1 van Leeuwen, F. Validation of the new Hipparcos reduction. Astron. Astrophys. 474, 653–664 (2007)

2 Boyajian, T. S. et al. Stellar diameters and temperatures. II: Main-sequence K- and M-stars. Astrophys. J. 757, 112 (2012)

3 Kiraga, M. & Stepien, K. Age–rotation–activity relations for M dwarf stars. Acta Astron. 57, 149–172 (2007)

4 Güdel, M., Audard, M., Reale, F., Skinner, S. L. & Linsky, J. L. Flares from small to large: X-ray spectroscopy of Proxima Centauri with XMM-Newton. Astron. Astrophys. 416, 713–732 (2004)

5 Kopparapu, R. K. et al. Habitable zones around main-sequence stars: new estimates. Astrophys. J. 765, 131 (2013)

6 Pepe, F. et al. The HARPS search for Earth-like planets in the habitable zone. I. Very low-mass planets around HD 20794, HD 85512, and HD 192310. Astron. Astrophys. 534, A58 (2011)

7 Anglada-Escudé, G. & Butler, R. P. The HARPS-TERRA Project. I: description of the algorithms, performance, and new measurements on a few remarkable stars observed by HARPS. Astrophys. J. Suppl. Ser. 200, 15 (2012)

8 Butler, R. P. et al. Attaining Doppler precision of 3 m s−1. Publ. Astron. Soc. Pacif. 108, 500–509 (1996)

9 Kürster, M. et al. The low-level radial velocity variability in Barnard’s star (= GJ 699): secular acceleration, indications for convective redshift, and planet mass limits. Astron. Astrophys. 403, 1077–1087 (2003)

10 Arriagada, P. et al. Two planetary companions around the K7 dwarf GJ 221: a hot super-Earth and a candidate in the sub-Saturn desert range. Astrophys. J. 771, 42 (2013)

11 Berdiñas, Z. M., Amado, P. J., Anglada-Escudé, G., Rodríguez-López, C. & Barnes, J. High-cadence spectroscopy of M-dwarfs. I: analysis of systematic effects in HARPS-N line profile measurements on the bright binary GJ 725A+B. Mon. Not. R. Astron. Soc. 459, 3551B (2016)

12 Sicardy, B. et al. A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation. Nature 478, 493–496 (2011)

13 Brown, T. M. et al. Las Cumbres Observatory Global Telescope Network. Publ. Astron. Soc. Pacific 125, 1031–1055 (2013)

14 Baluev, R. V. The impact of red noise in radial velocity planet searches: only three planets orbiting GJ 581? Mon. Not. R. Astron. Soc. 429, 2052–2068 (2013)

15 Tuomi, M., Jones, H. R. A., Barnes, J. R., Anglada-Escudé, G. & Jenkins, J. S. Bayesian search for low-mass planets around nearby M dwarfs—estimates for occurrence rate based on global detectability statistics. Mon. Not. R. Astron. Soc. 441, 1545–1569 (2014)

16 Haario, H., Laine, M., Mira, A. & Saksman, E. Dram: efficient adaptive MCMC. Stat. Comput. 16, 339–354 (2006)

17 Rajpaul, V., Aigrain, S. & Roberts, S. Ghost in the time series: no planet for Alpha Cen B. Mon. Not. R. Astron. Soc. 456, L6–L10 (2016)

18 Bonfils, X. et al. The HARPS search for southern extra-solar planets. X: A msini = 11M⊕ planet around the nearby spotted M dwarf GJ 674. Astron. Astrophys. 474, 293–299 (2007)

19 Barnes, J. R. et al. Precision radial velocities of 15 M5–M9 dwarfs. Mon. Not. R. Astron. Soc. 439, 3094–3113 (2014)

20 Ofir, A. Optimizing the search for transiting planets in long time series. Astron. Astrophys. 561, A138 (2014)

21 Kopparapu, R. k. et al. The inner edge of the habitable zone for synchronously rotating planets around low-mass stars using general circulation models. Astrophys. J. 819, 84 (2016)

22 Reiners, A. & Basri, G. The moderate magnetic field of the flare star Proxima Centauri. Astron. Astrophys. 489, L45–L48 (2008)

23 Vidotto, A. A. et al. Effects of M dwarf magnetic fields on potentially habitable planets. Astron. Astrophys. 557, A67 (2013)

24 Zuluaga, J. I., Bustamante, S., Cuartas, P. A. & Hoyos, J. H. The influence of thermal evolution in the magnetic protection of terrestrial planets. Astrophys. J. 770, 23 (2013)

25 Bolmont, E. et al. Water loss from Earth-sized planets in the habitable zones of ultracool dwarfs: implications for the planets of TRAPPIST-1. Preprint at http://arxiv.org/abs/1605.00616 (2016)

26 Tanaka, H., Takeuchi, T. & Ward, W. R. Three-dimensional interaction between a planet and an isothermal gaseous disk. I: corotation and Lindblad torques and planet migration. Astrophys. J. 565, 1257–1274 (2002)

27 Weidenschilling, S. J. Aerodynamics of solid bodies in the solar nebula. Mon. Not. R. Astron. Soc. 180, 57–70 (1977)

28 Snellen, I. et al. Combining high-dispersion spectroscopy with high contrast imaging: probing rocky planets around our nearest neighbors. Astron. Astrophys. 576, A59 (2015)

29 Lubin, P. A roadmap to interstellar flight. Preprint at http://arxiv.org/abs/1604.01356 (2016)

30 Delfosse, X. et al. Accurate masses of very low mass stars. IV. Improved mass-luminosity relations. Astron. Astrophys. 364, 217–224 (2000)

