radial-velocity observations. Instead of considering separate fits with different number of planets, we use a birth-death Markov chain Monte Carlo algorithm to infer the posterior distribution for the number of planets in a single run. In a… 

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References

SHOWING 1-10 OF 34 REFERENCES
Planets and stellar activity: hide and seek in the CoRoT-7 system
Abstract Since the discovery of the transiting Super-Earth CoRoT-7b, several investigations have been made of the number and precise masses of planets present in the system, but they all yield
Activity-Related Radial Velocity Variation in Cool Stars
Planets have been detected orbiting several solar-type stars with the use of high-precision radial velocity (vr) measurements. While changes in vr can be measured with an accuracy of a few meters per
Detecting extrasolar planets from stellar radial velocities using Bayesian evidence
Stellar radial velocity (RV) measurements have proven to be a very successful method for detecting extrasolar planets. Analysing RV data to determine the parameters of the extrasolar planets is a
Do stellar magnetic cycles influence the measurement of precise radial velocities
The ever increasing level of precision achieved by present and future radial-velocity instruments is opening the way to discovering very low-mass, long-period planets (e.g. solar-system analogs).
Photospheric activity, rotation, and radial velocity variations of the planet-hosting star CoRoT-7
Context. The CoRoT satellite has recently discovered the transits of an Earth-like planet across the disc of a late-type magnetically active star dubbed CoRoT-7, while a second planet was detected
The CoRoT-7 planetary system: two orbiting super-Earths
We report on an intensive observational campaign carried out with HARPS at the 3.6 m telescope at La Silla on the star CoRoT-7. Additional simultaneous photometric measurements carried out with the
Stellar activity mimics a habitable-zone planet around Kapteyn's star
Kapteyn's star is an old M subdwarf believed to be a member of the Galactic halo population of stars. A recent study has claimed the existence of two super-Earth planets around the star based on
On the mass determination of super-Earths orbiting active stars: the CoRoT-7 system
Context. Due to the star activity, the masses of CoRoT-7b and CoRoT 7c are uncertain. Investigators of the CoRoT team have proposed several solutions, all but one of them larger than the initia l
Bayesian re-analysis of the radial velocities of Gliese 581. Evidence in favour of only four planetary companions
Aims. The Gliese 581 planetary system has received attention because it has been proposed to host a low-mass planet in its habitable zone. We re-analyse the radial velocity measurements reported to
Reassessing the radial-velocity evidence for planets around CoRoT-7
CoRoT-7 is an 11 th magnitude K-star whose light curve shows transits with depth of 0.3 mmag and a period of 0:854 d, superimposed on variability at the 1% level, due to the modulation of evolving
...
...