Precise radial velocities of giant stars. XIII. A second Jupiter orbiting in 4:3 resonance in the 7 CMa system

Luque, R.; Trifonov, T.; Reffert, S.; Quirrenbach, A.; Lee, M. H.; Albrecht, S.; Fredslund Andersen, M.; Antoci, V.; Grundahl, F.; Schwab, C.; Wolthoff, V.
Bibliographical reference

Astronomy and Astrophysics

Advertised on:
11
2019
Number of authors
11
IAC number of authors
1
Citations
8
Refereed citations
8
Description
We report the discovery of a second planet orbiting the K giant star 7 CMa based on 166 high-precision radial velocities obtained with Lick, HARPS, UCLES, and SONG. The periodogram analysis reveals two periodic signals of approximately 745 and 980 d, associated with planetary companions. A double-Keplerian orbital fit of the data reveals two Jupiter-like planets with minimum masses mb sini 1.9 MJ and mc sini 0.9 MJ, orbiting at semimajor axes of ab 1.75 au and ac 2.15 au, respectively. Given the small orbital separation and the large minimum masses of the planets, close encounters may occur within the time baseline of the observations; thus, a more accurate N-body dynamical modeling of the available data is performed. The dynamical best-fit solution leads to collision of the planets and we explore the long-term stable configuration of the system in a Bayesian framework, confirming that 13% of the posterior samples are stable for at least 10 Myr. The result from the stability analysis indicates that the two planets are trapped in a low-eccentricity 4:3 mean motion resonance. This is only the third discovered system to be inside a 4:3 resonance, making this discovery very valuable for planet formation and orbital evolution models.

RV data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/631/A136

Based on observations collected at Lick Observatory, University of California.

Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere under ESO programmes 078.C-0751, 079.C-0657, 081.C-0802, 082.C-0427, 289.C-5053, 0100.C-0414 and 0101.C-0232.

Related projects
Projects' name image
Exoplanets and Astrobiology
The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable
Enric
Pallé Bago