Publications (56)
Characterizing Observed Extra Mixing Trends in Red Giants using the Reduced Density Ratio from Thermohaline Models
Adrian E. Fraser, Meridith Joyce, Evan H. Anders +2
Observations show an almost ubiquitous presence of extra mixing in low-mass upper giant branch stars. The most commonly invoked explanation for this is thermohaline mixing. One-dim…
Beyond MESA Defaults: The Impact of Structural Resolution Uncertainty in p-mode Asteroseismology
Yaguang Li, Meridith Joyce
Observations of pressure modes (-modes) in stars have enabled profound insights into stellar properties, and theoretical stellar evolution and oscillation models are integral to…
Gender Disparity in Publishing Six Months after the KITP Workshop "Probes of Transport in Stars"
Meridith Joyce, Jamie Tayar, Daniel Lecoanet
Conferences and workshops shape scientific discourse. The Kavli Institute for Theoretical Physics (KITP) hosts long-term workshops to stimulate scientific collaboration that would…
Not All Stars Are the Sun: Empirical Calibration of the Mixing Length for Metal-Poor Stars Using One-dimensional Stellar Evolution Models
Meridith Joyce, Brian Chaboyer
Theoretical stellar evolution models are constructed and tailored to the best known, observationally derived characteristics of metal-poor ([Fe/H]) stars representing a r…
The Milky Way Bulge Extra-Tidal Star Survey: NGC 6569
Joanne Hughes, Andrea Kunder, Kevin Covey +25
We present spectroscopic evidence for tidal debris associated with the bulge globular cluster NGC 6569, based on medium-resolution (R ~ 11,000) Anglo-Australian Telescope spectra o…
Betelgeuse, Betelgeuse, Betelgeuse, Betel-buddy? Constraints on the dynamical companion to Orionis from HST
Jared A. Goldberg, Anna J. G. O'Grady, Meridith Joyce +10
Recently, two independent analyses have asserted that the cause of the Long Secondary Period (LSP) observed in the variability spectrum of our nearest red supergiant, Betelgeuse ($…
The relationship between photometric and spectroscopic oscillation amplitudes from 3D stellar atmosphere simulations
Yixiao Zhou, Thomas Nordlander, Luca Casagrande +5
We establish a quantitative relationship between photometric and spectroscopic detections of solar-like oscillations using ab initio, three-dimensional (3D), hydrodynamical numeric…
A Buddy for Betelgeuse: Binarity as the Origin of the Long Secondary Period in Orionis
Jared A. Goldberg, Meridith Joyce, László Molnár
We predict the existence of Ori B, a low-mass companion orbiting Betelgeuse. This is motivated by the presence of a 2170-day Long Secondary Period (LSP) in Betelgeuse's lightc…
Convective Excitation and Damping of Solar-like Oscillations
Yixiao Zhou, Martin Asplund, Remo Collet +1
The last decade has seen a rapid development in asteroseismology thanks to the CoRoT and Kepler missions. With more detailed asteroseismic observations available, it is becoming po…
Bridging the Gap between Intermediate and Massive Stars II: for the most metal-rich stars and implications for Fe CCSNe rates
Giulia C. Cinquegrana, Meridith Joyce, Amanda I. Karakas
The minimum initial mass required for a star to explode as an Fe core collapse supernova, typically denoted , is an important quantity in stellar evolution because it…
Characterisation of 92 Southern TESS Candidate Planet Hosts and a New Photometric [Fe/H] Relation for Cool Dwarfs
Adam D. Rains, Maruša Žerjal, Michael J. Ireland +7
We present the results of a medium resolution optical spectroscopic survey of 92 cool (K) southern TESS candidate planet hosts, and des…
First results on RR Lyrae stars with the TESS space telescope: untangling the connections between mode content, colors and distances
László Molnár, Attila Bódi, András Pál +25
The TESS space telescope is collecting continuous, high-precision optical photometry of stars throughout the sky, including thousands of RR Lyrae stars. In this paper, we present r…
Star-crossed Clusters: Asteroseismic Ages for Individual Stars are in Tension with the Ages of their Host Clusters
Jamie Tayar, Meridith Joyce
A meta-analysis of seismic ages determined for individual stars in the well-studied open and globular clusters NGC 6819, NGC 6791, M67, M4, M19, M80, and M9 reveals both high varia…
C3PO: Towards a complete census of co-moving pairs of stars. I. High precision stellar parameters for 250 stars
David Yong, Fan Liu, Yuan-Sen Ting +6
We conduct a line-by-line differential analysis of a sample of 125 co-moving pairs of stars (dwarfs and subgiants near solar metallicity). We obtain high precision stellar paramete…
