Panchromatic JWST spectrum of WASP-121 b detects SiO and measures refractory-to-volatile ratios 3x stellar, consistent with mixed solid-gas accretion or migration with continued solid accretion.
A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
10 Pith papers cite this work. Polarity classification is still indexing.
abstract
We have constructed a grid of about 10,000 spherically symmetric and plane-parallel models with the MARCS program, and make it available for public use. Parameter ranges are: Teff=2500 to 8000 K, log g =log(GM/R2)= -1 to 5 (cgs) with various masses and radii, [Me/H]=-5 to +1, with [Alpha/Fe] = 0.0 and 0.4 and different choices of C and N abundances to also represent stars of types R, S and N, and with microturbulence parameters from 1 to 5 km/s. We also list fluxes in approximately 108,000 wavelength points. Underlying assumptions in addition to 1D stratification include hydrostatic equilibrium, MLT convection and LTE. A number of general properties of the models are discussed, in relation to the effects of changing blanketing and sphericity. Models are compared with other available grids and excellent agreement is found with plane-parallel models of Castelli and Kurucz within the overlapping parameter range. Although there are departures from the spherically symmetric NextGen models, the agreement with more recent PHOENIX models is gratifying. The models of the grid show regularities, but some interesting departures from general patterns occur for the coolest models due to the molecular opacities. We have tested rules of thumb concerning effects of blanketing and sphericity and found them to often be astonishingly accurate. Some interesting new phenomena have been discovered, such as the intricate coupling between blanketing and sphericity, and the strong effects of carbon enhancement on metal-poor models. We give further details of models and comparisons with observations in subsequent papers.
years
2026 10representative citing papers
High [Si/Mg] = 0.67 in NGC 1277 cannot be explained by standard models and suggests pair-instability supernovae from very massive early stars.
Non-Gaussian LSF shapes bias kinematic extraction from spectra; matching the LSF of templates to the target reduces dispersion bias below 1%.
Synthetic spectra tests show Zeeman broadening recovers M dwarf magnetic field strengths more reliably with joint abundance fitting and WAIC selection than with free line strengths or BIC/AIC, which underestimate by 30-50% in active cases.
Observational analysis of 21 giant stars shows Fe I+Fe II blend emission proportional to Ca II K with matching Teff power-law exponent and a slope break in the flux ratio at log g ≈ 2.5.
Mass of 13.7 Earth masses and density 0.4 g cm^{-3} measured for TOI-1883 b, a super-Neptune in the ridge regime around an early-M dwarf, with implications for disk migration and photoevaporation.
Multi-method spectroscopic analysis of 585 FGK dwarfs shows parameter scatters larger than internal errors, inducing sub-5% fractional uncertainties on derived exoplanet radius and mass.
NLTE analysis finds F_odd of 0.65 in one CEMP-rs star versus 0.23 in two CEMP-s stars, supporting distinct isotope ratios as a signature of different neutron-capture processes.
A synthesis of observational data on red novae as stellar merger events, including outburst properties, progenitor diversity, and long-term remnants.
The paper reviews techniques for measuring protostellar accretion, analyzes methodological differences and caveats in comparing observations with simulations, and outlines next steps for a fuller picture.
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The panchromatic JWST dayside spectrum of WASP-121 b reveals a refractory-rich formation
Panchromatic JWST spectrum of WASP-121 b detects SiO and measures refractory-to-volatile ratios 3x stellar, consistent with mixed solid-gas accretion or migration with continued solid accretion.
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Chemical hints of Population III stars from silicon abundances in massive galaxies
High [Si/Mg] = 0.67 in NGC 1277 cannot be explained by standard models and suggests pair-instability supernovae from very massive early stars.
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The Impact of Non-Gaussian Line Spread Functions on Stellar Kinematic Recovery: Consequences for Dynamical Models
Non-Gaussian LSF shapes bias kinematic extraction from spectra; matching the LSF of templates to the target reduces dispersion bias below 1%.
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On the stellar parameter dependence of the combined Fe I and Fe II chromospheric emission-line in the wings of the Ca II K line
Observational analysis of 21 giant stars shows Fe I+Fe II blend emission proportional to Ca II K with matching Teff power-law exponent and a slope break in the flux ratio at log g ≈ 2.5.
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The mass of TOI-1883 b: A low density super-Neptune in the ridge regime transiting an early-M dwarf
Mass of 13.7 Earth masses and density 0.4 g cm^{-3} measured for TOI-1883 b, a super-Neptune in the ridge regime around an early-M dwarf, with implications for disk migration and photoevaporation.
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gr8stars II : judgement day for spectroscopic parameter model systematics
Multi-method spectroscopic analysis of 585 FGK dwarfs shows parameter scatters larger than internal errors, inducing sub-5% fractional uncertainties on derived exoplanet radius and mass.
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Ba Isotope Ratio in CEMP-s and CEMP-rs Stars as a Signature of s-Process and i-Process
NLTE analysis finds F_odd of 0.65 in one CEMP-rs star versus 0.23 in two CEMP-s stars, supporting distinct isotope ratios as a signature of different neutron-capture processes.
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Red novae, their progenitors, and remnants
A synthesis of observational data on red novae as stellar merger events, including outburst properties, progenitor diversity, and long-term remnants.
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The Accretion Process on Protostars
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