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1. Correction to: Conversions between gas-phase metallicities in MaNGA

   https://doi.org/10.1093/mnras/stae1765  

   Scudder, Jillian M; Ellison, Sara L; El Meddah El Idrissi, Loubna; Poetrodjojo, Henry (August 2024, Monthly Notices of the Royal Astronomical Society)

   A brief correction to a publication published in 2020, which created a 0.03 dex offset in published calibrations. 

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2. Metallicities from high-resolution spectra of 49 RR Lyrae variables

   https://doi.org/10.1093/mnras/stab857  

   Gilligan, Christina K; Chaboyer, Brian; Marengo, Massimo; Mullen, Joseph P; Bono, Giuseppe; Braga, Vittorio F; Crestani, Juliana; Dall’Ora, Massimo; Fiorentino, Giuliana; Monelli, Matteo; et al (April 2021, Monthly Notices of the Royal Astronomical Society)

   null (Ed.)

   ABSTRACT Accurate metallicities of RR Lyrae are extremely important in constraining period–luminosity–metallicity (PLZ) relationships, particularly in the near-infrared. We analyse 69 high-resolution spectra of Galactic RR Lyrae stars from the Southern African Large Telescope. We measure metallicities of 58 of these RR Lyrae stars with typical uncertainties of 0.15 dex. All but one RR Lyrae in this sample has accurate ($$\sigma _{\varpi }\lesssim 10{{\ \rm per\ cent}}$$) parallax from Gaia. Combining these new high-resolution spectroscopic abundances with similar determinations from the literature for 93 stars, we present new PLZ relationships in WISE W1 and W2 magnitudes, and the Wesenheit magnitudes W(W1, V − W1) and W(W2, V − W2). 

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3. Condensation at Varying Total Pressures and Metallicities: Rare Earth Elements

   Lodders, K.; Fegley, B. (July 2017, LPI Contribution No. 1987)

   Condensation of the ultrarefractory REE as oxides before Ca-bearing condensates at lower total pressures and [Fe/H] removes the need for removal of hibonite or perovskite from equilibrium with gas within an extremely small T interval after they become stable. 

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4. Improving White Dwarfs as Chronometers with Gaia Parallaxes and Spectroscopic Metallicities

   https://doi.org/10.3847/1538-4357/ac5ac0  

   Moss, Adam; von Hippel, Ted; Robinson, Elliot; El-Badry, Kareem; Stenning, David C.; van Dyk, David; Fouesneau, Morgan; Bailer-Jones, Coryn A. L.; Jeffery, Elizabeth; Sargent, Jimmy; et al (April 2022, The Astrophysical Journal)

   Abstract White dwarfs (WDs) offer unrealized potential in solving two problems in astrophysics: stellar age accuracy and precision. WD cooling ages can be inferred from surface temperatures and radii, which can be constrained with precision by high-quality photometry and parallaxes. Accurate and precise Gaia parallaxes along with photometric surveys provide information to derive cooling and total ages for vast numbers of WDs. Here we analyze 1372 WDs found in wide binaries with main-sequence (MS) companions and report on the cooling and total age precision attainable in these WD+MS systems. The total age of a WD can be further constrained if its original metallicity is known because the MS lifetime depends on metallicity at fixed mass, yet metallicity is unavailable via spectroscopy of the WD. We show that incorporating spectroscopic metallicity constraints from 38 wide binary MS companions substantially decreases internal uncertainties in WD total ages compared to a uniform constraint. Averaged over the 38 stars in our sample, the total (internal) age uncertainty improves from 21.04% to 16.77% when incorporating the spectroscopic constraint. Higher mass WDs yield better total age precision; for eight WDs with zero-age MS masses ≥2.0M_⊙, the mean uncertainty in total ages improves from 8.61% to 4.54% when incorporating spectroscopic metallicities. We find that it is often possible to achieve 5% total age precision for WDs with progenitor masses above 2.0M_⊙if parallaxes with ≤1% precision and Pan-STARRSg,r, andiphotometry with ≤0.01 mag precision are available. 

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5. Stellar Metallicities and Elemental Abundance Ratios of z~1.4 Massive Quiescent Galaxies

   https://doi.org/10.3847/2041-8213/ab2e75  

   Kriek, Mariska; Price, Sedona; Conroy, Charlie; Suess, Katherine; Mowla, Lamiya; Pasha, Imad; Bezanson, Rachel; van Dokkum, Pieter; Barro, Guillermo (August 2019, The astrophysical journal)

   The chemical composition of galaxies has been measured out to z∼4. However, nearly all studies beyond z∼0.7 are based on strong-line emission from HII regions within star-forming galaxies. Measuring the chemical composition of distant quiescent galaxies is extremely challenging, as the required stellar absorption features are faint and shifted to near-infrared wavelengths. Here, we present ultradeep rest-frame optical spectra of five massive quiescent galaxies at z∼1.4, all of which show numerous stellar absorption lines. We derive the abundance ratios [Mg/Fe] and [Fe/H] for three out of five galaxies; the remaining two galaxies have too young luminosity-weighted ages to yield robust measurements. Similar to lower-redshift findings, [Mg/Fe] appears positively correlated with stellar mass, while [Fe/H] is approximately constant with mass. These results may imply that the stellar mass–metallicity relation was already in place at z∼1.4. While the [Mg/Fe]−mass relation at z∼1.4 is consistent with the z<0.7 relation, [Fe/H] at z∼1.4 is ∼0.2 dex lower than at z<0.7. With a [Mg/Fe] of 0.44+0.08 the most -0.07 massive galaxy may be more α-enhanced than similar-mass galaxies at lower redshift, but the offset is less significant than the [Mg/Fe] of 0.6 previously found for a massive galaxy at z=2.1. Nonetheless, these results combined may suggest that [Mg/Fe] in the most massive galaxies decreases over time, possibly by accreting low- mass, less α-enhanced galaxies. A larger galaxy sample is needed to confirm this scenario. Finally, the abundance ratios indicate short star formation timescales of 0.2–1.0 Gyr. 

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