[Paper Review] The CORALIE survey for southern extra-solar planets. XII. Orbital solutions for 16 extra-solar planets discovered with CORALIE

M. Mayor, S. Udry+5 more|ArXiv.org|Oct 11, 2003

Stellar, planetary, and galactic studiesPhysics and Astronomy39 references177 citations

TL;DR

This paper presents orbital solutions for 16 newly discovered exoplanets from the CORALIE survey using radial velocity measurements from the Euler telescope at La Silla Observatory. It identifies ten Jupiter-like planets on eccentric, long-period orbits, three short-period planets including a hot Jupiter, and two multi-planet systems—HD 82943 (resonant 2:1 orbital configuration) and HD 169830 (hierarchically structured)—highlighting challenges in constraining multi-planet systems due to limited phase coverage and orbital parameter degeneracy.

ABSTRACT

This paper summarizes the information gathered for 16 still unpublished exoplanet candidates discovered with the CORALIE echelle spectrograph mounted on the Euler Swiss telescope at La Silla Observatory. Amongst these new candidates, 10 are typical extrasolar Jupiter-like planets on intermediate- or long-period (100

Motivation & Objective

• To present and validate orbital solutions for 16 unpublished exoplanet candidates detected via radial velocity monitoring with the CORALIE spectrograph.
• To analyze the orbital characteristics of these planets, particularly focusing on eccentricity, period, and mass distribution in relation to known exoplanet trends.
• To investigate the dynamical behavior and stability of multi-planet systems, especially HD 82943 and HD 169830, where planet-planet interactions may influence evolution.
• To assess the impact of stellar activity and measurement uncertainty on orbital parameter determination, particularly in systems with limited phase coverage.
• To contribute to the statistical understanding of exoplanet architectures and their implications for planet formation and migration theories.

Proposed method

• Radial velocity measurements were obtained using the CORALIE echelle spectrograph on the 1.2-m Euler Swiss telescope at La Silla Observatory.
• Orbital solutions were derived using a 2-Keplerian model for multi-planet systems, with iterative fitting to radial velocity data over multiple epochs.
• Stellar parameters such as effective temperature, metallicity ([Fe/H]), and activity levels (via log(R′HK)) were inferred from spectroscopic analysis and calibrated using established indicators.
• Systematic uncertainties in orbital parameters were assessed, particularly for long-period components in multi-planet systems with incomplete phase coverage.
• The stability and dynamical structure of multi-planet systems were evaluated by examining period ratios and resonant configurations.
• Data were cross-verified with archival data and compared to known exoplanet trends, including period-eccentricity and metallicity correlations.

Experimental results

Research questions

• RQ1 What are the orbital parameters (period, eccentricity, mass) of 16 newly detected exoplanet candidates from the CORALIE survey?
• RQ2 How do the orbital characteristics of these planets compare to the broader sample of known exoplanets, particularly in terms of period-eccentricity and mass-metallicity trends?
• RQ3 To what extent do planet-planet interactions influence the dynamical evolution of multi-planet systems like HD 82943 and HD 169830?
• RQ4 How do measurement uncertainties and incomplete phase coverage affect the reliability of orbital solutions, especially for long-period components?
• RQ5 Do the observed properties of these systems, such as period ratios and mass ratios, support proposed correlations in multi-planet architectures?

Key findings

• Ten of the 16 planets are Jupiter-like, with periods between 100 and 1350 days and eccentricities ranging from 0.2 to 0.5, consistent with the majority of known exoplanets.
• HD 82943 hosts a resonant 2:1 orbital configuration (P₂/P₁ = 2/1), indicating strong planet-planet interactions that influence system evolution.
• HD 169830 is a non-resonant, hierarchically structured multi-planet system with a larger separation between planets, suggesting weaker dynamical coupling.
• Three short-period planets were detected: HD 6434, HD 121504, and HD 83443, with the latter being a hot Jupiter (P ≈ 2.5 days, e ≈ 0.05).
• The majority of host stars are metal-rich (high [Fe/H]), with only three stars showing metal deficiency, supporting the known correlation between planetary system formation and stellar metallicity.
• Orbital solutions for multi-planet systems remain uncertain due to limited phase coverage, particularly for long-period components, indicating that future measurements will likely refine current solutions.