The CARMENES search for exoplanets around M dwarfs

Luque, R.; Nowak, G.; Πάλλη, Ε.; Kossakowski, D.; Trifonov, T.; Zechmeister, M.; Béjar, V. J. S.; Guillén, C. Cardona; Tal-Or, L.; Hidalgo, D.; Ribas, I.; Reiners, A.; Caballero, J. A.; Amado, P. J.; Quirrenbach, A.; Aceituno, J.; Cortés-Contreras, M.; Díez-Alonso, E.; Guenther, E. W.; Henning, Th.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Montes, D.; Morales, J. C.; Passegger, V. M.; Schmitt, J. H. M. M.; Schweitzer, A.

doi:10.1051/0004-6361/201833423

Cited by 37 publications

(32 citation statements)

References 63 publications

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“…An Earth-mass planet (OGLE-2016-BLG-1195Lb) in a 1 AU orbit was also discovered around another ultracool dwarf star by microlensing surveys (Shvartzvald et al 2017). Recently, more and more such low-mass planets have been subsequently discovered around these late M-dwarf stars, such as Teegarden's star (Zechmeister et al 2019), GJ 1265 (Luque et al 2018), GJ 1061 Msini from RV mass from RV + transit or TTV Fig. 1.…”

Section: Introductionmentioning

confidence: 98%

“…The masses of planets seem to correlate with the masses of their central stars. The names of typically planetary systems around very lowmass stars are labeled in green, including TRAPPIST-1, (Gillon et al 2016), Proxima Centauri (Anglada-Escudé et al 2016), Ross 128 (Bonfils et al 2018), LHS 1140 (Dittmann et al 2017), YZ Cet (Astudillo-Defru et al 2017), Teegarden s star (Zechmeister et al 2019), GJ 1214 (Charbonneau et al 2009), GJ 1265 (Luque et al 2018), GJ 1132 (Berta- Thompson et al 2015), GJ 1061 and GJ 357 (Luque et al 2019). In order to get some clues, as a first attempt, here we plot the masses of the observed exoplanets as a function of their stellar masses in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

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Super-Earth masses sculpted by pebble isolation around stars of different masses

Liu

Lambrechts

Johansen

et al. 2019

A&A

102

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We develop a pebble-driven core accretion model to study the formation and evolution of planets around stars in the stellar mass range of 0.08 M and 1 M . By Monte Carlo sampling of the initial conditions, the growth and migration of a large number of individual protoplanetary embryos are simulated in a population synthesis manner. We test two hypotheses for the birth locations of embryos: at the water ice line or log-uniformly distributed over entire protoplanetary disks. Two types of disks with different turbulent viscous parameters αt of 10 −3 and 10 −4 are also investigated, to shed light on the role of outwards migration of protoplanets. The forming planets are compared with the observed exoplanets in terms of masses, semimajor axes, metallicities and water contents. We find that gas giant planets are likely to form when the characteristic disk sizes are larger, the disk accretion rates are higher, the disks are more metal rich and/or their stellar hosts are more massive. Our model shows that 1) the characteristic mass of super-Earth is set by the pebble isolation mass. Super-Earth masses increase linearly with the mass of its stellar host, corresponding to one Earth mass around a late M-dwarf star and 20 Earth masses around a solar-mass star. 2) The low-mass planets up to 20 M⊕ can form around stars with a wide range of metallicities, while massive gas giant planets are preferred to grow around metal rich stars. 3) Super-Earth planets that are mainly composed of silicates, with relatively low water fractions can form from protoplanetary embryos at the water ice line in weakly turbulent disks where outwards migration is suppressed. However, if the embryos are formed over a wide range of radial distances, the super-Earths would end up having a distinctive, bimodal composition in water mass. Altogether, our model succeeds in quantitatively reproducing several important observed properties of exoplanets and correlations with their stellar hosts.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Super-Earth masses sculpted by pebble isolation around stars of different masses

Liu

Lambrechts

Johansen

et al. 2019

A&A

102

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“…This spectrograph is operated at the 3.5 m telescope on Calar Alto, Spain, and has been taking data since January 2016 (Quirrenbach et al 2016(Quirrenbach et al , 2018Reiners et al 2018a). So far CARMENES has been used in the discovery of several new planets (Reiners et al 2018b;Kaminski et al 2018;Ribas et al 2018;Luque et al 2018;Nagel et al 2019). All of these discoveries estimated the mass of the host star with the same procedure that we present in this work, even though Reiners et al (2018b), Kaminski et al (2018), and Ribas et al (2018) used slightly older data than those used in this work.…”

