TWO SUPER-EARTHS ORBITING THE SOLAR ANALOG HD 41248 ON THE EDGE OF A 7:5 MEAN MOTION RESONANCE
- Departamento de Astronomia, Universidad de Chile, Camino el Observatorio 1515, Las Condes, Santiago, Casilla 36-D (Chile)
- Center for Astrophysics, University of Hertfordshire, College Lane Campus, Hatfield, Hertfordshire, AL10 9AB (United Kingdom)
- Institute for Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China)
- Main Astronomical Observatory of National Academy of Sciences of Ukraine, 27 Zabolotnoho, Kyiv 127 03680 (Ukraine)
There are a growing number of multi-planet systems known to be orbiting their host stars with orbital periods that place them in mean motion resonances (MMRs). These systems are generally in first-order resonances and dynamical studies have focused their efforts on understanding the origin and evolution of such dynamically resonant commensurabilities. Here we report the discovery of two super-Earths that are close to a second-order dynamical resonance orbiting the metal-poor ([Fe/H] = -0.43 dex) and inactive G2V star HD 41428. We analyzed 62 HARPS archival radial velocities for this star that, until now, exhibited no evidence for planetary companions. Using our new Bayesian Doppler signal detection algorithm, we find two significant signals in the data, with periods of 18.357 days and 25.648 days, indicating they could be part of a 7:5 second-order MMR. Both semi-amplitudes are below 3 m s{sup -1} and the minimum masses of the pair are 12.3 and 8.6 M{sub Circled-Plus }, respectively. Our simulations found that apsidal alignment stabilizes the system, and even though libration of the resonant angles was not seen, the system is affected by the presence of the resonance and could still occupy the 7:5 commensurability, which would be the first planetary configuration in such a dynamical resonance. Given the multitude of low-mass multi-planet systems that will be discovered in the coming years, we expect that more of these second-order resonant configurations will emerge from the data, highlighting the need for a better understanding of the dynamical interactions between forming planetesimals.
- OSTI ID:
- 22140205
- Journal Information:
- Astrophysical Journal, Vol. 771, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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