Article
Astronomy & Astrophysics
Y. J. Aidelman, M. Borges Fernandes, L. S. Cidale, A. Smith Castelli, M. L. Arias, J. Zorec, M. Kraus, A. Torres, T. B. Souza, Y. R. Cochetti
Summary: The study used the BCD spectrophotometric classification system to observe stars exhibiting the B[e] phenomenon and LBVs, deriving their stellar parameters and physical properties. The results confirmed the classification of certain stars and determined the stellar parameters of LBVs for the first time. This highlights the importance and value of the BCD system for studying B-type stars in transition phases.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Gautham N. Sabhahit, Jorick S. Vink, Erin R. Higgins, Andreas A. C. Sander
Summary: Very massive stars play a dominant role in the physics of young clusters due to their ionizing radiation and extreme stellar winds. The temperature range of these stars is found to be narrow and influenced by metallicity. The study of mass loss and its effect on stellar temperature evolution reveals the importance of the luminosity-over-mass ratio and the Eddington parameter.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Gautham N. Sabhahit, Jorick S. Vink, Andreas A. C. Sander, Erin R. Higgins
Summary: Researchers utilize the transition mass-loss rate of Vink and Grafener (2012) to study the evolution of massive stars at high redshift. They find that above the transition mass, these stars evolve into low-luminosity pure helium stars, while below the transition mass, they evolve as cooler luminous blue variables or yellow hypergiants. This study is crucial for determining the threshold mass for pair-instability supernovae (PISNe) and modeling galactic chemical evolution.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
A. Soulain, A. Lamberts, F. Millour, P. Tuthill, R. M. Lau
Summary: A few binary Wolf-Rayet stars with spiral structures and high dust production rates provide a unique laboratory for studying dust nucleation in hostile environments. By simulating and observing, we obtained important parameters and properties of dust nucleation, and found that dust can escape beyond the boundaries of the spiral.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
A. C. Gormaz-Matamala, J. Cuadra, G. Meynet, M. Cure
Summary: In this study, the authors extend the previous mass-loss models by considering stellar rotation, CNO abundances, and He/H ratio. They generate a new set of evolutionary tracks and find that the mass-loss rate decreases with increasing surface helium content, which has a significant impact on more massive star models.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
W. L. F. Marcolino, J. C. Bouret, H. J. Rocha-Pinto, M. Bernini-Peron, J. S. Vink
Summary: This study explores the dependence of wind properties on metallicity and luminosity for O and B stars in the Milky Way and Small Magellanic Cloud, revealing a dependence in agreement with radiatively driven wind theory.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Asif ud-Doula, Stanley P. Owocki, Christopher Russell, Marc Gagne, Simon Daley-Yates
Summary: We present new self-consistent 3D magnetohydrodynamics simulations to study the magnetospheres of massive stars with an oblique dipole magnetic axis. Our results show that the accumulation surfaces in the magnetospheres resemble the forms predicted by the analytical rigidly rotating magnetosphere model, but the mass buildup distorts the magnetic field and warps the accumulation surface towards the rotational equator. This study provides a tool to synthesize rotational modulation of photometric absorption and Hα emission for comparison with observations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
I Araya, A. Christen, M. Cure, L. S. Cidale, R. O. J. Venero, C. Arcos, A. C. Gormaz-Matamala, M. Haucke, P. Escarate, H. Claveria
Summary: The research team proposed an analytical velocity profile description of massive star winds, established an approximate expression for the line force based on new parameters, and obtained mass loss rates through numerical calculations, establishing a relation with known line force parameters. Their findings showed good agreement between numerical and analytical calculations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
