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1. Palomar discovery and initial characterization of naked-eye long-period comet C/2022 E3 (ZTF)

   https://doi.org/10.1093/mnrasl/slad139  

   Bolin, B. T. ; Masci, F. J. ; Duev, D. A. ; Milburn, J. W. ; Neill, J. D. ; Purdum, J. N. ; Avdellidou, C. ; Saki, M. ; Cheng, Y-C ; Delbo, M. ; et al ( September 2023 , Monthly Notices of the Royal Astronomical Society: Letters)

   Long-period comets are planetesimal remnants constraining the environment and volatiles of the protoplanetary disc. We report the discovery of hyperbolic long-period comet C/2022 E3 Zwicky Transient Facility (ZTF), which has a perihelion ∼1.11 au, an eccentricity ≳1 and an inclination ∼109°, from images taken with the Palomar 48-inch telescope during morning twilight on 2022 March 2. Additionally, we report the characterization of C/2022 E3 (ZTF) from observations taken with the Palomar 200-inch, the Palomar 60-inch, and the NASA Infrared Telescope Facility in early 2023 February to 2023 March when the comet passed within ∼0.28 au of the Earth and reached a visible magnitude of ∼5. We measure g–r = 0.70 ± 0.01, r–i = 0.20 ± 0.01, i–z = 0.06 ± 0.01, z–J = 0.90 ± 0.01, J–H = 0.38 ± 0.01, and H–K = 0.15 ± 0.01 colours for the comet from observations. We measure the A(0°)fρ (0.8 μm) in a 6500 km radius from the nucleus of 1483 ± 40 cm, and CN, C3, and C2 production of 5.43 ± 0.11 × 1025, 2.01 ± 0.04 × 1024, and 3.08 ± 0.5 × 1025 mol s−1, similar to other long-period comets. We additionally observe the appearance of jet-like structures at a scale of ∼4000 km in wide-field g-band images, which may be caused by the presence of CN gas in the near-nucleus coma.

    

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2. A Mass–Magnitude Relation for Low-mass Stars Based on Dynamical Measurements of Thousands of Binary Star Systems

   https://doi.org/10.3847/1538-3881/ac8cf7  

   Giovinazzi, Mark R. ; Blake, Cullen H. ( September 2022 , The Astronomical Journal)

   Stellar mass is a fundamental parameter that is key to our understanding of stellar formation and evolution, as well as the characterization of nearby exoplanet companions. Historically, stellar masses have been derived from long-term observations of visual or spectroscopic binary star systems. While advances in high-resolution imaging have enabled observations of systems with shorter orbital periods, measurements of stellar masses remain challenging, and relatively few have been precisely measured. We present a new statistical approach to measuring masses for populations of stars. Using Gaia astrometry, we analyze the relative orbital motion of >3800 wide binary systems comprising low-mass stars to establish a mass–magnitude relation in the GaiaG_RPband spanning the absolute magnitude range 14.5 >$M_{G_{\mathrm{RP}}}$> 4.0, corresponding to a mass range of 0.08M_⊙≲M≲ 1.0M_⊙. This relation is directly applicable to >30 million stars in the Gaia catalog. Based on comparison to existing mass–magnitude relations calibrated forK_smagnitudes from the Two Micron All Sky Survey, we estimate that the internal precision of our mass estimates is ∼10%. We use this relation to estimate masses for a volume-limited sample of ∼18,200 stars within 50 pc of the Sun and the present-day field mass function for stars withM≲ 1.0M_⊙, which we find peaks at 0.16M_⊙. We investigate a volume-limited sample of wide binary systems with early-K dwarf primaries, complete for binary mass ratiosq> 0.2, and measure the distribution ofqat separations >100 au. We find that our distribution ofqis not uniform, rather decreasing towardq= 1.0.

    

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3. DFT Calculations for Mössbauer Properties on Dinuclear Center Models of the Resting Oxidized Cytochrome c Oxidase

   https://doi.org/10.1002/cphc.202100831  

   Han Du, Wen‐Ge ; Götz, Andreas W. ; Noodleman, Louis ( April 2022 , ChemPhysChem)

   Mössbauer isomer shift and quadrupole splitting properties have been calculated using the OLYP‐D3(BJ) density functional method on previously obtained (W.‐G. Han Du, et al.,Inorg Chem.2020,59, 8906–8915) geometry optimized Fe_a3³⁺−H₂O−Cu_B²⁺dinuclear center (DNC) clusters of the resting oxidized (Ostate) “as‐isolated” cytochromecoxidase (CcO). The calculated results are highly consistent with the available experimental observations. The calculations have also shown that the structural heterogeneities of theOstate DNCs implicated by the Mössbauer experiments are likely consequences of various factors, particularly the variable positions of the central H₂O molecule between the Fe_a3³⁺and Cu_B²⁺sites in different DNCs, whether or not this central H₂O molecule has H‐bonding interaction with another H₂O molecule, the different spin states having similar energies for the Fe_a3³⁺sites, and whether the Fe_a3³⁺and Cu_B²⁺sites are ferromagnetically or antiferromagnetically spin‐coupled.

