Search Publications
Predicting the Spectrum of UGC 2885, Rubin's Galaxy with Machine Learning
Holwerda, Benne W.; Bailin, Jeremy; Böker, Torsten +10 more
Wu & Peek predict SDSS-quality spectra based on Pan-STARRS broadband grizy images using machine learning (ML). In this article, we test their prediction for a unique object, UGC 2885 ("Rubin's galaxy"), the largest and most massive, isolated disk galaxy in the local universe (D < 100 Mpc). After obtaining the ML predicted spectrum, we compa…
Mixed Modes and Asteroseismic Surface Effects. II. Subgiant Systematics
Bieryla, Allyson; Latham, David W.; Basu, Sarbani +3 more
Models of solar-like oscillators yield acoustic modes at different frequencies than would be seen in actual stars possessing identical interior structure, due to modeling error near the surface. This asteroseismic "surface term" must be corrected when mode frequencies are used to infer stellar structure. Subgiants exhibit oscillations of mixed aco…
Four Jovian planets around low-luminosity giant stars observed by the EXPRESS and PPPS
Jones, M. I.; Trifonov, T.; Soto, M. G. +14 more
We report the discovery of planetary companions orbiting four low-luminosity giant stars with M⋆ between 1.04 and 1.39 M⊙. All four host stars have been independently observed by the EXoPlanets aRound Evolved StarS (EXPRESS) program and the Pan-Pacific Planet Search (PPPS). The companion signals were revealed by multi-epoch p…
The impact of massive stars and black holes on the fate of open star clusters and their tidal streams
Wang, Long; Jerabkova, Tereza
Context. We use present-day observations to investigate how the content of massive OB stars affects the long-term evolution of young open clusters and their tidal streams, and how such an effect influences the constraint of initial conditions.
Aims: OB stars are typically found in binaries. They have a strong wind mass loss during the first f…
The Solar Neighborhood. XLVII. Comparing M-dwarf Models with Hubble Space Telescope Dynamical Masses and Spectroscopy
Henry, Todd J.; Jao, Wei-Chun; Dieterich, Serge B. +1 more
We use HST/STIS optical spectroscopy of 10 M dwarfs in five closely separated binary systems to test models of M-dwarf structure and evolution. Individual dynamical masses ranging from 0.083 to 0.405 M⊙ for all stars are known from previous work. We first derive temperature, radius, luminosity, surface gravity, and metallicity by fittin…
Lithium in red giants: the roles of the He-core flash and the luminosity bump
Lambert, David L.; Deepak
Lithium abundances for red giants in the GALAH DR3 survey are studied. The rare examples of Li-enriched stars with abundances A(Li) ≥1.5 are confirmed to be He-core burning stars belonging to or evolved from the red clump with similar masses and metallicity: M ≃ 1.1 ± 0.2 M⊙ and [Fe/H] ≃ -0.3 ± 0.3. Li enrichment over the Li abundance p…
UVES analysis of red giants in the bulge globular cluster NGC 6522
Chiappini, C.; Bica, E.; Barbuy, B. +10 more
Context. NGC 6522 is a moderately metal-poor bulge globular cluster ([Fe/H] ~ −1.0), and it is a well-studied representative among a number of moderately metal-poor blue horizontal branch clusters located in the bulge. The NGC 6522 abundance pattern can give hints on the earliest chemical enrichment in the central Galaxy.
Aims: The aim of thi…
A Distance-deviation Consistency and Model-independent Method to Test the Cosmic Distance-Duality Relation
Fang, Guanwen; Zhou, Chichun; Hu, Jian +2 more
A distance-deviation consistency and model-independent method to test the cosmic distance-duality relation (CDDR) is provided. This method is worthy of attention for two reasons. First, a distance-deviation consistency method is used to pair subsamples: instead of pairing subsamples with redshift deviations smaller than a value of, say, $\left|{\r…
S stars and s-process in the Gaia era. II. Constraining the luminosity of the third dredge-up with Tc-rich S stars
Van Winckel, Hans; Wallerstein, George; Plez, Bertrand +6 more
Context. S stars are late-type giants that are transition objects between M-type stars and carbon stars on the asymptotic giant branch (AGB). They are classified into two types: intrinsic or extrinsic, based on the presence or absence of technetium (Tc). The Tc-rich or intrinsic S stars are thermally pulsing (TP-)AGB stars internally producing s-p…
Is the orbit of the exoplanet WASP-43b really decaying? TESS and MuSCAT2 observations confirm no detection
Tamura, M.; Pallé, E.; Béjar, V. J. S. +24 more
Up to now, WASP-12b is the only hot Jupiter confirmed to have a decaying orbit. The case of WASP-43b is still under debate. Recent studies preferred or ruled out the orbital decay scenario, but further precise transit timing observations are needed to definitively confirm or refute the period change of WASP-43b. This possibility is given by the Tr…