<i>TESS</i> discovery of a sub-Neptune orbiting a mid-M dwarf TOI-2136

Gan, Tianjun; Soubkiou, Abderahmane; Wang, Sharon X.; Benkhaldoun, Z.; Mao, Shude; Artigau, Étienne; Fouqué, P.; Giacalone, Steven; Theissen, Christopher; Aganze, Christian; Collins, Karen A.; Shporer, Avi; Barkaoui, Khalid; Ghachoui, Mourad; Howell, Steve B.; Lamman, Claire; Burdanov, Artem; Cadieux, Charles; Chouqar, J.; Collins, Kevin I.; Cook, Neil J.; Delrez, Laetitia; Demory, Brice-Olivier; Doyon, René; Dransfield, Georgina; Dressing, Courtney D.; Ducrot, Elsa; Fan, Jiahao; Garcia, Lionel; Gill, Holden; Gillon, M.; Gnilka, Crystal L.; Chew, Y. Gómez Maqueo; Günther, Maximilian N.; Henze, Christopher E.; Huang, Chelsea X.; Jehin, Emmanuël; Jensen, Eric L. N.; Lin, Zitao; McCormac, J.; Murray, C. A.; Niraula, Prajwal; Pedersen, P. P.; Pozuelos, F. J.; Queloz, D.; Rackham, Benjamin V.; Savel, Arjun B.; Schanche, N.; Schwarz, Richard P.; Sebastian, Daniel; Thompson, S.; Timmermans, Mathilde; Triaud, A. H. M. J.; Vezie, Michael; Wells, Robert D.; Wit, Julien de; Ricker, G.; Vanderspek, R.; Latham, David W.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.

doi:10.1093/mnras/stac1448

Cited by 15 publications

(3 citation statements)

References 139 publications

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“…It has been used to measure TOI-1759b's mass through a measurement of a pRV signal of K = 2.3 ± 0.7 m s −1 (Martioli et al 2022). Similarly, it has been used to measure the mass of the sub-Neptunes orbiting TOI-2136 and TOI-1452 (Gan et al 2022;Cadieux et al, submitted), respectively, corresponding to signals at the K = 4.2 ± 1.4 m s −1 and 3.5 ± 0.9 m s −1 level. These discoveries are based on individual measurements at the 6 to 10 m s −1 accuracy level with typically four measurements (one polarimetric sequence) per epoch, which are limited by the modest S/N obtained on these relatively faint targets (H = 9.6−10.0) and do not represent a fundamental noise floor for the technique.…”

Section: Demonstrations Of the Line-by-line Methodsmentioning

confidence: 99%

Line-by-line Velocity Measurements: an Outlier-resistant Method for Precision Velocimetry

Artigau

Cadieux

Cook

et al. 2022

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We present a new algorithm for precision radial velocity (pRV) measurements, a line-by-line (LBL) approach designed to handle outlying spectral information in a simple but efficient manner. The effectiveness of the LBL method is demonstrated on two data sets, one obtained with SPIRou on Barnard’s star, and the other with the High Accuracy Radial velocity Planet Searcher (HARPS) on Proxima Centauri. In the near-infrared, the LBL provides a framework for meters-per-second-level accuracy in pRV measurements despite the challenges associated with telluric absorption and sky emission lines. We confirm with SPIRou measurements spanning 2.7 yr that the candidate super-Earth on a 233 day orbit around Barnard’s star is an artifact due to a combination of time sampling and activity. The LBL analysis of the Proxima Centauri HARPS post-upgrade data alone easily recovers the Proxima b signal and also provides a 2σ detection of the recently confirmed 5 day Proxima d planet, but argues against the presence of the candidate Proxima c with a period of 1900 days. We provide evidence that the Proxima c signal is associated with small, unaccounted systematic effects affecting the HARPS-TERRA template-matching radial velocity extraction method for long-period signals. Finally, the LBL framework provides a very effective activity indicator, akin to the FWHM derived from the cross-correlation function, from which we infer a rotation period of 92.1 − 3.5 + 4.2 days for Proxima.