Asteroseismic sounding of bulge globular clusters with the Roman Space Telescope
László Molnár, Csilla Kalup, Meridith Joyce
Globular clusters are relics of the early Universe and they hold clues to many aspects of stellar and galactic evolution. We propose to point the Roman Space Telescope at one or mo…
A theoretical framework for BL Her stars -- II. New period-luminosity relations in the Gaia passbands
Susmita Das, László Molnár, Shashi M. Kanbur +6
We present new theoretical period-luminosity (PL) and period-Wesenheit (PW) relations for a fine grid of convective BL Her, the shortest period T2Cs, models computed using MESA-RSP…
The Blanco DECam Bulge Survey (BDBS) VIII: Chemo-kinematics in the southern Galactic bulge from 2.3 million red clump stars with Gaia DR3 proper motions
Tommaso Marchetti, Meridith Joyce, Christian Johnson +5
The Blanco DECam Bulge Survey (BDBS) provides near-ultraviolet to near-infrared photometry for ~250 million unique stars. By combining BDBS photometry with the latest Gaia astromet…
The GALAH survey: tracing the Galactic disk with Open Clusters
Lorenzo Spina, Yuan-Sen Ting, Gayandhi M. De Silva +28
Open clusters are unique tracers of the history of our own Galaxy's disk. According to our membership analysis based on \textit{Gaia} astrometry, out of the 226 potential clusters…
Betelgeuse's Buddy: X-Ray Constraints on the Nature of Ori B
Anna J. G. O'Grady, Brendan O'Connor, Jared A. Goldberg +8
The d Long Secondary Period of Betelgeuse's optical lightcurve and radial velocity motivated the prediction of a low-mass stellar companion, expected to be at maximal a…
Spinning up the Surface: Evidence for Planetary Engulfment or Unexpected Angular Momentum Transport?
Jamie Tayar, Facundo D. Moyano, Melinda Soares-Furtado +15
In this paper, we report the potential detection of a nonmonotonic radial rotation profile in a low-mass lower-luminosity giant star. For most low- and intermediate-mass stars, the…
Is Thermohaline Mixing the Full Story? Evidence for Separate Mixing Events near the Red Giant Branch Bump
Jamie Tayar, Meridith Joyce
The abundances of mixing--sensitive elements including lithium, [C/N], and 12C/13C are known to change near the red giant branch bump. The explanation most often offered for these…
Realistic Uncertainties for Fundamental Properties of Asteroseismic Red Giants and the Interplay Between Mixing Length, Metallicity and
Yaguang Li, Timothy R. Bedding, Daniel Huber +8
Asteroseismic modelling is a powerful way to derive stellar properties. However, the derived quantities are limited by built-in assumptions used in stellar models. This work presen…
Stellar Evolution in Real Time: Models Consistent with Direct Observation of Thermal Pulse in T Ursae Minoris
László Molnár, Meridith Joyce, László Kiss
Most aspects of stellar evolution proceed far too slowly to be directly observable in a single star on human timescales. The thermally pulsing asymptotic giant branch is one except…
TIC 308396022: a Scuti-- Doradus hybrid with large-amplitude radial fundamental mode and regular g-mode period spacing
Tao-Zhi Yang, Zhao-Yu Zuo, Gang Li +3
We analyse the pulsating behaviour of TIC 308396022 observed by the TESS mission. The star is a high-amplitude Sct star (HADS) that shows a very rich amplitude spectrum using…
Custom Colors: A Module for Computing Synthetic Photometry On-the-Fly in Stellar Evolution Calculations, Integrated with MESA and Usable with Other Stellar Evolution Codes
Niall Miller, Meridith Joyce, Philip Mocz
Stellar evolution simulations predict physical quantities such as luminosity, whereas broadband photometric observations measure flux in specific bandpasses; converting the predict…
A precise asteroseismic age and metallicity for HD 139614: a pre-main-sequence star with a protoplanetary disc in Upper-Centaurus Lupus
Simon J. Murphy, Meridith Joyce, Timothy R. Bedding +2
HD\,139614 is known to be a 14-Myr-old, possibly pre-main-sequence star in the Sco-Cen OB association in the Upper Centaurus-Lupus subgroup, with a slightly warped circumstel…
Standing on the shoulders of giants: New mass and distance estimates for Betelgeuse through combined evolutionary, asteroseismic, and hydrodynamical simulations with MESA
Meridith Joyce, Shing-Chi Leung, László Molnár +3
We conduct a rigorous examination of the nearby red supergiant Betelgeuse by drawing on the synthesis of new observational data and three different modeling techniques. Our observa…
The GALAH Survey: Chemical Clocks
Michael R. Hayden, Sanjib Sharma, Joss Bland-Hawthorn +27
