Metallicity and Temperature Indicators in M dwarf K band Spectra: Testing New & Updated Calibrations With Observations of 133 Solar Neighborhood M dwarfs

Abstract

We present K band spectra for 133 nearby (d < 33 parsecs) M dwarfs, including 18 M dwarfs with reliable metallicity estimates (as inferred from an FGK type companion), 11 M dwarf planet hosts, more than 2/3 of the M dwarfs in the Northern 8 pc sample, and several M dwarfs from the LSPM catalog. From these spectra, we measure equivalent widths of the Ca and Na lines, and a spectral index quantifying the absorption due to H2O opacity (the H2O-K2 index). Using empirical spectral types standards and synthetic models, we calibrate the H2O-K2 index as an indicator of an M dwarf's spectral type and effective temperature. We also present a revised relationship that estimates the [Fe/H] and [M/H] metallicities of M dwarfs from their Na I, Ca I, and H2O-K2 measurements. Comparisons to model atmosphere provide a qualitative validation of our approach, but also reveal an overall offset between the atomic line strengths predicted by models as compared to actual observations. Our metallicity estimates also reproduce expected correlations with Galactic space motions and H alpha emission line strengths, and return statistically identical metallicities for M dwarfs within a common multiple system. Finally, we find systematic residuals between our H2O-based spectral types and those derived from optical spectral features with previously known sensitivity to stellar metallicity, such as TiO, and identify the CaH1 index as a promising optical index for diagnosing the metallicities of near-solar M dwarfs.

132 pages, 48 figures. Paper resubmitted to ApJ

References in corpus (15)

• Some Aspects of Measurement Error in Linear Regression of Astronomical Data
• Constraining the Age-Activity Relation for Cool Stars: The SDSS DR5 Low-Mass Star Spectroscopic Sample
• Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes
• The Milky Way Tomography with SDSS: II. Stellar Metallicity
• The Solar Neighborhood XVII: Parallax Results from the CTIOPI 0.9m Program -- Twenty New Members of the RECONS 10 Parsec Sample
• Simulations of dynamo action in fully convective stars
• Revised metallicity classes for low-mass stars: dwarfs (dM), subdwarfs (sdM), extreme subdwarfs (esdM), and ultra subdwarfs (usdM)
• LSPM J1112+7626: detection of a 41-day M-dwarf eclipsing binary from the MEarth transit survey
• A Long-Period Jupiter-Mass Planet Orbiting the Nearby M Dwarf GJ849
• The HARPS search for southern extra-solar planets: XIV. Gl 176b, a super-Earth rather than a Neptune, and at a different period
• Metallicities of M Dwarf Planet Hosts from Spectral Synthesis
• Accurate M Dwarf Metallicities from Spectral Synthesis: A Critical Test of Model Atmospheres
• Exploring the Local Milky Way: M Dwarfs as Tracers of Galactic Populations
• The Narrowest M-dwarf Line Profiles and the Rotation-Activity Connection at Very Slow Rotation
• Mass and radius determinations for five transiting M-dwarf stars

Cited by in corpus (269)

• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• Temperate Earth-sized planets transiting a nearby ultracool dwarf star
• The Occurrence Rate of Small Planets around Small Stars
• Stellar Diameters and Temperatures II. Main Sequence K & M Stars
• LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) The survey science plan
• X-Shooter spectroscopy of young stellar objects in Lupus: Accretion properties of class II and transitional objects
• X-Shooter spectroscopy of young stellar objects: IV -- Accretion in low-mass stars and sub-stellar objects in Lupus
• How to Constrain Your M dwarf II: the mass-luminosity-metallicity relation from 0.075 to 0.70$M_{\odot }$
• The Habitability of Planets Orbiting M-dwarf Stars
• SWEET-Cat: A catalogue of parameters for Stars With ExoplanETs I. New atmospheric parameters and masses for 48 stars with planets
• An Earth-sized Planet in the Habitable Zone of a Cool Star
• The NASA-UC-UH Eta-Earth Program: IV. A Low-mass Planet Orbiting an M Dwarf 3.6 PC from Earth
• A Spectroscopic Catalog of the Brightest (J<9) M Dwarfs in the Northern Sky
• Wide companions to Hipparcos stars within 67 pc of the Sun
• The MUSCLES Treasury Survey III: X-ray to Infrared Spectra of 11 M and K Stars Hosting Planets
• Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars
• Near-infrared Metallicities, Radial Velocities and Spectral Types for 447 Nearby M Dwarfs
• Spectro-Thermometry of M dwarfs and their candidate planets: too hot, too cool, or just right?
