Hunt for additional planet companions: Revisiting bona-fide single RV planet systems.

Monday 2 July, 11:25

We present results from our Doppler survey with HARPS, FEROS and CARMENES for a
sample of 45 stars, which were previously reported to have a single bona
fide planet in orbit. Most of these planetary discoveries were announced
based on sparse RV data samples, insufficient precision and sometimes incomplete
phase coverage. Therefore, we aim to increase the observational efforts for
these targets in an attempt to detect additional planets. Our intermediate
results from the survey indicate that almost half of our survey
targets are showing strong indication of additional companions.
We already reported our first survey discovery of two additional planets
around the solar-type star HD27894, while the publication of nine more stars
with a clear multiple planet detection is in preparation. For those we have
conducted detailed statistical and dynamical analyses of the RV data and
studied the long-term stability. We have a strong reason to believe that a
sufficient fraction of the single RV planets are in fact: either a pair of
low-eccentricity near-resonant planets misinterpreted as a single planet,
or are a systems with a long-period massive neighbor, which can be revealed only
by increasing the temporal baseline of the observations. Since the multiple
planet systems of any kind are important for probing planetary formation and
evolution scenarios we advocate the importance of further follow-up of RV
planet hosts.

Submitted by