Article
Astronomy & Astrophysics
L. Mahy, C. Lanthermann, D. Hutsemekers, J. Kluska, A. Lobel, R. Manick, B. Miszalski, M. Reggiani, H. Sana, E. Gosset
Summary: This article discusses the binary fraction and properties of Luminous blue variables (LBVs) in the Milky Way. Through spectroscopy and interferometry, a large binary fraction is detected, and possible formation mechanisms are proposed based on the analysis results.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
S. Ustamujic, S. Orlando, M. Miceli, F. Bocchino, M. Limongi, A. Chieffi, C. Trigilio, G. Umana, F. Bufano, A. Ingallinera, G. Peres
Summary: LBVs are massive evolved stars that suffer sporadic and violent mass-loss events. The study of SNRs from LBVs could help to place core-collapse SNe in context with the evolution of massive stars. The models show a common morphology of elongated ejecta with an internal jet-like structure for all LBV-like progenitors explored, indicating the importance of the CSM in determining the properties of the resulting SNR.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
O. Maryeva, S. Karpov, A. Y. Kniazev, V. V. Gvaramadze
Summary: In this paper, the long-term variability properties of the LBV candidate MN 112 are investigated. It is found that MN 112 is a dormant LBV that has been inactive for at least a century.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
J. R. Rizzo, C. Bordiu, C. Buemi, P. Leto, A. Ingallinera, F. Bufano, G. Umana, L. Cerrigone, C. Trigilio
Summary: This study investigates the molecular environment of the Galactic LBV star AFGL 2298. The results show the detection of carbon- and nitrogen-bearing species in the surroundings of AFGL 2298, with two components likely to have a stellar origin and one component potentially tracing interstellar material.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Nathan Smith, Jennifer E. Andrews, Alexei Filippenko, Ori D. Fox, Jon C. Mauerhan, Schuyler D. Van Dyk
Summary: New Hubble Space Telescope imaging data shows that the optical source at the site of the Type IIn supernova 2009ip has continued to fade steadily since the supernova-like event in 2012. The source is now fainter than its quiescent progenitor and previous outbursts, ruling out previous predictions that it would return to its previous state. The fading matches expectations for a terminal explosion, and there are no significant color changes or dust-obscured survivor indications. The late-time continuum and H alpha emission are consistent with shock interaction with circumstellar material. The ultraviolet flux has remained constant since 2015, supporting the idea that it traces OB stars in a young star cluster.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
L. Grassitelli, N. Langer, J. Mackey, G. Graefener, N. J. Grin, A. A. C. Sander, J. S. Vink
Summary: This study explores the impact of stellar wind mass-loss on envelope structure in massive stars near the Eddington limit, suggesting that when the wind mass-loss rate crosses a certain threshold, it leads to restructuring of the stellar envelope and induces drastic radius and temperature changes. The resulting cycle lacks a stationary equilibrium configuration and broadly reproduces the observational phenomenology of S Doradus variability.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Ashley Elliott, Noel D. Richardson, Herbert Pablo, Anthony F. J. Moffat, Dominic M. Bowman, Nour Ibrahim, Gerald Handler, Catherine Lovekin, Adam Popowicz, Nicole St-Louis, Gregg A. Wade, Konstanze Zwintz
Summary: LBVs are massive stars that may serve as a transitional phase between O stars and hydrogen-free Wolf-Rayet stars, with their variability showing evidence of being largely stochastic according to 5 years of photometry data collected by BRITE-Constellation nanosatellites for P Cygni. These results suggest that the variability of LBVs may be caused by internal gravity waves.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
C. Agliozzo, N. Phillips, A. Mehner, D. Baade, P. Scicluna, F. Kemper, D. Asmus, W-J de Wit, G. Pignata
Summary: By analyzing 31 LBVs, it was found that they may be a significant source of dust in Magellanic Clouds, with a relatively large dust mass that does not correlate with stellar parameters. LBVs are potentially the second most important source of dust in normal galaxies.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Juandre Light, S. E. S. Ferreira, N. E. Engelbrecht, K. Scherer, K. Herbst
Summary: Luminous blue variable-type stars, massive O-type stars, exhibit variable outflow parameters and eruptions. The astrospheres of these stars and the modulation of galactic cosmic rays are studied using a magnetohydrodynamic model and a 1D stochastic differential equation model. The results show that the variation in outflow parameters affects the number density up to the termination shock, and eruptions increase the size of the astrosphere.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Mojgan Aghakhanloo, Nathan Smith, Jennifer Andrews, Knut Olsen, Gurtina Besla, Yumi Choi
Summary: This study investigates the kinematics of LBVs in the LMC and finds that LBVs have a higher velocity dispersion and more runaway stars compared to red supergiants. It suggests that LBVs are preferentially kicked by a companion's supernova explosion. The study also discovers binary companions in some LBVs and identifies a new LBV.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Yakiv Pavlenko, Jonathan Tennyson, Sergei N. Yurchenko, Mirek R. Schmidt, Hugh R. A. Jones, Yuri Lyubchik, A. Suarez Mascareno
