A High-Precision Near-Infrared Survey for Radial Velocity Variable Low-Mass Stars Using Cshell and a Methane Gas Cell

Gagné, Jonathan; Plavchan, Peter; Gao, Peter; Anglada‐Escudé, G.; Furlan, Elise; Davison, C.; Tanner, Angelle; Henry, Todd J.; Riedel, Adric R.; Brinkworth, Carolyn; Latham, David W.; Bottom, Michael; White, R. J.; Mills, Sean M.; Beichman, C. A.; Johnson, John Asher; Ciardi, David R.; Wallace, J. Kent; Mennesson, Bertrand; Braun, Kaspar von; Vasisht, Gautam; Prato, L.; Kane, Stephen R.; Mamajek, Eric E.; Walp, Bernie; Crawford, Timothy J.; Rougeot, R.; Geneser, Claire; Catanzarite, Joseph

doi:10.3847/0004-637x/822/1/40

Cited by 232 publications

(25 citation statements)

References 146 publications

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“…Croll et al (2014) determined the barycentric radial velocity of Kepler-1520 to be -36.3 km s −1 which, combined with the Gaia DR2 parallax and proper motions, yields a space motion of (U, V, W) = (−34.8, −34.1, +1.6) km s −1 (barycentric) or (−45.9, −46.1, −5.7) km s −1 with respect to the Local Standard of Rest (LSR) of Schönrich et al (2010). This motion is not consistent with any of the known young co-moving groups cataloged by Banyan Σ (Gagné et al 2016) but is consistent with the older "thick disk" population of stars (Fuhrmann 2004).…”

Section: Revised Properties Of the Host Starsmentioning

confidence: 76%

Monitoring of the D doublet of neutral sodium during transits of two ‘evaporating’ planets

Gaidos

Hirano

Ansdell

2019

Monthly Notices of the Royal Astronomical Society

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Spectroscopic transit detection of constituents in winds from "evaporating" planets on close-in transiting orbits could provide desperately needed information on the composition, formation, and orbital evolution of such objects. We obtained high-resolution optical spectra of the host stars during a single transit of Kepler-1520b and two transits of K2-22b to search for transient, Doppler-shifted absorption in the D lines of neutral sodium. Sodium should be released in the same silicate vapor wind that lofts the dust responsible for the periodic "dips" in the light curve. We do not detect any absorption lines with depths >30% at the predicted Doppler-shifted wavelengths during any of the transits. Detection sensitivity is limited by instrumental resolution that dilutes the saturated lines, and blurring of the lines by Doppler acceleration due to the short orbital period of the planet and long integration times for these faint stars. A model of neutral sodium production, escape, and ionization by UV radiation suggests that clouds of partially ionized sodium that are comparable in size to the host stars and optically thick in the D lines could accompany the planets. We consider the prospects for future detections brought about by the TESS all-sky survey of brighter stars and the advent of high-resolution spectrographs on Extremely Large Telescopes.

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Section: Revised Properties Of the Host Starsmentioning

confidence: 76%

Monitoring of the D doublet of neutral sodium during transits of two ‘evaporating’ planets

Gaidos

Hirano

Ansdell

2019

Monthly Notices of the Royal Astronomical Society

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“…They do not overlap with any of the ELODIE, HIRES, or CARMENES data. Gagné et al (2016) concluded that hot, warm and cool Jupiter planets more massive than 2.3, 4.2, and 20 M Jup and with orbital periodicities of 1-10, 10-100, and 100-1000 d, respectively, can be excluded around the B component (our main CARMENES target) with a confidence of 95%. The CSHELL/IRTF relative velocities are not considered in our planetary search of Section 4 because they Article number, page 3 of 44 A&A proofs: manuscript no.…”

Section: Radial Velocities From the Literaturementioning

confidence: 95%

“…The radial velocity survey of Gagné et al (2016) using the CSHELL spectrograph (Tokunaga et al 1990) at the NASA Infrared Telescope Facility (IRTF) included observations of GJ 338 A and B at near-infrared wavelengths (K band) between 2014 March and 2014 December. They do not overlap with any of the ELODIE, HIRES, or CARMENES data.…”

Section: Radial Velocities From the Literaturementioning

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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“…Starspots on a rotating photosphere can introduce radial velocity variations (e.g., Andersen & Korhonen 2015). Gagné et al (2016) investigated the effect of starspots on radial velocity measurements and found that an active star shows a long-term radial velocity variation of 25-50 m s −1 in the near-infrared. In the nearinfrared, the spot-induced radial velocity signal is significantly reduced due to the lower contrast between spots on the photosphere at longer wavelengths.…”

Section: Comparison With the Previous Publicationsmentioning

confidence: 99%

Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664

Han

Muirhead

Swift³

et al. 2017

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Several low-mass eclipsing binary stars show larger than expected radii for their measured mass, metallicity, and age. One proposed mechanism for this radius inflation involves inhibited internal convection and starspots caused by strong magnetic fields. One particular eclipsing binary, T-Cyg1-12664, has proven confounding to this scenario. Çakırlı et al. measured a radius for the secondary component that is twice as large as model predictions for stars with the same mass and age, but a primary mass that is consistent with predictions. Iglesias-Marzoa et al. independently measured the radii and masses of the component stars and found that the radius of the secondary is not in fact inflated with respect to models, but that the primary is, which is consistent with the inhibited convection scenario. However, in their mass determinations, Iglesias-Marzoa et al. lacked independent radial velocity measurements for the secondary component due to the star's faintness at optical wavelengths. The secondary component is especially interesting, as its purported mass is near the transition from partially convective to a fully convective interior. In this article, we independently determined the masses and radii of the component stars of T-Cyg1-12664 using archival Kepler data and radial velocity measurements of both component stars obtained with IGRINS on the Discovery Channel Telescope and NIRSPEC and HIRES on the Keck Telescopes. We show that neither of the component stars is inflated with respect to models. Our results are broadly consistent with modern stellar evolutionary models for main-sequence M dwarf stars and do not require inhibited convection by magnetic fields to account for the stellar radii.

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A High-Precision Near-Infrared Survey for Radial Velocity Variable Low-Mass Stars Using Cshell and a Methane Gas Cell

Cited by 232 publications

References 146 publications

Monitoring of the D doublet of neutral sodium during transits of two ‘evaporating’ planets

Monitoring of the D doublet of neutral sodium during transits of two ‘evaporating’ planets

The CARMENES search for exoplanets around M dwarfs

Magnetic Inflation and Stellar Mass. I. Revised Parameters for the Component Stars of the Kepler Low-mass Eclipsing Binary T-Cyg1-12664

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