31 Haario, H., Saksman, E. & Tamminen, J. An adaptive Metropolis algorithm. Bernouilli 7, 223 (2001)

32 Tuomi, M. et al. Signals embedded in the radial velocity noise: periodic variations in the τ Ceti velocities. Astron. Astrophys. 551, A79 (2013)

33 Metropolis, N., Rosenbluth, A., Rosenbluth, M., Teller, A. & Teller, E. Equations of state valculations by fast computing machines. J. Chem. Phys. 21, 1087–1092 (1953)

34 Hastings, W. K. Monte Carlo sampling methods using Markov chains and their applications. Biometrika 57, 97–109 (1970)

35 Newton, M. A. & Raftery, A. E. Approximate Bayesian inference with the weighted likelihood bootstrap. J. R. Stat.Soc. B 56, 3–48 (1994)

36 Tuomi, M. A new cold sub-Saturnian candidate planet orbiting GJ 221. Mon. Not. R. Astron. Soc. 440, L1–L5 (2014)

37 Wright, J. T. & Howard, A. W. Efficient fitting of multiplanet Keplerian models to radial velocity and astrometry data. Astrophys. J. Suppl. Ser. 182, 205–215 (2009)

38 Scargle, J. D. Studies in astronomical time series analysis. I: modeling random processes in the time domain. Astrophys. J. Suppl. Ser. 45, 1–71 (1981)

39 Tuomi, M. Evidence for nine planets in the HD 10180 system. Astron. Astrophys. 543, A52 (2012)

40 Tuomi, M. & Anglada-Escudé, G. Up to four planets around the M dwarf GJ 163: sensitivity of Bayesian planet detection criteria to prior choice. Astron. Astrophys. 556, A111 (2013)

41 Berger, J. O. Statistical Decision Theory and Bayesian Analysis Section 3.3 (Springer, 1980)

42 Anglada-Escudé, G. et al. A dynamically-packed planetary system around GJ 667C with three super-Earths in its habitable zone. Astron. Astrophys. 556, A126 (2013)

43 Lomb, N. R. Least-squares frequency analysis of unequally spaced data. Astrophys. Space Sci. 39, 447–462 (1976)

44 Scargle, J. D. Studies in astronomical time series analysis. II: statistical aspects of spectral analysis of unevenly spaced data. Astrophys. J. 263, 835–853 (1982)

45 Zechmeister, M., Kürster, M. & Endl, M. The M dwarf planet search programme at the ESO VLT + UVES: a search for terrestrial planets in the habitable zone of M dwarfs. Astron. Astrophys. 505, 859–871 (2009)

46 Cumming, A. Detectability of extrasolar planets in radial velocity surveys. Mon. Not. R. Astron. Soc. 354, 1165–1176 (2004)

47 Ferraz-Mello, S. Estimation of periods from unequally spaced observations. Astron. J. 86, 619–624 (1981)

48 Baluev, R. V. Accounting for velocity jitter in planet search surveys. Mon. Not. R. Astron. Soc. 393, 969–978 (2009)

49 Endl, M. & Kürster, M. Toward detection of terrestrial planets in the habitable zone of our closest neighbor: Proxima Centauri. Astron. Astrophys. 488, 1149–1153 (2008)

50 Bonfils, X. et al. The HARPS search for southern extra-solar planets. XXXI: the M-dwarf sample. Astron. Astrophys. 549, A109 (2013)

51 Queloz, D. et al. No planet for HD 166435. Astron. Astrophys. 379, 279–287 (2001)

52 Robertson, P., Mahadevan, S., Endl, M. & Roy, A. Stellar activity masquerading as planets in the habitable zone of the M dwarf Gliese 581. Science 345, 440–444 (2014)

53 Donati, J.-F. & Brown, S. F. Zeeman–Doppler imaging of active stars. V: sensitivity of maximum entropy magnetic maps to field orientation. Astron. Astrophys. 326, 1135–1142 (1997)

54 Barnes, J. R. et al. Red Optical Planet Survey: a new search for habitable Earths in the southern sky. Mon. Not. R. Astron. Soc. 424, 591–604 (2012)

55 Press, W. H., Teukolsky, S. A., Vetterling, W. T. & Flannery, B. P. Numerical Recipes in FORTRAN. The Art of Scientific Computing 2nd edn, Section 4.1 (Cambridge Univ. Press, 1992)

56 Jenkins, J. S. et al. An activity catalogue of southern stars. Mon. Not. R. Astron. Soc. 372, 163–173 (2006)

57 Jenkins, J. S. et al. Metallicities and activities of southern stars. Astron. Astrophys. 485, 571–584 (2008)

58 Collins, K. A., Kielkopf, J. F. & Stassun, K. G. AstroImageJ: image processing and photometric extraction for ultra-precise astronomical light curves. Preprint at http://arxiv.org/abs/1601.02622 (2016)

59 Southworth, J. et al. High-precision photometry by telescope defocussing. VI: WASP-24, WASP-25 and WASP-26. Mon. Not. R. Astron. Soc. 444, 776–789 (2014)

60 Dawson, R. I. & Fabrycky, D. C. Radial velocity planets de-aliased: a new, short period for super-Earth 55 Cnc e. Astrophys. J. 722, 937–953 (2010)

61 Aigrain, S., Pont, F. & Zucker, S. A simple method to estimate radial velocity variations due to stellar activity using photometry. Mon. Not. R. Astron. Soc. 419, 3147–3158 (2012)

62 Gomes da Silva, J. et al. Long-term magnetic activity of a sample of M-dwarf stars from the HARPS program. II: activity and radial velocity. Astron. Astrophys. 541, A9 (2012)

63 Baliunas, S. L. et al. Chromospheric variations in main-sequence stars. Astrophys. J. 438, 269–287 (1995)