Two planets around Kapteyn's star: a cold and a temperate super-Earth orbiting the nearest halo red dwarf

  title={Two planets around Kapteyn's star: a cold and a temperate super-Earth orbiting the nearest halo red dwarf},
  author={Guillem Anglada-Escud'e and Pamela Arriagada and Mikko Tuomi and Mathias Zechmeister and James S. Jenkins and Aviv Ofir and Stefan Dreizler and Enrico Gerlach and C. J. Marvin and A. Reiners and S. V. Jeffers and R. Paul Butler and Steven S. Vogt and Pedro J. Amado and Cristina Rodr'iguez-L'opez and Z. M. Berdi{\~n}as and J. Morin and Jeffrey D. Crane and Stephen A. Shectman and Ian B. Thompson and Mat'ias R. D'iaz and Eugenio Jose Rivera and L F Sarmiento and Hugh R. A. Jones},
  journal={Monthly Notices of the Royal Astronomical Society},
Exoplanets of a few Earth masses can be now detected around nearby low-mass stars using Doppler spectroscopy. In this paper, we investigate the radial velocity variations of Kapteyn's star, which is both a sub-dwarf M-star and the nearest halo object to the Sun. The observations comprise archival and new HARPS, HIRES and PFS Doppler measurements. Two Doppler signals are detected at periods of 48 and 120 days using likelihood periodograms and a Bayesian analysis of the data. Using the same… 

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