    

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4. Six years of demography data for 11 reef coral species

   https://doi.org/10.1002/ecy.4017  

   Madin, Joshua S. ; Baird, Andrew H. ; Connolly, Sean R. ; Dornelas, Maria A. ; Álvarez‐Noriega, Mariana ; McWilliam, Michael J. ; Barbosa, Miguel ; Blowes, Shane A. ; Cetina‐Heredia, Paulina ; Christie, Alec P. ; et al ( March 2023 , Ecology)

   Scleractinian corals are colonial animals with a range of life‐history strategies, making up diverse species assemblages that define coral reefs. We tagged and tracked ~30 colonies from each of 11 species during seven trips spanning 6 years (2009–2015) to measure their vital rates and competitive interactions on the reef crest at Trimodal Reef, Lizard Island, Australia. Pairs of species were chosen from five growth forms in which one species of the pair was locally rare (R) and the other common (C). The sampled growth forms were massive (Goniastrea pectinata[R] andG. retiformis[C]), digitate (Acropora humilis[R] andA. cf.digitifera[C]), corymbose (A. millepora[R] andA. nasuta[C]), tabular (A. cytherea[R] andA. hyacinthus[C]) and arborescent (A. robusta[R] andA. intermedia[C]). An extra corymbose species with intermediate abundance,A. spathulatawas included when it became apparent thatA. milleporawas too rare on the reef crest, making the 11 species in total. The tagged colonies were visited each year in the weeks prior to spawning. During visits, two or more observers each took two or three photographs of each tagged colony from directly above and on the horizontal plane with a scale plate to track planar area. Dead or missing colonies were recorded and new colonies tagged to maintain ~30 colonies per species throughout the 6 years of the study. In addition to tracking tagged corals, 30 fragments were collected from neighboring untagged colonies of each species for counting numbers of eggs per polyp (fecundity); and fragments of untagged colonies were brought into the laboratory where spawned eggs were collected for biomass and energy measurements. We also conducted surveys at the study site to generate size structure data for each species in several of the years. Each tagged colony photograph was digitized by at least two people. Therefore, we could examine sources of error in planar area for both photographers and outliners. Competitive interactions were recorded for a subset of species by measuring the margins of tagged colony outlines interacting with neighboring corals. The study was abruptly ended by Tropical Cyclone Nathan (Category 4) that killed all but nine of the more than 300 tagged colonies in early 2015. Nonetheless, these data will be of use to other researchers interested in coral demography and coexistence, functional ecology, and parametrizing population, community, and ecosystem models. The data set is not copyright restricted, and users should cite this paper when using the data.

    

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5. Identification of Galaxy–Galaxy Strong Lens Candidates in the DECam Local Volume Exploration Survey Using Machine Learning

   https://doi.org/10.3847/1538-4357/ace4ba  

   Zaborowski, E. A. ; Drlica-Wagner, A. ; Ashmead, F. ; Wu, J. F. ; Morgan, R. ; Bom, C. R. ; Shajib, A. J. ; Birrer, S. ; Cerny, W. ; Buckley-Geer, E. J. ; et al ( August 2023 , The Astrophysical Journal)

   We perform a search for galaxy–galaxy strong lens systems using a convolutional neural network (CNN) applied to imaging data from the first public data release of the DECam Local Volume Exploration Survey, which contains ∼520 million astronomical sources covering ∼4000 deg²of the southern sky to a 5σpoint–source depth ofg= 24.3,r= 23.9,i= 23.3, andz= 22.8 mag. Following the methodology of similar searches using Dark Energy Camera data, we apply color and magnitude cuts to select a catalog of ∼11 million extended astronomical sources. After scoring with our CNN, the highest-scoring 50,000 images were visually inspected and assigned a score on a scale from 0 (not a lens) to 3 (very probable lens). We present a list of 581 strong lens candidates, 562 of which are previously unreported. We categorize our candidates using their human-assigned scores, resulting in 55 Grade A candidates, 149 Grade B candidates, and 377 Grade C candidates. We additionally highlight eight potential quadruply lensed quasars from this sample. Due to the location of our search footprint in the northern Galactic cap (b> 10 deg) and southern celestial hemisphere (decl. < 0 deg), our candidate list has little overlap with other existing ground-based searches. Where our search footprint does overlap with other searches, we find a significant number of high-quality candidates that were previously unidentified, indicating a degree of orthogonality in our methodology. We report properties of our candidates including apparent magnitude and Einstein radius estimated from the image separation.

    

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