Section: Introductionmentioning

confidence: 99%

The CARMENES search for exoplanets around M dwarfs

Schweitzer

Passegger

Cifuentes

et al. 2019

A&A

Self Cite

179

177

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Aims. We determine the radii and masses of 293 nearby, bright M dwarfs of the CARMENES survey. This is the first time that such a large and homogeneous high-resolution (R > 80 000) spectroscopic survey has been used to derive these fundamental stellar parameters. Methods. We derived the radii using Stefan-Boltzmann's law. We obtained the required effective temperatures T eff from a spectral analysis and we obtained the required luminosities L from integrated broadband photometry together with the Gaia DR2 parallaxes. The mass was then determined using a mass-radius relation that we derived from eclipsing binaries known in the literature. We compared this method with three other methods: (1) We calculated the mass from the radius and the surface gravity log g, which was obtained from the same spectral analysis as T eff . (2) We used a widely used infrared mass-magnitude relation. (3) We used a Bayesian approach to infer stellar parameters from the comparison of the absolute magnitudes and colors of our targets with evolutionary models. Results. Between spectral types M0 V and M7 V our radii cover the range 0.1 R < R < 0.6 R with an error of 2-3% and our masses cover 0.09 M < M < 0.6 M with an error of 3-5%. We find good agreement between the masses determined with these different methods for most of our targets. Only the masses of very young objects show discrepancies. This can be well explained with the assumptions that we used for our methods.Article published by EDP Sciences A68, page 1 of 16 A&A 625, A68 (2019)

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“…The main goal of CARMENES is to discover and characterize Earth-like planets around an initial sample of about 300 M dwarfs (Reiners et al 2018b). To date, the program has already confirmed eight planet candidates from large-scale photometric and spectroscopic surveys (e.g., Trifonov et al 2018;Sarkis et al 2018) and detected more than ten new planets (e.g., Reiners et al 2018a;Kaminski et al 2018;Luque et al 2018Luque et al , 2019Ribas et al 2018;Nagel et al 2019;Perger et al 2019;Zechmeister et al 2019;Morales et al 2019).…”

Section: Introductionmentioning

confidence: 99%

The CARMENES search for exoplanets around M dwarfs

González-Álvarez

Osorio

Caballero

et al. 2020

A&A

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Aims. We report on radial velocity time series for two M0.0 V stars, GJ 338 B and GJ 338 A, using the CARMENES spectrograph, complemented by ground-telescope photometry from Las Cumbres and Sierra Nevada observatories. We aim to explore the presence of small planets in tight orbits using the spectroscopic radial velocity technique. Methods. We obtained 159 and 70 radial velocity measurements of GJ 338 B and A, respectively, with the CARMENES visible channel between 2016 January and 2018 October. We also compiled additional relative radial velocity measurements from the literature and a collection of astrometric data that cover 200 a of observations to solve for the binary orbit. Results. We found dynamical masses of 0.64 ± 0.07 M for GJ 338 B and 0.69 ± 0.07 M for GJ 338 A. The CARMENES radial velocity periodograms show significant peaks at 16.61 ± 0.04 d (GJ 338 B) and 16.3 +3.5 −1.3 d (GJ 338 A), which have counterparts at the same frequencies in CARMENES activity indicators and photometric light curves. We attribute these to stellar rotation. GJ 338 B shows two additional, significant signals at 8.27 ± 0.01 and 24.45 ± 0.02 d, with no obvious counterparts in the stellar activity indices. The former is likely the first harmonic of the star's rotation, while we ascribe the latter to the existence of a super-Earth planet with a minimum mass of 10.27 +1.47 −1.38 M ⊕ orbiting GJ 338 B. We have not detected signals of likely planetary origin around GJ 338 A. Conclusions. GJ 338 Bb lies inside the inner boundary of the habitable zone around its parent star. It is one of the least massive planets ever found around any member of stellar binaries. The masses, spectral types, brightnesses, and even the rotational periods are very similar for both stars, which are likely coeval and formed from the same molecular cloud, yet they differ in the architecture of their planetary systems.

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The CARMENES search for exoplanets around M dwarfs

Cited by 37 publications

References 63 publications

Super-Earth masses sculpted by pebble isolation around stars of different masses

Super-Earth masses sculpted by pebble isolation around stars of different masses

The CARMENES search for exoplanets around M dwarfs

The CARMENES search for exoplanets around M dwarfs

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