• The Solar Neighborhood XXXVII: The Mass-Luminosity Relation for Main Sequence M Dwarfs
• The CARMENES search for exoplanets around M dwarfs: Different roads to radii and masses of the target stars
• Prospecting in late-type dwarfs: a calibration of infrared and visible spectroscopic metallicities of late-K and M dwarfs spanning 1.5 dex
• CARMENES input catalogue of M dwarfs. I. Low-resolution spectroscopy with CAFOS
• The UV and X-ray activity of the M dwarfs within 10pc of the Sun
• Abiotic O${}_2$ Levels on Planets around F, G, K, and M Stars: Possible False Positives for Life?
• An Excess of Jupiter Analogs in Super-Earth Systems
• Characterizing the Cool KOIs II. The M Dwarf KOI-254 and its Hot Jupiter
• Effect of UV Radiation on the Spectral Fingerprints of Earth-like Planets Orbiting M dwarfs
• The Field Substellar Mass Function Based on the Full-sky 20-pc Census of 525 L, T, and Y Dwarfs
• The TRENDS High-Contrast Imaging Survey. IV. The Occurrence Rate of Giant Planets around M-Dwarfs
• X-Shooter spectroscopy of young stellar objects: II. Impact of chromospheric emission on accretion rate estimates
• ACCESS I: An Optical Transmission Spectrum of GJ 1214b Reveals a Heterogeneous Stellar Photosphere
• CARMENES input catalogue of M dwarfs V. Luminosities, colours, and spectral energy distributions
• A nearby M star with three transiting super-Earths discovered by K2
• Zodiacal Exoplanets In Time (ZEIT) I: A Neptune-sized planet orbiting an M4.5 dwarf in the Hyades Star Cluster
• The CARMENES search for exoplanets around M dwarfs. Two temperate Earth-mass planet candidates around Teegarden's Star
• Comoving stars in Gaia DR1: An abundance of very wide separation co-moving pairs
• Characterizing the Cool Kepler Objects of Interest. New Effective Temperatures, Metallicities, Masses and Radii of Low-Mass Kepler Planet-Candidate Host Stars
• The Kepler Dichotomy among the M Dwarfs: Half of Systems Contain Five or More Coplanar Planets
• They might be giants: luminosity class, planet frequency, and planet-metallicity relation of the coolest Kepler target stars
• Stellar Diameters and Temperatures V. Eleven Newly Characterized Exoplanet Host Stars
• Constructing A Flexible Likelihood Function For Spectroscopic Inference
• The Surface UV Environment on Planets Orbiting M-Dwarfs: Implications for Prebiotic Chemistry & Need for Experimental Follow-Up
• Validation of Twelve Small Kepler Transiting Planets in the Habitable Zone
• Discovery of a wide planetary-mass companion to the young M3 star GU Psc
• Metallicity of M dwarfs III. Planet-metallicity and planet-stellar mass correlations of the HARPS GTO M dwarf sample
• Seventy six T dwarfs from the UKIDSS LAS: benchmarks, kinematics and an updated space density
• The M-dwarfs in Multiples (MinMs) survey - I. Stellar multiplicity among low-mass stars within 15 pc
• ARIADNE: Measuring accurate and precise stellar parameters through SED fitting
• M Dwarf Metallicities and Giant Planet Occurrence: Ironing Out Uncertainties and Systematics
• Spitzer Observations Confirm and Rescue the Habitable-Zone Super-Earth K2-18b for Future Characterization
• Kepler-445, Kepler-446 and the Occurrence of Compact Multiples Orbiting Mid-M Dwarf Stars
• Magnetic Inhibition of Convection and the Fundamental Properties of Low-Mass Stars. II. Fully Convective Main Sequence Stars
• Eleven Multi-planet Systems from K2 Campaigns 1 & 2 and the Masses of Two Hot Super-Earths
