Research output: Contribution to journal › Article › peer-review
- I. Ribas
- A. Reiners
- R. P. Butler
- J. C. Morales
- M. Perger
- S. Dreizler
- C. Rodríguez-López
- J. I. González Hernández
- A. Rosich
- F. Feng
- T. Trifonov
- S. S. Vogt
- J. A. Caballero
- A. Hatzes
- E. Herrero
- S. V. Jeffers
- M. Lafarga
- F. Murgas
- E. Rodríguez
- J. B. P. Strachan
- L. Tal-Or
- J. Teske
- B. Toledo-Padrón
- M. Zechmeister
- A. Quirrenbach
- P. J. Amado
- M. Azzaro
- V. J. S. Béjar
- J. R. Barnes
- Z. M. Berdiñas
- G. Coleman
- M. Cortés-Contreras
- J. Crane
- S. G. Engle
- E. F. Guinan
- C. A. Haswell
- Th Henning
- B. Holden
- A. Kaminski
- M. Kiraga
- M. Kürster
- M. J. López-González
- D. Montes
- J. Morin
- A. Ofir
- E. Pallé
- R. Rebolo
- S. Reffert
- A. Schweitzer
- W. Seifert
- S. A. Shectman
- D. Staab
- R. A. Street
- A. Suárez Mascareño
- Y. Tsapras
- G. Anglada-Escudé
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Original language | English |
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Pages (from-to) | 365-368 |
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Number of pages | 4 |
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Journal | Nature |
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Volume | 563 |
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Issue | 7731 |
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Early online date | 14 Nov 2018 |
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DOIs | |
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Publication status | Published - 15 Nov 2018 |
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Abstract
Barnard’s star is a red dwarf, and has the largest proper motion (apparent motion across the sky) of all known stars. At a distance of 1.8 parsecs, it is the closest single star to the Sun; only the three stars in the α Centauri system are closer. Barnard’s star is also among the least magnetically active red dwarfs known and has an estimated age older than the Solar System. Its properties make it a prime target for planetary searches; various techniques with different sensitivity limits have been used previously, including radial-velocity imaging, astrometry and direct imaging, but all ultimately led to negative or null results. Here we combine numerous measurements from high-precision radial-velocity instruments, revealing the presence of a low-amplitude periodic signal with a period of 233 days. Independent photometric and spectroscopic monitoring, as well as an analysis of instrumental systematic effects, suggest that this signal is best explained as arising from a planetary companion. The candidate planet around Barnard’s star is a cold super-Earth, with a minimum mass of 3.2 times that of Earth, orbiting near its snow line (the minimum distance from the star at which volatile compounds could condense). The combination of all radial-velocity datasets spanning 20 years of measurements additionally reveals a long-term modulation that could arise from a stellar magnetic-activity cycle or from a more distant planetary object. Because of its proximity to the Sun, the candidate planet has a maximum angular separation of 220 milliarcseconds from Barnard’s star, making it an excellent target for direct imaging and astrometric observations in the future.
Notes
38 pages, 7 figures, 4 tables, author's version of published paper in Nature journal
ID: 15985969