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The Metallicity Variations Along the Chromosome Maps: The Globular Cluster 47 Tucanae
Milone, A. P.; Cordoni, G.; Marino, A. F. +11 more
The "chromosome maps" (ChMs) of globular clusters (GCs) have revealed that these ancient structures are inhomogeneous in metallicity in various ways and in different natures. Type II GCs generally display larger variations, sometimes coupled with slow neutron-capture (s) element enrichments on the ChMs redder sequences, which have been interpreted…
Stellar classification with convolutional neural networks and photometric images: a new catalogue of 50 million SDSS stars without spectra
Luo, A. -Li; Kong, Xiao; Shi, Jing-Hang +3 more
Stellar classification is a central topic in astronomical research that relies mostly on the use of spectra. However, with the development of large sky surveys, spectra are becoming increasingly scarce compared to photometric images. Numerous observed stars lack spectral types. In Sloan Digital Sky Survey (SDSS), there are more than hundreds of mi…
Exploring the variability of the venusian thermosphere with the IPSL Venus GCM
Lefèvre, Franck; Lebonnois, Sébastien; Millour, Ehouarn +4 more
Recent simulations of the Institut Pierre-Simon Laplace (IPSL) Venus Global Climate Model (VGCM) developed at the Laboratoire de Météorologie Dynamique (LMD) were performed with a model top raised from ∼10-5 (∼150 km) to ∼10-8 Pa (180-250 km; upper boundary). The parameterizations of non-LTE CO2 near infrared heati…
JWST Observations of the Enigmatic Y-Dwarf WISE 1828+2650. I. Limits to a Binary Companion
Johnstone, Doug; Leisenring, Jarron; Rieke, George +20 more
The Y-dwarf WISE 1828+2650 is one of the coldest known brown dwarfs with an effective temperature of ~300 K. Located at a distance of just 10 pc, previous model-based estimates suggest WISE1828+2650 has a mass of ~5-10 M J, making it a valuable laboratory for understanding the formation, evolution, and physical characteristics of gas gi…
Stellar Populations in the Central 0.5 pc of Our Galaxy. III. The Dynamical Substructures
Lu, Jessica R.; Ghez, A. M.; Morris, M. R. +12 more
We measure the 3D kinematic structures of the young stars within the central 0.5 pc of our Galactic Center using the 10 m telescopes of the W. M. Keck Observatory over a time span of 25 yr. Using high-precision measurements of positions on the sky and proper motions and radial velocities from new observations and the literature, we constrain the o…
Classifying Globular Clusters and Applying them to Estimate the mass of the Milky Way
Gao, Qi; Liu, Chao; Chen, Xuelei +3 more
We combine the kinematics of 159 globular clusters (GCs) provided by the Gaia Early Data Release 3 (EDR3) with other observational data to classify the GCs, and to estimate the mass of the Milky Way (MW). We use the age-metallicity relation, integrals of motion, action space and the GC orbits to identify the GCs as either formed in situ (Bulge and…
Spirals and Clumps in V960 Mon: Signs of Planet Formation via Gravitational Instability around an FU Ori Star?
Takami, Michihiro; Kóspál, Ágnes; Garufi, Antonio +11 more
The formation of giant planets has traditionally been divided into two pathways: core accretion and gravitational instability. However, in recent years, gravitational instability has become less favored, primarily due to the scarcity of observations of fragmented protoplanetary disks around young stars and the low occurrence rate of massive planet…
Evolution of Magnetic Field Fluctuations and Their Spectral Properties within the Heliosphere: Statistical Approach
Verscharen, Daniel; Bale, Stuart D.; Horbury, Timothy S. +4 more
We present the first comprehensive statistical study of the evolution of compressive and noncompressive magnetic field fluctuations in the inner heliosphere. Based on Parker Solar Probe (PSP) and Solar Orbiter data at various distances from the Sun, we show the general trends and compare them with Wind observations near 1 au. The paper analyzes so…
A Study of Twelve Potential Merger Candidate Contact Binary Systems
Filipović, Miroslav D.; Wadhwa, Surjit S.; Tothill, Nick F. H. +4 more
Photometric observations and analysis of twelve previously poorly studied contact binary systems is presented. All show total eclipses and have extremely low mass ratios ranging from 0.072 to 0.15. Also, all show characteristics of orbital instability with mass ratios within the theoretical orbital instability range. Although none demonstrate a si…
Spectroscopic follow-up of black hole and neutron star candidates in ellipsoidal variables from Gaia DR3
El-Badry, Kareem; Nagarajan, Pranav; Rodriguez, Antonio C. +2 more
We present multi-epoch spectroscopic follow-up of a sample of ellipsoidal variables selected from Gaia Data Release 3 (DR3) as candidates for hosting quiescent black holes (BHs) and neutron stars (NSs). Our targets were identified as BH/NS candidates because their optical light curves - when interpreted with models that attribute variability to ti…