• Computing Intrinsic Lyman-alpha Fluxes of F5 V to M5 V Stars
• BANYAN. V. A Systematic All-Sky Survey for New Very Late-Type Low-Mass Stars and Brown Dwarfs in Nearby Young Moving Groups
• The CARMENES search for exoplanets around M dwarfs. Stellar atmospheric parameters of target stars with SteParSyn
• Scaling K2. I. Revised Parameters for 222,088 K2 Stars and a K2 Planet Radius Valley at 1.9 $R_{\oplus }$
• A Catalog of Cool Dwarf Targets for the Transiting Exoplanet Survey Satellite
• The CARMENES search for exoplanets around M dwarfs - Photospheric parameters of target stars from high-resolution spectroscopy
• The First Habitable Zone Earth-sized Planet from TESS. I: Validation of the TOI-700 System
• Trends in Ultracool Dwarf Magnetism. I. X-Ray Suppression and Radio Enhancement
• Metallicity of M dwarfs IV. A high-precision [Fe/H] and Teff technique from high-resolution optical spectra for M dwarfs
• Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets Around Low-Mass Stars: the TRAPPIST-1 System
• An empirical calibration to estimate cool dwarf fundamental parameters from H-band spectra
• The CARMENES search for exoplanets around M dwarfs -- Photospheric parameters of target stars from high-resolution spectroscopy. II. Simultaneous multiwavelength range modeling of activity insensitive lines
• Prospecting in Ultracool Dwarfs: Measuring the Metallicities of Mid- and Late-M Dwarfs
• Stellar parameters of early M dwarfs from ratios of spectral features at optical wavelengths
• Two Transiting Earth-size Planets Near Resonance Orbiting a Nearby Cool Star
• Exoplanets around Low-mass Stars Unveiled by K2
• Detecting and Constraining N${}_2$ Abundances in Planetary Atmospheres Using Collisional Pairs
• Heavy metal rules. I. Exoplanet incidence and metallicity
• The SPHINX M-dwarf Spectral Grid. I. Benchmarking New Model Atmospheres to Derive Fundamental M-Dwarf Properties
• Detection of Stars within $\sim$0.8 arcseconds of Kepler Objects of Interest
• SPIRou Input Catalogue: Global properties of 440 M dwarfs observed with ESPaDOnS at CFHT
• Fundamental properties of lower main-sequence stars
• BANYAN. IX. The Initial Mass Function and Planetary-Mass Object Space Density of the TW Hya Association
• The effect of Lyman $\alpha$ radiation on mini-Neptune atmospheres around M stars: application to GJ 436b
• K2 Discovers a Busy Bee: An Unusual Transiting Neptune Found in the Beehive Cluster
• Primeval very low-mass stars and brown dwarfs. I. Six new L subdwarfs, classification and atmospheric properties
• HADES RV Programme with HARPS-N at TNG XII. The abundance signature of M dwarf stars with planets
• PENELLOPE: the ESO data legacy program to complement the Hubble UV Legacy Library of Young Stars (ULLYSES) I. Survey presentation and accretion properties of Orion OB1 and $\sigma$-Orionis
• The Exemplar T8 Subdwarf Companion of Wolf 1130
• Influence of Stellar Flares on the Chemical Composition of Exoplanets and Spectra
• Calibrating the metallicity of M dwarfs in wide physical binaries with F-, G-, and K- primaries - I: High-resolution spectroscopy with HERMES: stellar parameters, abundances, and kinematics
• A Near-Infrared Spectroscopic Survey of 886 Nearby M Dwarfs
• The California Planet Survey IV: A Planet Orbiting the Giant Star HD 145934 and Updates to Seven Systems with Long-Period Planets
