A candidate super-Earth planet orbiting near the snow line of Barnard’s star

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...

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Detalles Bibliográficos
Autores: Ribas, Ignasi, Tuomi, Mikko, Reiners, Ansgar, Butler, R.P., Morales, Juan Carlos, Perger, M., Dreizler, Stefan, Rodríguez-López, Cristina, González Hernández, Jonay I., Rosich, Albert, Feng, Fabo, Trifonov, T., Vogt, S. S., Caballero, J. A., Hatzes, Artie P., Herrero, Enrique, Jeffers, Sandra V., Lafarga, M., Murgas, Felipe, Nelson, R. P., Martínez, Eloy, Strachan, J. B. P., Tal-Or, Lev, Teske, J., Toledo-Padrón, B., Zechmeister, Mathias, Quirrenbach, Andreas, Amado, Pedro J., Azzaro, M., Béjar, Victor J. S., Barnes, John R., Berdiñas, Z. M., Burt, J., Coleman, G., Cortés-Contreras, M., Crane, J.D., Engle, S. G., Guinan, Edward F., Haswell, Carole A., Henning, Thomas, Holden, B., Jenkins, J., Jones, Hugh R. A., Kaminski, Adrian, Kiraga, M., Kürster, M., Lee, M. H., López González, Maria J., Montes, David, Morin, J., Ofir, A., Pallé, Enric, Rebolo López, Rafael, Reffert, S., Schweitzer, Andreas, Seifert, W., Shectman, S. A., Staab, Daniel, Street, R. A., Suárez Mascareño, A., Tsapras, Yiannis, Wang, Sharon X., Anglada-Escudé, Guillem
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2018
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/216305
Acceso en línea:http://hdl.handle.net/10261/216305
Access Level:acceso abierto
Palabra clave:Planet Candidates
Long-term Modulation
Stellar Rotation Period
American Association Of Variable Star Observers (AAVSO)
Zero-point Offsets
Descripción
Sumario: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. © 2018, Springer Nature Limited.

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