The HARPS search for southern extra-solar planets - XXVIII. Up to seven planets orbiting HD 10180: probing the architecture of low-mass planetary systems

By C. Lovis, Damien Ségransan, M. Mayor, S. Udry, W. Benz, Jean-Loup Bertaux, F. Bouchy, A. Correia, Jacques Laskar, G. Curto and 4 more. 2010

174 citations recorded by the source corpus.

Low-mass extrasolar planets are presently being discovered at an increased pace by radial velocity and transit surveys, which opens a new window on planetary systems. Aims. We are conducting a high-precision radial velocity survey with the HARPS spectrograph, which aims at characterizing the population of ice giants and super-Earths around nearby solar-type stars. This will lead to a better understanding of their formation and evolution, and will yield a global picture of planetary systems from gas giants down to telluric planets. Methods. Progress has been possible in this field thanks in particular to the sub-m s-1 radial velocity precision achieved by HARPS. We present here new high-quality measurements from this instrument. Results. We report the discovery of a planetary system comprising at least five Neptune-like planets with minimum masses ranging from 12 to 25 M⊕, orbiting the solar-type star HD 10180 at separations between 0.06 and 1.4 AU. A sixth radial velocity signal is present at a longer period, probably caused by a 65-M⊕ object. Moreover, another body with a minimum mass as low as 1.4 M⊕ may be present at 0.02 AU from the star. This is the most populated exoplanetary system known to date. The planets are in a dense but still well separated configuration, with significant secular interactions. Some of the orbital period ratios are fairly close to integer or half-integer values, but the system does not exhibit any mean-motion resonances. General relativity effects and tidal dissipation play an important role to stabilize the innermost planet and the system as a whole. Numerical integrations show long-term dynamical stability provided true masses are within a factor ~3 from minimum masses. We further note that several low-mass planetary systems exhibit a rather "packed" orbital architecture with little or no space left for additional planets. In several cases, semi-major axes are fairly regularly spaced on a logarithmic scale, giving rise to approximate Titius-Bode-like (i.e. exponential) laws. These dynamical architectures can be interpreted as the signature of formation scenarios where type I migration and interactions between protoplanets play a major role. However, it remains challenging to explain the presence of so many Neptunes and super-Earths on non-resonant, well-ordered orbits within ~1−2 AU of the central star. Finally, we also confirm the marked dependence of planet formation on both metallicity and stellar mass. Very massive systems are all found around metal-rich stars more massive than the Sun, while low-mass systems are only found around metal-deficient stars less massive than the Sun.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/da40575d67d0e0201985239fe93f53a296593e1f

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Citations in the corpus

• A SUPER-EARTH TRANSITING A NAKED-EYE STAR (2011, background): “Only a few other stars are known to host as many planets: HD 10180 (Lovis et al. 2011), Kepler-11 (Lissauer et al. 2011), and the Sun.”
• ARCHITECTURE AND DYNAMICS OF KEPLER'S CANDIDATE MULTIPLE TRANSITING PLANET SYSTEMS (2011, background): “Some of the most recent RV planets are from the same population of small-planet, short-period multiples seen in the Kepler data (e.g., Lo Curto et al. 2010; Lovis et al. 2011).”
• Spacing of Kepler Planets: Sculpting by Dynamical Instability (2015, background): “This observation, that Kepler high multis are perched at the cliff of instability (see also Lovis et al. 2011; Fang & Margot 2013), as we suggest below, is most likely the 8 result of continuous sculpting.”
• State of the Field: Extreme Precision Radial Velocities (2016, background): “First, it was found that subtraction of scattered light (especially from the ThAr calibration fiber) near the Ca II 81 Presentation by Nuno Santos 82 Presentation by Paul Robertson H&K lines improved the logR′HK measurements (Lovis et al. 2011).”
• MIGRATION THEN ASSEMBLY: FORMATION OF NEPTUNE-MASS PLANETS INSIDE 1 AU (2011, background): “The model range encompasses nearly all of these, with HD 10180 (Lovis et al. 2011), HD 31527, and HD 136352 located closest to the bulk of the simulation points.”
• The HARPS search for Earth-like planets in the habitable zone - I. Very low-mass planets around HD 20794, HD 85512, and HD 192310 (2011, methodology): “Last but not least, we should mention the system around HD 10180, with Article published by EDP Sciences A58, page 1 of 16 seven extra-solar planets of low mass, among which is the lightest ever detected exoplanet HD 10180 b, with m ∗ sin i of only 1.5 M⊕ (Lovis et al. 2011b).”
• Identifying Exoplanets with Deep Learning: A Five-planet Resonant Chain around Kepler-80 and an Eighth Planet around Kepler-90 (2017, background): “…i, falls in the 18 HD 10180 (Lovis et al. 2011), shows six confidently detected radial velocity signals and up to three more speculative signals (Lovis et al. 2011; Tuomi 2012) which have not been found necessary in subsequent analyses (Kane & Gelino 2014). largest gap in orbital-period space…”