• Stellar activity with LAMOST. I. Spot configuration in Pleiades
• What are little worlds made of? Stellar abundances and the building blocks of planets
• Two temperate super-Earths transiting a nearby late-type M dwarf
• The Mass-Radius Relationship for Very Low Mass Stars: Four New Discoveries from the HATSouth Survey
• GJ 1214b revised. Improved trigonometric parallax, stellar parameters, orbital solution, and bulk properties for the super-Earth GJ 1214b
• The Gaia-ESO Survey: calibration strategy
• A More Precise Mass for GJ 1214 b and the Frequency of Multi-Planet Systems Around Mid-M Dwarfs
• A super-Earth and sub-Neptune transiting the late-type M dwarf LP 791-18
• New atmospheric parameters and spectral interpolator for the MILES cool stars
• Chemical Abundances of M-dwarfs from the APOGEE Survey. I. The Exoplanet Hosting Stars Kepler-138 and Kepler-186
• Characterizing the Cool KOIs. VI. H- and K-band Spectra of Kepler M Dwarf Planet-Candidate Hosts
• Spitzer Observations of GJ3470b: a Very Low-density Neptune-size Planet Orbiting a Metal-rich M dwarf
• Characterizing K2 Candidate Planetary Systems Orbiting Low-Mass Stars I: Classifying Low-mass Host Stars Observed During Campaigns 1-7
• Testing the Metal of Late-Type Kepler Planet Hosts with Iron-Clad Methods
• Stellar surface inhomogeneities as a potential source of the atmospheric signal detected in the K2-18 b transmission spectrum
• Stellar Characterization of M-dwarfs from the APOGEE Survey: A Calibrator Sample for the M-dwarf Metallicities
• Radii of 88 M Subdwarfs and Updated Radius Relations for Low-Metallicity M Dwarf Stars
• New M, L, and T Dwarf Companions to Nearby Stars from the Wide-field Infrared Survey Explorer
• Reaching the boundary between stellar kinematic groups and very wide binaries. III. Sixteen new stars and eight new wide systems in the beta Pictoris moving group
• Primeval very low-mass stars and brown dwarfs - VI. Population properties of metal-poor degenerate brown dwarfs
• The CARMENES search for exoplanets around M dwarfs. A Neptune-mass planet traversing the habitable zone around HD 180617
• X-shooter spectroscopy of young stars with disks. The TW Hydrae association as a probe of the final stages of disk accretion
• ODUSSEAS: A machine learning tool to derive effective temperature and metallicity for M dwarf stars
• Gaia-ESO Survey: The analysis of pre-main sequence stellar spectra
• A physically motivated and empirically calibrated method to measure effective temperature, metallicity, and Ti abundance of M dwarfs
• A Low-Mass Exoplanet Candidate Detected By $K2$ Transiting the Praesepe M Dwarf JS 183
• Characterizing the Cool KOIs. V. KOI-256: A Mutually Eclipsing Post-Common Envelope Binary
• A detailed analysis of the Gl 486 planetary system
• Fundamental M-dwarf parameters from high-resolution spectra using PHOENIX ACES models: I. Parameter accuracy and benchmark stars
• Detailed Chemical Abundances for a Benchmark Sample of M Dwarfs from the APOGEE Survey
• The Rotation-Activity Correlations in K and M dwarfs. I. Stellar parameters, compilations of $v\sin i$ and $P/\sin i$ for a large sample of late-K and M dwarfs
• WISE J072003.20-084651.2B Is A Massive T Dwarf
• Metallicity determination of M dwarfs - High-resolution IR spectroscopy
• A framework for the architecture of exoplanetary systems. I. Four classes of planetary system architecture