Previous studies have found that the elemental abundances of a star correlate directly with its age and metallicity. Using this knowledge, we derive ages for a sample of 250,000 st…
The most metal-rich asymptotic giant branch stars
Amanda Karakas, Giulia Cinquegrana, Meridith Joyce
We present new stellar evolutionary sequences of very metal-rich stars evolved with the Monash Stellar Structure code and with MESA. The Monash models include masses of $1-8M_{\odo…
Density Conversion between 1-D and 3-D Stellar Models with 1D-MESA2HYDRO-3D
Meridith Joyce, Lianne Lairmore, Daniel J. Price +2
We present 1D-MESA2HYDRO-3D, an open source, Python-based software tool that provides an accessible means of generating physically motivated initial conditions (ICs) for hydrodynam…
The Two-infall Model Revisited: Constraints on Milky Way Bulge Assembly from >30,000 Galactic Chemical Evolution Models and Machine Learning
Niall Miller, Meridith Joyce, Christian I. Johnson +4
We constrain the formation history of the Milky Way bulge using a two-infall galactic chemical evolution (GCE) algorithm implemented in the N'OMEGA+ code. We recover a best-fit sce…
Modules for Experiments in Stellar Astrophysics (MESA): Time-Dependent Convection, Energy Conservation, Automatic Differentiation, and Infrastructure
Adam S. Jermyn, Evan B. Bauer, Josiah Schwab +19
We update the capabilities of the open-knowledge software instrument Modules for Experiments in Stellar Astrophysics (MESA). The new auto_diff module implements automatic different…
Stellar Models are Reliable at Low Metallicity: An Asteroseismic Age for the Ancient Very Metal-Poor Star KIC 8144907
Daniel Huber, Ditte Slumstrup, Marc Hon +15
Very metal-poor stars ([Fe/H]<-2) are important laboratories for testing stellar models and reconstructing the formation history of our galaxy. Asteroseismology is a powerful tool…
Blanco DECam Bulge Survey (BDBS) IV: Metallicity Distributions and Bulge Structure from 2.6 Million Red Clump Stars
Christian I. Johnson, R. Michael Rich, Iulia T. Simion +12
We present photometric metallicity measurements for a sample of 2.6 million bulge red clump stars extracted from the Blanco DECam Bulge Survey (BDBS). Similar to previous studies,…
At least one in a dozen stars exhibits evidence of planetary ingestion
Fan Liu, Yuan-Sen Ting, David Yong +6
Stellar chemical compositions can be altered by ingestion of planetary material and/or planet formation which removes refractory material from the proto-stellar disc. These "planet…
Blanco DECam Bulge Survey (BDBS) V. Cleaning the foreground populations from Galactic bulge colour-magnitude diagrams using Gaia EDR3
Tommaso Marchetti, Christian I. Johnson, Meridith Joyce +8
The Blanco DECam Bulge Survey (BDBS) has imaged more than 200 square degrees of the southern Galactic bulge, providing photometry in the ugrizy filters for million uniqu…
A theoretical framework for BL Her stars III. A case study: Robust light curve optimisation in the LMC
Susmita Das, László Molnár, Gábor B. Kovács +8
We carry out an extensive light curve comparison of BL Her stars using observations from Gaia DR3 and stellar pulsation models computed using MESA-RSP with the goal to obtain the b…
To Grow Old and Peculiar: A Survey of Anomalous Variable Stars in M80 and Age Determination using K2 and Gaia
László Molnár, Emese Plachy, Attila Bódi +11
The globular cluster Messier 80 was monitored by the Kepler space telescope for 80 days during the K2 mission. Continuous, high-precision photometry of such an old, compact cluster…
Stellar Evolution in Real Time II: R Hydrae and an Open-Source Grid of >3000 Seismic TP-AGB Models Computed with MESA
Meridith Joyce, László Molnár, Giulia Cinquegrana +3
We present a comprehensive characterization of the evolved thermally pulsing asymptotic giant branch (TP-AGB) star R Hydrae, building on the techniques applied in Stellar Evolution…
Bridging the Gap between Intermediate and Massive Stars I: Validation of MESA against the State-of-the-Art Monash Stellar Evolution Program for a 2 AGB Star
Giulia C. Cinquegrana, Meridith Joyce, Amanda I. Karakas
One--dimensional stellar structure and evolution programs are built using different physical prescriptions and algorithms, which means there can be variations between models' predi…
The Ages of Galactic Bulge Stars with Realistic Uncertainties
Meridith Joyce, Christian I. Johnson, Tommaso Marchetti +3
Using modern isochrones with customized physics and carefully considered statistical techniques, we recompute the age distribution for a sample of 91 micro-lensed dwarfs in the Gal…
