A low-mass planet candidate orbiting Proxima Centauri at a distance of 1.5 AU.
Where this comes from
- Record sourced from PubMed, PMID 31998838.
- Also identified by DOI 10.1126/sciadv.aax7467 and PMC identifier 6962037.
- Licence recorded as CC BY-NC.
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Abstract
Our nearest neighbor, Proxima Centauri, hosts a temperate terrestrial planet. We detected in radial velocities evidence of a possible second planet with minimum mass <i>m</i> <sub>c</sub> sin <i>i</i> <sub>c</sub> = 5.8 ± 1.9<i>M</i> <sub>⊕</sub> and orbital period <math xmlns="http://www.w3.org/1998/Math/MathML"> <mrow> <mrow><msub><mi>P</mi> <mi>c</mi></msub> <mo>=</mo> <msubsup><mn>5.21</mn> <mrow><mo>-</mo> <mn>0.22</mn></mrow> <mrow><mo>+</mo> <mn>0.26</mn></mrow> </msubsup> </mrow> </mrow> </math> years. The analysis of photometric data and spectro-scopic activity diagnostics does not explain the signal in terms of a stellar activity cycle, but follow-up is required in the coming years for confirming its planetary origin. We show that the existence of the planet can be ascertained, and its true mass can be determined with high accuracy, by combining Gaia astrometry and radial velocities. Proxima c could become a prime target for follow-up and characterization with next-generation direct imaging instrumentation due to the large maximum angular separation of ~1 arc second from the parent star. The candidate planet represents a challenge for the models of super-Earth formation and evolution.