• The CARMENES search for exoplanets around M dwarfs: Convective shift and starspot constraints from chromatic radial velocities
• The Five Planets in the Kepler-296 Binary System All Orbit the Primary: A Statistical and Analytical Analysis
• The SDSS-III APOGEE Radial Velocity Survey of M dwarfs I: Description of Survey and Science Goals
• IGRINS Spectral Library
• Calibration of the MEarth Photometric System: Optical Magnitudes and Photometric Metallicity Estimates for 1802 Nearby M-dwarfs
• Simultaneous Multiwavelength Flare Observations of EV Lacertae
• Metallicity determination of M dwarfs - Expanded parameter range in metallicity and effective temperature
• The physical mechanism behind M dwarf metallicity indicators and the role of C and O abundances
• The Far Ultraviolet M-dwarf Evolution Survey. I. The Rotational Evolution of High-Energy Emissions
• Constraining atmospheric parameters and surface magnetic fields with $\text{ZeeTurbo}$: an application to SPIRou spectra
• The CARMENES search for exoplanets around M dwarfs -- A deep learning approach to determine fundamental parameters of target stars
• The EBLM project. II. A very hot, low-mass M dwarf in an eccentric and long period eclipsing binary system from SuperWASP
• Starspot mapping with adaptive parallel tempering. II. Application to TESS data for M-dwarf flare stars, AU Microscopii, YZ Canis Minoris, and EV Lacertae
• The habitability of stagnant-lid Earths around dwarf stars
• Fundamental Properties of Co-Moving Stars observed by $Gaia$
• The Metallicity of the CM Draconis System
• Stellar and Planetary Characterization of the Ross 128 Exoplanetary System from APOGEE Spectra
• A spectroscopic and proper motion search of Sloan digital Sky Survey: red subdwarfs in binary systems
• Planet Detectability in the Alpha Centauri System
• The CARMENES search for exoplanets around M dwarfs: Stable radial-velocity variations at the rotation period of AD~Leonis -- A test case study of current limitations to treating stellar activity
• The age-metallicity relation in the solar neighbourhood from a pilot sample of white dwarf-main sequence binaries
• Gaia Gaps and the Physics of Low-Mass Stars. I. The Fully Convective Boundary
• Exoplanet Characterization by Proxy: a Transiting 2.15 R_Earth Planet Near the Habitable Zone of the Late K dwarf Kepler-61
• Narrow-K-Band Observations of the GJ 1214 System
• Elemental Abundances of M Dwarfs Based on High-Resolution Near-Infrared Spectra: Verification by Binary Systems
• Examining the relationships between colour, $T_{\mathrm{eff}}$, and [M/H] for APOGEE K and M dwarfs
• M dwarf luminosity, radius, and $\alpha$-enrichment from $I$-band spectral features
• Warm Dust around Cool Stars: Field M Dwarfs with WISE 12 or 22 Micron Excess Emission
• Cleaning our Hazy Lens: Exploring Trends in Transmission Spectra of Warm Exoplanets
• Near Infrared Spectroscopy of Young Brown Dwarfs in Upper Scorpius
• The Mass-Activity relationships in M and K dwarfs. I. Stellar parameters of our sample of M and K dwarfs
• Automated identification of 2612 late-k and M dwarfs in the LAMOST commissioining data using the classification template fits
• CoRoT 101186644: A transiting low-mass dense M-dwarf on an eccentric 20.7-day period orbit around a late F-star
• Wolf 1130: A Nearby Triple System Containing a Cool, Ultramassive White Dwarf
• AD Leonis: Radial velocity signal of stellar rotation or spin-orbit resonance?
