Evidence for an external origin of heavy elements in hot DA white dwarfs by Barstow, M, Barstow, J, Casewell, S, Holberg, J, Hubeny, I

“…Using heavy element blanketed non-local thermodynamic equilibrium stellar atmosphere calculations, we have addressed the heavy element abundance patterns making completely objective measurements of abundance values and their error ranges using a X2 fitting technique. …”

B field in OB stars (BOB): The outstandingly strong magnetic field in the evolved He-strong star CPD −62° 2124 by Castro, N, Fossati, L, Hubrig, S, Järvinen, S, Przybilla, N, Nieva, M, Ilyin, I, Carroll, T, Schöller, M, Langer, N, Schneider, F, Simón-Díaz, S, Morel, T, Butler, K

“…The quantitative characterisation of the stellar atmosphere yields an effective temperature of 23 650 ± 250 K, a surface gravity of 3.95 ± 0.10 dex and a surface helium fraction of 0.35 ± 0.02 by number. …”

Hyperfine structure and isotope shift of neutral and singly ionized copper using Fourier transform spectroscopy by Xintong Li, Meina Liu, Huiting Ma, Jia Wei, Yu Wang, Zhenwen Dai

“…These transitions respectively cover wavelengths from 223.078 to 2461.4 nm for Cu I and from 224.77 to 1791.747 nm for Cu II. Since in the stellar atmosphere copper is mainly present as singly ionized species, the new HFS data of Cu II will be very valuable for more accurate astronomical spectral analysis related to copper.…”
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X-Ray and UV Observations of the Contact Binary KIC 9832227 by Dirk Pandel, Lawrence A. Molnar

“…Using simulations of the UV light curve with stellar atmosphere models, we deduce the presence of a starspot near the polar region of the primary, and we determine the time of primary eclipse.…”
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Bridging High-density Electron Beam Coronal Transport and Deep Chromospheric Heating in Stellar Flares by Adam F. Kowalski

“…The optical and near-ultraviolet (NUV) continuum radiation in M-dwarf flares is thought to be the impulsive response of the lower stellar atmosphere to magnetic energy release and electron acceleration at coronal altitudes. …”
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Deconstructing Photospheric Spectral Lines in Solar and Stellar Flares by Aaron J. Monson, Mihalis Mathioudakis, Adam F. Kowalski

“…We employ radiative–hydrodynamic and radiative transfer calculations to simulate the response of the solar/stellar atmosphere to electron beam heating and synthesize spectral lines of Fe i to investigate the line-of-sight velocity fields information available from Doppler shifts of the emergent intensity profile. …”
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Disentangling the Planet from the Star in Late-Type M Dwarfs: A Case Study of TRAPPIST-1g by Wakeford, HR, Lewis, NK, Fowler, J, Bruno, G, Wilson, TJ, Moran, SE, Valenti, J, Batalha, NE, Filippazzo, J, Bourrier, V, Hörst, SM, Lederer, SM, de Wit, J

“…The atmospheres of late M stars represent a significant challenge in the characterization of any transiting exoplanets because of the presence of strong molecular features in the stellar atmosphere. TRAPPIST-1 is an ultracool dwarf, host to seven transiting planets, and contains its own molecular signatures that can potentially be imprinted on planetary transit lightcurves as a result of inhomogeneities in the occulted stellar photosphere. …”
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The Radial Velocity Experiment (RAVE): First data release by Steinmetz, M, Zwitter, T, Siebert, A, Watson, F, Freeman, K, Munari, U, Campbell, R, Williams, M, Seabroke, G, Wyse, R, Parker, Q, Bienayme, O, Roeser, S, Gibson, B, Gilmore, G, Grebel, E, Helmi, A, Navarro, J, Burton, D, Cass, C, Dawe, J, Fiegert, K, Hartley, M, Russell, K, Saunders, W

“…We present the first data release of the Radial Velocity Experiment (RAVE), an ambitious spectroscopic survey to measure radial velocities and stellar atmosphere parameters (temperature, metallicity, and surface gravity) of up to one million stars using the Six Degree Field multiobject spectrograph on the 1.2 m UK Schmidt Telescope of the Anglo-Australian Observatory. …”

Far-infrared line spectra of active galaxies from the Herschel/PACS spectrometer: The complete database by Fernández-Ontiveros, J, Spinoglio, L, Pereira-Santaella, M, Malkan, M, Andreani, P, Dasyra, K

“…The new [O iv] 25.9μm /[O iii] 88μm versus [Ne iii] 15.6μm /[Ne ii] 12.8μm diagram is proposed as the best diagnostic to separate (1) AGN activity from any kind of star formation and (2) low-metallicity dwarf galaxies from starburst galaxies. Current stellar atmosphere models fail to reproduce the observed [O iv] 25.9μm /[O iii] 88μm ratios, which are much higher when compared to the predicted values. …”

Disentangling the Planet from the Star in Late-Type M Dwarfs: A Case Study of TRAPPIST-1g by Wakeford, HR, Lewis, NK, Fowler, J, Bruno, G, Wilson, TJ, Moran, SE, Valenti, J, Batalha, NE, Filippazzo, J, Bourrier, V, Hörst, SM, Lederer, SM, de Wit, J