Empirical Globular Cluster Ridgeline Construction on Gaia Data
Anett Simon-Zsók, László Molnár, Csilla Kalup +1
We present a new method and a corresponding code to compress the color magnitude diagram of a globular cluster into a representative curve, called a ridgeline, that can be more rea…
Suppressed phase variations in a high amplitude rapidly oscillating Ap star pulsating in a distorted quadrupole mode
Daniel L. Holdsworth, Hideyuki Saio, Dominic M. Bowman +5
We present the results of a multisite photometric observing campaign on the rapidly oscillating Ap (roAp) star 2MASS 16400299-0737293 (J1640; ). We analyse photometric …
RR Lyrae Stars Belonging to the Candidate Globular Cluster Patchick 99
Evan Butler, Andrea Kunder, Zdenek Prudil +16
Patchick 99 is a candidate globular cluster located in the direction of the Galactic bulge, with a proper motion almost identical to the field and extreme field star contamination.…
Discovery of post-mass-transfer helium-burning red giants using asteroseismology
Yaguang Li, Timothy R. Bedding, Simon J. Murphy +14
A star expands to become a red giant when it has fused all the hydrogen in its core into helium. If the star is in a binary system, its envelope can overflow onto its companion or…
A Review of the Mixing Length Theory of Convection in 1D Stellar Modeling
Meridith Joyce, Jamie Tayar
We review the application of the one-dimensional Mixing Length Theory (MLT) model of convection in stellar interiors and low-mass stellar evolution. We summarize the history of MLT…
Five young Scuti stars in the Pleiades seen with Kepler/K2
Simon J. Murphy, Timothy R. Bedding, Timothy R. White +4
We perform mode identification for five Scuti stars in the Pleiades star cluster, using custom light curves from K2 photometry. By creating échelle diagrams, we identify radi…
The Milky Way Bulge extra-tidal star survey: BH 261 (AL 3)
Andrea Kunder, Zdenek Prudil, Kevin Covey +19
The Milky Way Bulge extra-tidal star survey (MWBest) is a spectroscopic survey with the goal of identifying stripped globular cluster stars from inner Galaxy clusters. In this way,…
A grid of 200,000 models of young Scuti stars using MESA and GYRE
Simon J. Murphy, Timothy R. Bedding, Anuj Gautam +1
The rapidly increasing number of delta Scuti stars with regular patterns among their pulsation frequencies necessitates modelling tools to better understand the observations. Furth…
JWST Imaging of Earendel, the Extremely Magnified Star at Redshift
Brian Welch, Dan Coe, Erik Zackrisson +60
The gravitationally lensed star WHL0137-LS, nicknamed Earendel, was identified with a photometric redshift based on images taken with the Hubble Space Tele…
Matching seismic masses for RR Lyrae-type and oscillating red horizontal-branch stars in M4
László Molnár, Henryka Netzel, Madeline Howell +2
Globular clusters offer a powerful way to test the properties of stellar populations and the late stages of low-mass stellar evolution. In this paper we study oscillating giant sta…
A prescription for the asteroseismic surface correction
Yaguang Li, Timothy R. Bedding, Dennis Stello +11
In asteroseismology, the surface effect refers to a disparity between the observed and the modelled frequencies in stars with solar-like oscillations. It originates from improper m…
The K2 Galactic Archaeology Program Data Release 3: Age-abundance patterns in C1-C8 and C10-C18
Joel C. Zinn, Dennis Stello, Yvonne Elsworth +28
We present the third and final data release of the K2 Galactic Archaeology Program (K2 GAP) for Campaigns C1-C8 and C10-C18. We provide asteroseismic radius and mass coefficients,…
Comment on the feasibility of carbon burning in Betelgeuse: a response to "The evolutionary stage of Betelgeuse inferred from its pulsation periods," arXiv:2306.00287
László Molnár, Meridith Joyce, Shing-Chi Leung
The recent pre-print by Saio et al. 2023 argues that the supergiant Betelgeuse is already undergoing carbon burning, based on the assumption that all of its light variations are ca…
Solar calibration of using ÃSOPUS opacities in MESA
Giulia C Cinquegrana, Meridith Joyce
The simplistic but ubiquitous Mixing Length Theory (MLT) formalism is used to model convective energy transport within 1D stellar evolution calculations. The formalism relies on th…
Schwarzschild and Ledoux are equivalent on evolutionary timescales
Evan H. Anders, Adam S. Jermyn, Daniel Lecoanet +4
Stellar evolution models calculate convective boundaries using either the Schwarzschild or Ledoux criterion, but confusion remains regarding which criterion to use. Here we present…