A candidate super-Earth planet orbiting near the snow line of Barnard’s star
- Ribas, I;
- Tuomi, M;
- Reiners, A;
- Butler, RP;
- Morales, JC;
- Perger, M;
- Dreizler, S;
- Rodríguez-López, C;
- González Hernández, JI;
- Rosich, A;
- Feng, F;
- Trifonov, T;
- Vogt, SS;
- Caballero, JA;
- Hatzes, A;
- Herrero, E;
- Jeffers, SV;
- Lafarga, M;
- Murgas, F;
- Nelson, RP;
- Rodríguez, E;
- Strachan, JBP;
- Tal-Or, L;
- Teske, J;
- Toledo-Padrón, B;
- Zechmeister, M;
- Quirrenbach, A;
- Amado, PJ;
- Azzaro, M;
- Béjar, VJS;
- Barnes, JR;
- Berdiñas, ZM;
- Burt, J;
- Coleman, G;
- Cortés-Contreras, M;
- Crane, J;
- Engle, SG;
- Guinan, EF;
- Haswell, CA;
- Henning, Th;
- Holden, B;
- Jenkins, J;
- Jones, HRA;
- Kaminski, A;
- Kiraga, M;
- Kürster, M;
- Lee, MH;
- López-González, MJ;
- Montes, D;
- Morin, J;
- Ofir, A;
- Pallé, E;
- Rebolo, R;
- Reffert, S;
- Schweitzer, A;
- Seifert, W;
- Shectman, SA;
- Staab, D;
- Street, RA;
- Suárez Mascareño, A;
- Tsapras, Y;
- Wang, SX;
- Anglada-Escudé, G
- et al.
Published Web Location
https://arxiv.org/pdf/1811.05955.pdfAbstract
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 parsecs1, 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 known2,3 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 imaging4-6, astrometry7,8 and direct imaging9, 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.
Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.