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The maximum stellar surface density due to the failure of stellar feedback
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{"Abstract":["This file contains simple stellar population (SSP) model spectra constructed from a version of the SDSS-IV MaNGA Stellar Library (MaStar; Yan et al. 2019, Abdurro'uf et al. 2022) that has been corrected for the effects of absorption in the CaII 3934, 3969 and NaI D 5891, 5897 transitions arising in the Milky Way's interstellar medium (ISM). These corrections are described in full in Rubin et al. (2025), and our approach to constructing these SSP models is described in Maraston et al. (2020) and Rubin et al. (2025). In brief, our models are calculated with the evolutionary population synthesis code of Maraston (2005), which is based on the fuel consumption theorem for the evaluation of the energetics of post-Main Sequence phases. We use the calibrated median values of the stellar parameters calculated for the MaStar sample to generate representative stellar spectra as functions of effective temperature, surface gravity, and chemical composition. These representative spectra are then used as input for the stellar population models. The stellar parameter estimates are described in R. Yan et al. (2025, in preparation) and at https://www.sdss4.org/dr17/mastar/mastar-stellar-parameters/. \n\nWe calculate SSPs using stars in metallicity bins centered at [Z/H] = -1.35, -0.33, 0.0, and +0.35 with an approximate bin width of 0.1 dex assuming a Salpeter IMF. The SSP ages span 3 Myr to 15 Gyr and are calculated at 51 gridpoints. For comparison, we also calculate the equivalent SSPs using the uncorrected MaStar spectra. The datamodel is described below.\n\nHDU1: 51 x 4 x 1 x 3 matrix describing the parameters of each SSP spectrum. Each gridpoint (i,j,k) contains a 3-element array listing the age (in Gyr), metallicity, and IMF slope (in linear mass units)\n\nHDU2: 2 x 4563 array containing the vacuum wavelength and spectral resolution (R) grids for models constructed from the uncorrected (original) stellar library. The wavelength sampling is logarithmic and the wavelengths have units of Angstroms. R = wave / (FWHM dwave)\n\nHDU3: 51 x 4 x 1 x 4563 matrix containing the SSPs constructed from the uncorrected (original) stellar library in units of erg/s/Ang/Msun \n\nHDU4: 2 x 4542 array containing the vacuum wavelength and spectral resolution (R) grids for models constructed from the corrected (cleaned) stellar library. The wavelength sampling is logarithmic and the wavelengths have units of Angstroms. R = wave / (FWHM dwave)\n\nHDU5: 51 x 4 x 1 x 4542 matrix containing the SSPs constructed from the corrected (cleaned) stellar library in units of erg/s/Ang/Msun "],"Other":["Preferred Citation\n\nIf you use these model spectra in your research, we ask that you please cite our article, "Sloan Digital Sky Survey IV MaStar: Quantification and Abatement of Interstellar Absorption in the Largest Empirical Stellar Spectral Library," Rubin et al. (2025), ApJ, 981 31, doi:10.3847/1538-4357/ad8eb6. Please also cite this Zenodo deposit."]}more » « less
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ABSTRACT We measure rotational broadening in spectra taken by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey to characterize the relationship between stellar multiplicity and rotation. We create a sample of 2786 giants and 24 496 dwarfs with stellar parameters and multiple radial velocities from the APOGEE pipeline, projected rotation speeds vsin i determined from our own pipeline, and distances, masses, and ages measured by Sanders & Das. We use the statistical distribution of the maximum shift in the radial velocities, ΔRVmax, as a proxy for the close binary fraction to explore the interplay between stellar evolution, rotation, and multiplicity. Assuming that the minimum orbital period allowed is the critical period for Roche Lobe overflow and rotational synchronization, we calculate theoretical upper limits on expected vsin i and ΔRVmax values. These expectations agree with the positive correlation between the maximum ΔRVmax and vsin i values observed in our sample as a function of log(g). We find that the fast rotators in our sample have a high occurrence of short-period [log(P/d) ≲ 4] companions. We also find that old, rapidly rotating main-sequence stars have larger completeness-corrected close binary fractions than their younger peers. Furthermore, rapidly rotating stars with large ΔRVmax consistently show differences of 1–10 Gyr between the predicted gyrochronological and measured isochronal ages. These results point towards a link between rapid rotation and close binarity through tidal interactions. We conclude that stellar rotation is strongly correlated with stellar multiplicity in the field, and caution should be taken in the application of gyrochronology relations to cool stars.more » « less
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The Triangulum Extended (TREX) Survey: The Stellar Disk Dynamics of M33 as a Function of Stellar AgeAbstract Triangulum (M33) is a low-mass, relatively undisturbed spiral galaxy that offers a new regime in which to test models of dynamical heating. In spite of its proximity, M33's dynamical heating history has not yet been well-constrained. In this work, we present the TREX Survey, the largest stellar spectroscopic survey across the disk of M33. We present the stellar disk kinematics as a function of age to study the past and ongoing dynamical heating of M33. We measure line-of-sight velocities for ∼4500 disk stars. Using a subset, we divide the stars into broad age bins using Hubble Space Telescope and Canada–France–Hawaii Telescope photometric catalogs: massive main-sequence stars and helium-burning stars (∼80 Myr), intermediate-mass asymptotic branch stars (∼1 Gyr), and low-mass red giant branch stars (∼4 Gyr). We compare the stellar disk dynamics to that of the gas using existing Hi, CO, and Hαkinematics. We find that the disk of M33 has relatively low-velocity dispersion (∼16 km s−1), and unlike in the Milky Way and Andromeda galaxies, there is no strong trend in velocity dispersion as a function of stellar age. The youngest disk stars are as dynamically hot as the oldest disk stars and are dynamically hotter than predicted by most M33-like low-mass simulated analogs in Illustris. The velocity dispersion of the young stars is highly structured, with the large velocity dispersion fairly localized. The cause of this high-velocity dispersion is not evident from the observations and simulated analogs presented here.more » « less
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Abstract Energetic particles emitted by active stars are likely to propagate in astrospheric magnetized plasma and disrupted by the prior passage of energetic coronal mass ejections (CMEs). We carried out test-particle simulations of ∼GeV protons produced at a variety of distances from the M1Ve star AU Microscopii by coronal flares or traveling shocks. Particles are propagated within a large-scale quiescent three-dimensional magnetic field and stellar wind reconstructed from measured magnetograms, and within the same stellar environment following the passage of a 10 36 erg kinetic energy CME. In both cases, magnetic fluctuations with an isotropic power spectrum are overlayed onto the large-scale stellar magnetic field and particle propagation out to the two innnermost confirmed planets is examined. In the quiescent case, the magnetic field concentrates the particles into two regions near the ecliptic plane. After the passage of the CME, the closed field lines remain inflated and the reshuffled magnetic field remains highly compressed, shrinking the scattering mean free path of the particles. In the direction of propagation of the CME lobes the subsequent energetic particle (EP) flux is suppressed. Even for a CME front propagating out of the ecliptic plane, the EP flux along the planetary orbits highly fluctuates and peaks at ∼2–3 orders of magnitude higher than the average solar value at Earth, both in the quiescent and the post-CME cases.more » « less
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1093/mnras/sty3386