• Mapping the Local Halo: Statistical Parallax Analysis of SDSS Low-Mass Subdwarfs
• The CARMENES search for exoplanets around M dwarfs, Wolf 1069 b: Earth-mass planet in the habitable zone of a nearby, very low-mass star
• Measuring the magnetic field of young stars using iSHELL observations: BP Tau and V347 Aur
• Validation of small Kepler transiting planet candidates in or near the habitable zone
• The EBLM Project VI. The mass and radius of five low-mass stars in F+M binaries discovered by the WASP survey
• The Enigmatic Brown Dwarf WISEA J153429.75-104303.3 (aka "The Accident")
• Intrinsic Lyman alpha Profiles of High-Velocity G, K, and M Dwarfs
• Estimating the Ultraviolet Emission of M dwarfs with Exoplanets from Ca II and H$\alpha$
• An Increase in Small-planet Occurrence with Metallicity for Late-type Dwarf Stars in the Kepler Field and Its Implications for Planet Formation
• Photospheric properties and fundamental parameters of M dwarfs
• The discovery of a T6.5 subdwarf
• New Extinction and Mass Estimates from Optical Photometry of the Very Low Mass Brown Dwarf Companion CT Chamaeleontis B with the Magellan AO System
• The Lick-Carnegie Exoplanet Survey: Gliese 687b: A Neptune-Mass Planet Orbiting a Nearby Red Dwarf
• Elemental abundances of nearby M dwarfs based on high-resolution near-infrared spectra obtained by the Subaru/IRD survey: Proof of concept
• Two Small Temperate Planets Transiting Nearby M Dwarfs in K2 Campaigns 0 and 1
• Determination of spectroscopic parameters for 313 M dwarf stars from their APOGEE Data Release 16 H-band spectra
• Characterizing the Cool KOIs. VII. Refined Physical Properties of the Transiting Brown Dwarf LHS 6343 C
• Characterization of the Very Low Mass Secondary in the GJ 660.1AB System
• Revised age for CM Draconis and WD 1633+572: Toward a resolution of model-observation radius discrepancies
• Near Infrared Spectroscopy of M Dwarfs. I. CO Molecule as an Abundance Indicator of Carbon
• Stellar & Planetary Parameters for K2's Late Type Dwarf Systems from C1 to C5
• The Gold Standard: Accurate Stellar and Planetary Parameters for Eight Kepler M dwarf Systems Enabled by Parallaxes
• On High-Contrast Characterization of Nearby, Short-Period Exoplanets with Giant Segmented-Mirror Telescopes
• Brown dwarfs as ideal candidates for detecting UV aurora outside the Solar System: Hubble Space Telescope observations of 2MASS J1237+6526
• The quadruple pre-main sequence system LkCa3: Implications for stellar evolution models
• The Metallicity-Period-Mass Diagram of low-mass exoplanets
• The CARMENES search for exoplanets around M dwarfs: Not-so-fine hyperfine-split vanadium lines in cool star spectra
• Youth analysis of near infrared spectra of young low-mass stars and brown dwarfs
• Investigating Trends in Atmospheric Compositions of Cool Gas Giant Planets Using Spitzer Secondary Eclipses
• Effective Temperatures of Low-Mass Stars from High-Resolution H-band Spectroscopy
• Using High-Resolution Optical Spectra to Measure Intrinsic Properties of Low-Mass Stars: New Properties for KOI-314 and GJ 3470
• Precise Doppler Monitoring of Barnard's Star
• Chemical Properties of the Local Galactic Disk and Halo. I. Fundamental Properties of 1,544 Nearby, High Proper-Motion M dwarfs and subdwarfs
• Comparative high-resolution spectroscopy of M dwarfs -- exploring non-LTE effects
• ODUSSEAS: Upgraded version with new reference scale and parameter determinations for 82 planet-host M dwarf stars in SWEET-Cat
• Exoplanet Populations and their Dependence on Host Star Properties
• K2-288Bb: A Small Temperate Planet in a Low-mass Binary System Discovered by Citizen Scientists
• Extending the FIP bias sample to magnetically active stars. Challenging the FIP bias paradigm?