“…The atmospheres of late M stars represent a significant challenge in the characterization of any transiting exoplanets because of the presence of strong molecular features in the stellar atmosphere. TRAPPIST-1 is an ultracool dwarf, host to seven transiting planets, and contains its own molecular signatures that can potentially be imprinted on planetary transit lightcurves as a result of inhomogeneities in the occulted stellar photosphere. …”
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The photospheric abundances of active binaries - 1. Detailed analysis of HD 113816 (IS Vir) and HD 119285 (V851 Cen) by Katz, D, Favata, F, Aigrain, S, Micela, G

“…The high-resolution optical spectra of the two X-ray active binaries RS CVn stars HD 113816 (IS Vir) and HD 119285 (V851 Cen) are analysed and their Na, Mg, Al, Si, Ca, Sc, Ti, Co and Ni contents determined, in the framework of a larger program of chemical analysis of RS CVn stellar atmosphere. The analysis of IS Vir and V851 Cen is performed with three different LTE methods. …”

Left Ringing: Betelgeuse Illuminates the Connection between Convective Outbursts, Mode Switching, and Mass Ejection in Red Supergiants by Morgan MacLeod, Andrea Antoni, Caroline D. Huang, Andrea Dupree, Abraham Loeb

“…The dimming event has been attributed to a surface mass ejection, in which rising material drove shocks through the stellar atmosphere and expelled some material, partially obscuring the star as it formed molecules and dust. …”
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Two Different Weak Modulations in ab-type RR Lyrae Variable V838 Cyg, and Potential Influence of Metal Abundance on Blazhko Modulation by L.-J. Li, S.-B. Qian, X.-D. Shi, L.-Y. Zhu

“…We infer that the relatively high metal abundance will promote convection in the outer stellar atmosphere, and then inhibit those factors (turbulence, shock wave, etc.) that may cause Blazhko modulation. …”
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The VLT-FLAMES Tarantula Survey: XXIV. Stellar properties of the O-type giants and supergiants in 30 Doradus by Ramírez-Agudelo, O, Sana, H, de Koter, A, Tramper, F, Grin, N, Schneider, F, Langer, N, Puls, J, Markova, N, Bestenlehner, J, Castro, N, Crowther, P, Evans, C, García, M, Gräfener, G, Herrero, A, van Kempen, B, Lennon, D, Maíz Apellániz, J, Najarro, F, Sabín-Sanjulián, C, Simón-Díaz, S, Taylor, W, Vink, J

“…We apply an automated method for quantitative spectroscopic analysis of O stars combining the non-LTE stellar atmosphere model fastwind with the genetic fitting algorithm pikaia to determine the following stellar properties: effective temperature, surface gravity, mass-loss rate, helium abundance, and projected rotational velocity. …”

The MUSCLES Extension for Atmospheric Transmission Spectroscopy: UV and X-Ray Host-star Observations for JWST ERS & GTO Targets by Patrick R. Behr, Kevin France, Alexander Brown, Girish Duvvuri, Jacob L. Bean, Zachory Berta-Thompson, Cynthia Froning, Yamila Miguel, J. Sebastian Pineda, David J. Wilson, Allison Youngblood

“…The SEDs are composite spectra using data from the Chandra X-ray Observatory and XMM-Newton, the Hubble Space Telescope, BT-Settl stellar atmosphere models, and scaled spectra of proxy stars of similar spectral type and activity. …”
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A Spitzer Transmission Spectrum for the Exoplanet Gj 436b, Evidence for Stellar Variability, and Constraints on Dayside Flux Variations by Knutson, Heather A., Madhusudhan, Nikku, Cowan, Nicolas B., Christiansen, Jessie L., Agol, Eric, Deming, Drake, Desert, Jean-Michel, Charbonneau, David, Henry, Gregory W., Homeier, Derek, Langton, Jonathan, Laughlin, Gregory, Seager, Sara

“…We compare the limb-darkening coefficients predicted by PHOENIX and ATLAS stellar atmosphere models and discuss the effect that these coefficients have on the measured planet-star radius ratios given GJ 436b's near-grazing transit geometry. …”
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The RAdial Velocity Experiment (RAVE): Fourth data release by Kordopatis, G, Gilmore, G, Steinmetz, M, Boeche, C, Seabroke, G, Siebert, A, Zwitter, T, Binney, J, Laverny, P, Recio-Blanco, A, Williams, M, Piffl, T, Enke, H, Roeser, S, Bijaoui, A, Wyse, R, Freeman, K, Munari, U, Carillo, I, Anguiano, B, Burton, D, Campbell, R, Cass, C, Fiegert, K, Hartley, M

“…The stellar atmospheric parameters are computed using a new pipeline, based on the algorithms of MATISSE and DEGAS. …”

Study of Compton broadening due to electron-photon scattering by Srinivasa Rao M.

“…We have investigated the effects of Compton broadening due to electron-photon scattering in hot stellar atmospheres. A purely electron-photon scattering media is assumed to have plane parallel geometry with an input radia­tion field localized on one side of the slab. …”
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Stark broadening parameter tables for neutral calcium spectral lines. I by Dimitrijević M.S., Sahal−Bréchot S.

“…Perturbers selected here, are the main perturbers in solar and stellar atmospheres.…”
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The R-Process Alliance: Spectroscopic Follow-up of Low-metallicity Star Candidates from the Best & Brightest Survey by Ezzeddine, Rana, Frebel, Anna L.

“…From medium-resolution (R ∼ 1200-2000) spectroscopy of 857 candidates, we estimate the stellar atmospheric parameters (Teff, log, g, and [Fe/H]), as well as carbon and α-element abundances. …”
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