KOBEsim: A Bayesian observing strategy algorithm for planet detection in radial velocity blindsearch surveys
Abstract
Context. Groundbased observing time is precious in the era of exoplanet followup and characterization, especially in highprecision radial velocity instruments. Blindsearch radial velocity surveys thus require a dedicated observational strategy in order to optimize the observing time, which is particularly crucial for the detection of small rocky worlds at large orbital periods.
Aims: We developed an algorithm with the purpose of improving the efficiency of radial velocity observations in the context of exoplanet searches, and we applied it to the Kdwarfs Orbited By habitable Exoplanets experiment. Our aim is to accelerate exoplanet confirmations or, alternatively, reject false signals as early as possible in order to save telescope time and increase the efficiency of both blindsearch surveys and followup of transiting candidates.
Methods: Once a minimum initial number of radial velocity datapoints is reached in such a way that a periodicity starts to emerge according to generalized LombScargle periodograms, that period is targeted with the proposed algorithm, named KOBEsim. The algorithm selects the next observing date that maximizes the Bayesian evidence for this periodicity in comparison with a model with no Keplerian orbits.
Results: By means of simulated data, we proved that the algorithm accelerates the exoplanet detection, needing 2933% fewer observations and a 4147% smaller time span of the full dataset for lowmass planets (m_{p} < 10 M_{⊕}) in comparison with a conventional monotonic cadence strategy. For 20 M_{⊕} planets we found a 16% enhancement in the number of datapoints. We also tested KOBEsim with real data for a particular KOBE target and for the confirmed planet HD 102365 b. These two tests demonstrate that the strategy is capable of speeding up the detection by up to a factor of 2 (i.e., reducing both the time span and number of observations by half).
Based on observations collected at Centro Astronómico Hispano en Andalucía (CAHA) at Calar Alto, operated jointly by Instituto de Astrofísica de Andalucía (CSIC) and Junta de Andalucía.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 January 2023
 DOI:
 10.1051/00046361/202243938
 arXiv:
 arXiv:2210.11207
 Bibcode:
 2023A&A...669A..18B
 Keywords:

 planets and satellites: detection;
 methods: statistical;
 techniques: radial velocities;
 stars: solartype;
 Astrophysics  Earth and Planetary Astrophysics;
 Astrophysics  Instrumentation and Methods for Astrophysics
 EPrint:
 Accepted for publication in A$\&