Bibcode
Astudillo-Defru, N.; Díaz, R. F.; Bonfils, X.; Almenara, J. M.; Delisle, J.-B.; Bouchy, F.; Delfosse, X.; Forveille, T.; Lovis, C.; Mayor, M.; Murgas, F.; Pepe, F.; Santos, N. C.; Ségransan, D.; Udry, S.; Wünsche, A.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 605, id.L11, 7 pp.
Fecha de publicación:
9
2017
Revista
Número de citas
56
Número de citas referidas
54
Descripción
Exoplanet surveys have shown that systems with multiple low-mass planets
on compact orbits are common. Except for a few cases, however, the
masses of these planets are generally unknown. At the very end of the
main sequence, host stars have the lowest mass and hence offer the
largest reflect motion for a given planet. In this context, we monitored
the low-mass (0.13 M⊙) M dwarf YZ Cet (GJ 54.1, HIP 5643)
intensively and obtained radial velocities and stellar-activity
indicators derived from spectroscopy and photometry, respectively. We
find strong evidence that it is orbited by at least three planets in
compact orbits (POrb = 1.97, 3.06, 4.66 days), with the inner
two near a 2:3 mean-motion resonance. The minimum masses are comparable
to the mass of Earth (M sin i = 0.75 ± 0.13, 0.98 ± 0.14,
and 1.14 ± 0.17 M⊕), and they are also the
lowest masses measured by radial velocity so far. We note the
possibility for a fourth planet with an even lower mass of M sin i =
0.472 ± 0.096 M⊕ at POrb = 1.04 days.
An n-body dynamical model is used to place further constraints on the
system parameters. At 3.6 parsecs, YZ Cet is the nearest multi-planet
system detected to date.
Based on observations made with the HARPS instrument on the ESO 3.6 m
telescope under the program IDs 180.C-0886(A), 183.C-0437(A), and
191.C-0873(A) at Cerro La Silla (Chile).Radial velocity data (Table B.4)
are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/605/L11
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