• SDSS/SEGUE Spectral Feature Analysis For Stellar Atmospheric Parameter Estimation
• Characterisation of 92 Southern TESS Candidate Planet Hosts and a New Photometric [Fe/H] Relation for Cool Dwarfs
• 2MASS J15491331-3539118: a new low-mass wide companion of the GQ Lup system
• Higher Compact Multiple Occurrence Around Metal-Poor M-Dwarfs and Late K-Dwarfs
• Optical and Near-Infrared Radial Velocity Content of M Dwarfs: Testing Models with Barnard's Star
• Complete X-ray census of Mdwarfs in the solar Neighborhood I. GJ 745 AB: Coronal-hole Stars in the 10 pc Sample
• Optical - Near Infrared Photometric Calibration of M-dwarf Metallicity and Its Application
• The LHS 1678 System: Two Earth-Sized Transiting Planets and an Astrometric Companion Orbiting an M Dwarf Near the Convective Boundary at 20 pc
• Metallicity Dependence of Giant Planets around M Dwarfs
• HAT-TR-318-007: a double-lined M-dwarf binary with total secondary eclipses discovered by HATNet and observed by K2
• Ultracool dwarf benchmarks with \emph{Gaia} primaries
• Estimating $T_{\mathrm{eff}}$, radius and luminosity of M-dwarfs using high resolution optical and NIR spectral features
• Metallicity, temperature, and gravity scales of M subdwarfs
• Search for bright nearby M dwarfs with Virtual Observatory tools
• Using autoencoders and deep transfer learning to determine the stellar parameters of 286 CARMENES M dwarfs
• Characterization of the Wolf 1061 Planetary System
• Lyman-$\alpha$ Observations of High Radial Velocity Low-Mass Stars Ross 1044 and Ross 825
• TESS discovery of a super-Earth orbiting the M dwarf star TOI-1680
• X-Shooter spectroscopy of FU Tau A
• Primeval very low-mass stars and brown dwarfs -- VII. The discovery of the first wide M + L extreme subdwarf binary
• Data-Driven Spectroscopy of Cool Stars at High Spectral Resolution
• The Solar Neighborhood XLVII: Comparing M Dwarf Models with Hubble Space Telescope Dynamical Masses and Spectroscopy
• Photometric observations of flares on AD Leo from GWAC-F30 and TESS
• Beyond the Local Volume. II. Population Scaleheights and Ages of Ultracool Dwarfs in Deep HST/WFC3 Parallel Fields
• Photometric Calibrations of M-dwarf Metallicity with Markov Chain Monte Carlo and Bayesian Inference
• A spectroscopically confirmed Gaia-selected sample of 318 new young stars within $\sim$200 pc
• M dwarfs in the b201 tile of the VVV survey: Colour-based Selection, Spectral Types and Light Curves
• A New Method for Characterizing Very-Low-Mass Companions with Low Resolution Near-Infrared Spectroscopy
• TESS discovery of two super-Earths orbiting the M-dwarf stars TOI-6002 and TOI-5713 near the radius valley
• Understanding Physical Properties of Young M-dwarfs: NIR spectroscopic studies
• Derivation of parameters for 3748 FGK stars using H-band spectra from APOGEE Data Release 14
• Identification of blue high proper motion objects in the Tycho-2 and 2MASS catalogues using Virtual Observatory tools
• Revising Properties of Planet-host Binary Systems I.: Methods and Pilot Study
• A transiting giant planet in orbit around a 0.2-solar-mass host star
• Cool and Data-Driven: An Exploration of Optical Cool Dwarf Chemistry with Both Data-Driven and Physical Models
• Optical BVRI Photometry of Common Proper Motion F/G/K+M Wide Separation Binaries
• Fundamental Parameters of $\sim$30,000 M dwarfs in LAMOST DR1 Using Data-driven Spectral Modeling
• The CARMENES search for exoplanets around M dwarfs -- A deep transfer learning method to determine Teff and [M/H] of target stars
• The GAPS programme at TNG XXVI. Magnetic activity in M stars: spectroscopic monitoring of AD Leonis