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Section: Demonstrations Of the Line-by-line Methodsmentioning

confidence: 99%

Line-by-line Velocity Measurements: an Outlier-resistant Method for Precision Velocimetry

Artigau

Cadieux

Cook

et al. 2022

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“…APERO data analyzed with the LBL algorithm has been presented in Gan et al (2022b), Martioli et al (2022), andCadieux et al (2022), setting constraints at, or below, the m s −1 -level on phase-folded RV curves of sub-Neptune TESS discoveries. A major goal of the next version of APERO (version 0.8) is to call LBL recipes inside APERO to allow the LBL products to be automatically produced and integrated into the post-processed results (see Section 11.4).…”

Section: Lbl Analysismentioning

confidence: 99%

APERO: A PipelinE to Reduce Observations—Demonstration with SPIRou

Cook¹,

Artigau

Doyon

et al. 2022

PASP

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With the maturation of near-infrared high-resolution spectroscopy, especially when used for precision radial velocity, data reduction has faced unprecedented challenges in terms of how one goes from raw data to calibrated, extracted, and corrected data with required precisions of thousandths of a pixel. Here we present A PipelinE to Reduce Observations (apero), specifically focused on Spectro Polarimètre Infra ROUge (SPIRou), the near-infrared spectropolarimeter on the Canada–France–Hawaii Telescope (SPectropolarimètre InfraROUge, CFHT). In this paper, we give an overview of apero and detail the reduction procedure for SPIRou. apero delivers telluric-corrected 2D and 1D spectra as well as polarimetry products. apero enables precise stable radial velocity measurements on the sky (via the LBL algorithm), which is good to at least ∼2 m s−1 over the current 5 yr lifetime of SPIRou.

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“…While most of the observing time is dedicated to targets from the SPECULOOS catalog, Artemis does follow-up observations of other noteworthy exoplanets, including the ones from TESS and Kepler/K2 (Howell et al 2014). We refer the reader to the work by Gan et al (2022) Artemis' light curve of a sub-Neptune orbiting a mid-M dwarf TOI-2136 and to the work by Niraula et al (2020) showing a transit of an Earth-sized planet around an M3.5 dwarf observed with Artemis and several SSO telescopes. Artemis' follow-up observations of solar system minor bodies, e.g., photometric monitoring of asteroids, which display cometary activity and observations of occultation of stars by asteroids might be found in Devogèle et al (2021) andFernández-Valenzuela et al (2021), respectively.…”

Section: Photometric Performancementioning

confidence: 99%

SPECULOOS Northern Observatory: Searching for Red Worlds in the Northern Skies

Burdanov¹,

Wit²,

Gillon³

et al. 2022

PASP

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SPECULOOS is a ground-based transit survey consisting of six identical 1 m robotic telescopes. The immediate goal of the project is to detect temperate terrestrial planets transiting nearby ultracool dwarfs (late M-dwarf stars and brown dwarfs), which could be amenable for atmospheric research with the next generation of telescopes. Here, we report the developments of the northern counterpart of the project—SPECULOOS Northern Observatory, and present its performance during the first three years of operations from mid-2019 to mid-2022. Currently, the observatory consists of one telescope, which is named Artemis. The Artemis telescope demonstrates remarkable photometric precision, allowing it to be ready to detect new transiting terrestrial exoplanets around ultracool dwarfs. Over the period of the first three years after the installation, we observed 96 objects from the SPECULOOS target list for 6000 hr with a typical photometric precision of 0.5%, and reaching a precision of 0.2% for relatively bright non-variable targets with a typical exposure time of 25 s. Our weather downtime (clouds, high wind speed, high humidity, precipitation and/or high concentration of dust particles in the air) over the period of three years was 30% of overall night time. Our actual downtime is 40% because of additional time loss associated with technical problems.

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TESS discovery of a sub-Neptune orbiting a mid-M dwarf TOI-2136

Cited by 15 publications

References 139 publications

Line-by-line Velocity Measurements: an Outlier-resistant Method for Precision Velocimetry

Line-by-line Velocity Measurements: an Outlier-resistant Method for Precision Velocimetry

APERO: A PipelinE to Reduce Observations—Demonstration with SPIRou

SPECULOOS Northern Observatory: Searching for Red Worlds in the Northern Skies

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