Summary: The recently computed ExoMol line lists for isotopologues of AlH are used to analyze the blue spectrum of Proxima Cen. By comparing the observed and computed spectra, researchers identified a large number of (AlH)-Al-27 lines. The study also reveals the characteristics of transitions close to the dissociation limit.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
L. S. Cidale, M. Haucke, M. L. Arias, M. Kraus, F. Campuzano Castro, R. O. J. Venero, L. Mercanti, M. Cure, A. Granada
Summary: The study focuses on the wind properties of B supergiants by analyzing their near-infrared (NIR) spectra. Variations in the mass-loss rate and spectral lines are observed, with some interesting features such as constraints set by the line profile shape and the presence of a circumstellar gas ring or shell.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
W. Bednarek
Summary: The study investigates strong dipole magnetic fields in early-type stars and their interaction with surface winds, suggesting that accelerated electrons in these regions may produce gamma-ray emissions. By predicting potential detection methods and variability based on calculations of specific star parameters, the research aims to test the scenario for gamma-ray emissions from single, luminous stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Noel D. Richardson, Olivier Thizy, Jon E. Bjorkman, Alex Carciofi, Amanda C. Rubio, Joshua D. Thomas, Karen S. Bjorkman, Jonathan Labadie-Bartz, Matheus Genaro, John P. Wisniewski, Luqian Wang, Douglas R. Gies, S. Drew Chojnowski, Andrea Daly, Thompson Edwards, Carlie Fowler, Allison D. Gullingsrud, Nolan Habel, David J. James, Emily Kehoe, Heidi Kuchta, Alexis Lane, Anatoly Miroshnichenko, Ashish Mishra, Herbert Pablo, Maurice Peploski, Joshua Pepper, Joseph E. Rodriguez, Robert J. Siverd, Keivan G. Stassun, Daniel J. Stevens, Jesica L. Trucks, James Windsor, Mackenna Wood, Etienne Bertrand, Jean-Jacques Broussat, Erik Bryssinck, Christian Buil, Stephane Charbonnel, Arnold de Bruin, Joe Daglen, Valerie Desnoux, James Dull, Olivier Garde, Keith Graham, Kevin Gurney, Alun Halsey, Patrik Fosanelli, Joan Guarro Flo, Franck Houpert, Foster James, Christian Kreider, Robin Leadbeater, Tim Lester, Dong Li, Alain Maetz, Albert Stiewing, Peter Somogyi, Jean-Noel Terry, Stephane Ubaud, Ulrich Waldschlaeger
Summary: The bright and understudied classical Be star HD 6226 has exhibited multiple outbursts and spectral properties, showing pulsational nature and relationship with mass ejection mechanism. Using a large dataset of spectroscopy, the dissipation time scales of H alpha and H beta lines were determined, laying the foundation for future observations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Ersilia Guarini, Irene Tamborra, Raffaella Margutti
Summary: Mounting evidence suggests that Luminous Fast Blue Optical Transients (LFBOTs) are powered by a compact object, launching an asymmetric and fast outflow responsible for the radiation observed in multiple bands. The production of neutrinos in these scenarios is also explored.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Matteo Cantiello, Adam S. Jermyn, Douglas N. C. Lin
Summary: AGN stars, embedded in extreme astrophysical environments, have different evolutionary conditions from normal stars, being strongly affected by mass accretion and loss, with chemical mixing playing a critical role in their evolution.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Adam S. Jermyn, Alexander J. Dittmann, Matteo Cantiello, Rosalba Perna
Summary: Stars in active galactic nuclei (AGN) can be formed or captured by accretion disks, experiencing extreme levels of accretion that can lead to their transformation into very massive stars. These AGN stars rapidly spin up due to accretion, maintaining near-critical rotation rates even as they evolve and shed their envelopes. They are considered potential sources of high-spin massive black holes and contribute to phenomena like long gamma-ray bursts and chemical pollution in AGN disks.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Alexander J. Dittmann, Matteo Cantiello, Adam S. Jermyn
Summary: Research indicates that stars formed in accretion disks around supermassive black holes exhibit significant differences in evolution compared to those in the interstellar medium, depending largely on the mass and distance of the black hole. Tidal effects from the black hole greatly impact the evolution of stars in AGN disks. The location of stellar explosions, formation of compact remnants, potential mergers producing gravitational waves, and different types of chemical enrichment in AGN disks are sensitive to the environmental conditions and parameters of the supermassive black hole.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Matteo Cantiello, Daniel Lecoanet, Adam S. Jermyn, Luca Grassitelli
Summary: High-precision photometric observations have revealed that stochastic low-frequency photometric variability in early-type stars is likely caused by subsurface convection. The presence of subsurface convection is closely related to the timescale and amplitude of this variability, as well as to the amplitude of macroturbulence. The explanation relying on convective core driven internal gravity waves encounters difficulties and seems unlikely to explain the observed trends.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Melinda Soares-Furtado, Matteo Cantiello, Morgan MacLeod, Melissa K. Ness
Summary: This study investigates the impact of hot Jupiter engulfment on surface Li enrichment using MESA stellar models and GALAH abundance measurements. The results show that engulfment of a hot Jupiter can lead to significant Li enrichment signatures in stars near the main-sequence turn-off.
ASTRONOMICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Adam S. Jermyn, Matteo Cantiello
Summary: Early-type stars exhibit a bimodal distribution of magnetic field strengths, which is related to the processing or lack thereof of fossil fields by subsurface convection zones. Stars that process weak fossil fields at the surface generate even weaker dynamo-generated fields, while stars with stronger fossil fields have magnetism that inhibits convection, allowing the fossil field to remain unchanged. This explains the slow evolution of magnetism in stars with very weak fields, as surface magnetism reflects the frozen-in remains of the convective dynamo, evolving on the timescale of mass loss rather than the dynamo itself.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Adam S. Jermyn, Alexander J. Dittmann, B. McKernan, K. E. S. Ford, Matteo Cantiello
Summary: Stars embedded in the gas disks of AGN can significantly impact the disk chemistry and structure. Their mergers can result in mass loss and even lead to binary black hole mergers.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Adam S. Jermyn, Evan H. Anders, Daniel Lecoanet, Matteo Cantiello
Summary: Observations indicate that convective cores of stars ingest material from the overlying radiative zone. The mechanism causing this mixing is uncertain. By using a theory of convective penetration, it is found that convective penetration can explain the core masses of stars and matches observed trends in mass and age. The results suggest that most convective boundary mixing in early-type main-sequence stars arises from convective penetration.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Adam S. Jermyn, Evan H. Anders, Matteo Cantiello
Summary: Subsurface convection zones are common in early-type stars but not present in all stars. Stability windows exist for different metallicity levels where no subsurface convection zones are present. This is important for studying the surface properties and photometric variability of stars.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Eoin Farrell, Adam S. Jermyn, Matteo Cantiello, Daniel Foreman-Mackey
Summary: This study combines observations and theoretical models to infer the initial distribution of magnetic fields for AB stars in the mass range of 1.6-3.4 M (circle dot). The most favored distribution is found to have a mean of 770 G and a standard deviation of 146 G, indicating a potential discrepancy in the typical field strength and suggesting a mass-dependent and bimodal initial field distribution or an alternative theoretical picture for the origin of these magnetic fields.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Adam S. Jermyn, Evan H. Anders, Daniel Lecoanet, Matteo Cantiello
Summary: Convection in main-sequence stars shows immense diversity under different conditions, with efficient or inefficient, rotationally constrained or not, and transsonic or deeply subsonic characteristics. This exploration serves as a guide for future theoretical and observational investigations.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2022)
Article
Astronomy & Astrophysics
Adrian E. Fraser, Meridith Joyce, Evan H. Anders, Jamie Tayar, Matteo Cantiello
Summary: The observed amount of extra mixing is strongly correlated with the reduced density ratio, and trends between the reduced density ratio and fundamental stellar parameters are robust across choices for modeling prescription. Increased mixing at low reduced density ratios is consistent with current hydrodynamical models of thermohaline mixing.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
M. Renzo, E. Zapartas, S. Justham, K. Breivik, M. Lau, R. Farmer, M. Cantiello, B. D. Metzger
Summary: Common envelope (CE) evolution plays a critical role in the formation of compact binaries, including gravitational-wave sources. The rejuvenation of the accretor star during the first stable mass transfer decreases the energy required to eject a CE by a significant amount. This finding suggests that binaries experiencing first stable mass transfer may have wider final separations than currently predicted.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Christopher E. O'Connor, Lars Bildsten, Matteo Cantiello, Dong Lai
Summary: About 10% of Sun-like stars will swallow a planet with a mass of 1-10 Jupiter masses during their evolution as red giants or asymptotic giants. Once engulfed, these planets spiral inward, depositing energy and angular momentum in the star's convective envelope. Different responses from the star and changes in asteroseismic indicators can be observed before and after the engulfment. Engulfment of massive planets on the asymptotic giant branch can cause a bright, red, dusty eruption similar to a luminous red nova. These events could be a significant fraction of low-luminosity red novae in the Galaxy. Conditions where the envelope is ejected prior to the planet's tidal disruption are not found.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Alexander J. Dittmann, Adam S. Jermyn, Matteo Cantiello
Summary: This study explores the impact of the helium abundance in active galactic nuclei (AGN) disks on the evolution of embedded stars. It is found that higher helium mass fractions in the disks lead to more luminous stars and increased radiation-driven mass loss. Additionally, disks with higher helium mass fractions tend to have less massive embedded stars and are less likely to host immortal stars. These findings suggest that disk composition can affect electromagnetic and gravitational wave transients, as well as chemical enrichment by embedded stars.
ASTROPHYSICAL JOURNAL
(2023)