• Wide companions to M and L subdwarfs with Gaia and the Virtual Observatory
• Spectral characterization of young LT dwarfs
• Orbital Parameters for the Two Young Binaries VSB 111 and VSB 126
• Phase-dependent photometric and spectroscopic characterization of the MASTER-Net Optical Transient J212444.87+321738.3: an oxygen rich Mira
• The young low-mass star ISO-Oph-50: Extreme variability induced by a clumpy, evolving circumstellar disk
• COol Companions ON Ultrawide orbiTS (COCONUTS). III. A Very Red L6 Benchmark Brown Dwarf around a Young M5 Dwarf
• The Interior Structure Constants as an Age Diagnostic for Low-Mass, Pre-Main Sequence Detached Eclipsing Binary Stars
• Slow Magnetoacoustic Oscillations in Stellar Coronal Loops
• Optical constraints on the coldest metal-poor population
• Characterisation of close visual binaries from the AstraLux Large M Dwarf Survey
• GEMS JWST: Transmission spectroscopy of TOI-5205b reveals significant stellar contamination and a metal-poor atmosphere
• The CARMENES search for exoplanets around M dwarfs. A sub-Neptunian mass planet in the habitable zone of HN Lib
• HADES RV programme with HARPS-N at TNG XIV. A candidate super-Earth orbiting the M-dwarf GJ 9689 with a period close to half the stellar rotation period
• Correlating Intrinsic Stellar Parameters with Mg II Self-Reversal Depths
• Chromaticity of stellar activity in radial velocities : Anti-correlated families of lines on the M dwarf EV Lac with SPIRou and SOPHIE
• Performance of the Stellar Abundances and atmospheric Parameters Pipeline adapted for M dwarfs I. Atmospheric parameters from the spectroscopic module
• Large Interferometer For Exoplanets (LIFE). XIV. Finding terrestrial protoplanets in the galactic neighborhood
• M dwarf stars in the light of (future) exoplanet searches
• Two substellar survivor candidates; one found and one missing
• Characterization of Low Mass K2 Planet Hosts Using Near-Infrared Spectroscopy
• A New Brown Dwarf Orbiting an M star and An Investigation on the Eccentricity Distribution of Transiting Long-Period Brown Dwarfs
• M dwarfs and the fraction of high carbon-to-oxygen stars in the solar neighbourhood
• SAFARI I: A SPHERE discovery of a super metal-rich M dwarf companion to the star HD 86006
• Identification of young nearby runaway stars based on Gaia data and the lithium test
• M dwarf spectral indices at moderate resolution: accurate $T_{\mathrm{eff}}$ and [Fe/H] for 178 southern stars
• MANGOS II: Five new giant planets orbiting low-mass stars
• TOI-1743 b, TOI-5799 b, TOI-5799 c and TOI-6223 b: TESS discovery and validation of four super-Earth to Neptune-sized planets around M dwarfs
• Dynamical mass of the white dwarf in XY Ari: a test for intermediate polar X-ray spectral models
• M Subdwarf Research III. Spectroscopic Diagnostics for Breaking Parameter Degeneracy
• Characterising Young Visual M-dwarf Binaries with Near-Infrared Integral Field Spectra
• TOI-7166 b: A Habitable Zone mini-Neptune planet around a nearby low-mass star
• Spectroscopic and photometric monitoring of a poorly known high-luminous OH/IR star: IRAS 18278+0931
• A test field for Gaia. Radial velocity catalogue of stars in the South Ecliptic Pole
• Stellar-activity analysis of the nearby M dwarf GJ 526. Multi-dimensional Gaussian-process modelling of RV, FWHM and S-index
• The M-dwarf Ultraviolet Spectroscopic Sample I. Determining Stellar Parameters for Field Stars
• Ross 19B: An Extremely Cold Companion Discovered via the Backyard Worlds: Planet 9 Citizen Science Project
• Metallicities in M dwarfs: Investigating different determination techniques