The HARPS search for southern extra-solar planets. X. A m sin i = 11 M_â planet around the nearby spotted M dwarf GJ 674

By X. Bonfils, M. Mayor, X. Delfosse, T. Forveille, M. Gillon, C. Perrier, S. Udry, F. Bouchy, C. Lovis, F. Pepe and 3 more. 2007

184 citations recorded by the source corpus.

Context. How planet properties depend on stellar mass is a key diagnostic of planetary formation mechanisms. Aims. This motivates planet searches around stars that are significantly more massive or less massive than the Sun, and in particular our radial velocity search for planets around very low-mass stars. Methods. As part of that program, we obtained measurements of GJ 674, an M 2.5 dwarf at d = 4.5 pc. These measurements have dispersion much in excess of their internal errors. An intensive observing campaign demonstrates that the excess dispersion is due to two superimposed coherent signals, with periods of 4.69 and 35 days. Results. These data are described well by a 2-planet Keplerian model where each planet has a ∼11 M⊕ minimum mass. A careful analysis of the (low-level) magnetic activity of GJ 674, however, demonstrates that the 35-day period coincides with the stellar rotation period. This signal therefore originates in a spot inhomogeneity modulated by stellar rotation. The 4.69-day signal, on the other hand, is caused by a bona-fide planet, GJ 674b. Conclusions. Its detection adds to the growing number of Neptune-mass planets around M-dwarfs and reinforces the emerging conclusion that this mass domain is much more populated than the Jovian mass range. We discuss the metallicity distributions of Md warfwith and without planets and find a low 11% probability that they are drawn from the same parent distribution. Moreover, we find tentative evidence that the host star metallicity correlates with the total mass of their planetary system.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/b352334084c1cb1240cc5ff8a394bd00e8fb14f5

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Citations in the corpus

Disentangling between stellar activity and planetary signals (2010, methodology): “5V dwarf hosting a planet with a 4.69-day period (Bonfils et al. 2007).”
Observational Evidence for Tidal Interaction in Close Binary Systems (2007, unknown): “Bonfils et al. (2007) found a similar situation for Gliese 674, for which the orbital period is 4.7 days and the rotation period of the M star is about 35 days.”
The effective temperature scale of M dwarfs (2013, background): “Moreover, M dwarfs are now known to host exoplanets, including super-Earth exoplanets (Bonfils et al. 2007, 2012, Udry et al. 2007).”
CARMENES input catalogue of M dwarfs. I. Low-resolution spectroscopy with CAFOS (2015, background): “The heterogeneities on the stellar surface of the almost-fully convective, rotating, M dwarfs, such as dark spots, may induce spurious radial-velocity variations at visible wavelengths (Bonfils et al. 2007; Reiners et al. 2010; Barnes et al. 2011; Andersen& Korhonen 2015; Robertson et al. 2015).”
Long-term magnetic activity of a sample of M-dwarf stars from the HARPS program I. Comparison of activity indices (2011, unknown): “C-0488(E) duced by extra-solar planets (Queloz et al. 2001; Bonfils et al. 2007; Huélamo et al. 2008).”
The Habitability of Planets Orbiting M-dwarf Stars (2016, background): “It was only the ninth planet to be discovered around a Main Sequence star (Bonfils et al., 2007).”
The CARMENES Search for Exoplanets around M Dwarfs: A Low-mass Planet in the Temperate Zone of the Nearby K2-18 (2018, background): “Bonfils et al. (2007) reported an anti-correlation for GJ 674, which is also an early M2.”
Stellar activity of planetary host star HD 189 733 (2008, methodology): “We observe a loop pattern as expected for an active region, which features a dark spot rotating on the stellar surface asalready described by Bonfils et al. (2007).”
Spectroscopic parameters for 451 stars in the HARPS GTO planet search program - Stellar [Fe/H] and the frequency of exo-Neptunes (2008, background): “…orbiting a solar-like star (Mayor & Queloz 1995), including several planets in the Neptune-mass regime (e.g. McArthur et al. 2004; Santos et al. 2004b; Butler et al. 2004; Vogt et al. 2005; Rivera et al. 2005; Bonfils et al. 2005a, 2007; Udry et al. 2006, 2007; Lovis et al. 2006; Melo et al. 2007).”
SOAP 2.0: A TOOL TO ESTIMATE THE PHOTOMETRIC AND RADIAL VELOCITY VARIATIONS INDUCED BY STELLAR SPOTS AND PLAGES (2014, background): “These correlations are often a powerful diagnostic to decide if the observed RV signal is of activity or planetary origin (e.g. Boisse et al. 2009; Bonfils et al. 2007; Queloz et al. 2001).”
The HARPS search for southern extra-solar planets - XVII. Super-Earth and Neptune-mass planets in multiple planet systems HD 47 186 and HD 181 433 (2008, background): “…et al. 2007), HARPS has discovered several Neptune-mass and SuperEarth exoplanets around solar-type stars (Santos et al. 2004; Udry et al. 2006; Lovis et al. 2006; Melo et al. 2008; Mayor et al. 2009) and M dwarfs (Bonfils et al. 2005; Udry et al. 2007a; Bonfils et al. 2007, Forveille et al. 2009).”
Characterization of the K2-18 multi-planetary system with HARPS: A habitable zone super-Earth and discovery of a second, warm super-Earth on a non-coplanar orbit (2017, methodology): “From the extracted spectra we also derived a number of activity indicators including the time series of the Hα index which is sensitive to chromospheric activity and is computed following the definition in Bonfils et al. (2007).”
A New Planet around an M Dwarf: Revealing a Correlation between Exoplanets and Stellar Mass (2007, background): “About 300 nearby M dwarfs are currently monitored by various Doppler surveys, and only 5 have been discovered to harbor one or more planets (Delfosse et al. 1998; Marcy et al. 1998, 2001; Endl et al. 2003; Bonfils et al. 2005b; Butler et al. 2006b; Bonfils et al. 2007).”
M dwarfs: effective temperatures, radii and metallicities (2008, background): “An increasing number of M dwarfs are now known to host exoplanets (e.g. Delfosse et al. 1998; Butler et al. 2004; Bonfils et al. 2007, Udry et al. 2007).”
CHROMOSPHERIC ACTIVITY AND JITTER MEASUREMENTS FOR 2630 STARS ON THE CALIFORNIA PLANET SEARCH (2010, background): “High chromospheric activity is empirically associated with both random and quasi-periodic velocities that occasionally mimic the reflex velocities from exoplanets (Henry, Donahue & Baliunas 2002; Queloz et al. 2001; Bonfils et al. 2007).”