A. C. Gormaz-Matamala, M. Cure, G. Meynet, J. Cuadra, J. H. Groh, L. J. Murphy
Summary: This study presents a new method for predicting mass-loss rate in the evolutionary models of massive stars based on self-consistent calculations. The results show that the new method improves the prediction of mass loss compared to the traditional formulation. The study also identifies differences in stellar radius and mass when self-consistency is not used.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
C. Erba, A. David-Uraz, V Petit, L. Hennicker, C. Fletcher, A. W. Fullerton, Y. Naze, J. Sundqvist, A. Ud-Doula
Summary: Recent research has focused on the formation of UV resonance lines in slowly rotating magnetic massive stars with dynamical magnetospheres. These stars exhibit unique redshifted absorption features, and changes in line strength significantly affect the line profile shape.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
H. Neilson, N. Steenken, J. Simpson, R. Ignace, M. Shrestha, C. Erba, G. Henson
Summary: The semi-regular variable star V CVn is known for its unusual linear polarization position angle (PA). Despite variations in optical brightness and polarization amplitude, the constant PA has persisted over decades of observations. Our study reveals that the polarization maximum does not always coincide precisely with the brightness minimum, but instead exhibits a small lead or lag. Furthermore, the polarization position angle sometimes undergoes noticeable rotation, particularly at lower polarization levels. We find a correlation between this unusual optical behavior and high tangential space velocities, suggesting a relationship between the long-term constant PA and the shaping of circumstellar gas by the star's high-speed motion through the interstellar medium.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Peredur M. Williams, Watson P. Varricatt, Andre-Nicolas Chene, Michael F. Corcoran, Ted R. Gull, Kenji Hamaguchi, Anthony F. J. Moffat, Andrew M. T. Pollock, Noel D. Richardson, Christopher M. P. Russell, Andreas A. C. Sander, Ian R. Stevens, Gerd Weigelt
Summary: Spectroscopy of the P Cygni profile of the 1.083-μm He I line in the colliding-wind binary WR140 showed strong variations in both absorption and emission components. The absorption component varied significantly as the O5 star was occulted by the WCR, setting constraints on its geometry. The emission subpeak's radial velocity variation with orbital phase suggested formation in the WCR as it swung round the stars in their orbit.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
P. Jimenez-Hernandez, S. J. Arthur, J. A. Toala, A. P. Marston
Summary: The characterization of dust in the Wolf-Rayet nebula RCW58 around the WN8h star WR 40 was conducted using archival infrared and radio observations. It was found that there are two populations of dust grains with different sizes, and the nebula has a very high dust-to-gas ratio. Based on the model, RCW58 may have formed through a common envelope channel.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Jorick S. S. Vink, A. Mehner, P. A. Crowther, A. Fullerton, M. Garcia, F. Martins, N. Morrell, L. M. Oskinova, N. St-Louis, A. ud-Doula, A. A. C. Sander, H. Sana, J. -C. Bouret, B. Kubatova, P. Marchant, L. P. Martins, A. Wofford, J. Th. van Loon, O. Grace Telford, Y. Gotberg, D. M. Bowman, C. Erba, V. M. Kalari, M. Abdul-Masih, T. Alkousa, F. Backs, C. L. Barbosa, S. R. Berlanas, M. Bernini-Peron, J. M. Bestenlehner, R. Blomme, J. Bodensteiner, S. A. Brands, C. J. Evans, A. David-Uraz, F. A. Driessen, K. Dsilva, S. Geen, V. M. A. Gomez-Gonzalez, L. Grassitelli, W. -R. Hamann, C. Hawcroft, A. Herrero, E. R. Higgins, D. John Hillier, R. Ignace, A. G. Istrate, L. Kaper, N. D. Kee, C. Kehrig, Z. Keszthelyi, J. Klencki, A. de Koter, R. Kuiper, E. Laplace, C. J. K. Larkin, R. R. Lefever, C. Leitherer, D. J. Lennon, L. Mahy, J. Maiz Apellaniz, G. Maravelias, W. Marcolino, A. F. McLeod, S. E. de Mink, F. Najarro, M. S. Oey, T. N. Parsons, D. Pauli, M. G. Pedersen, R. K. Prinja, V. Ramachandran, M. C. Ramirez-Tannus, G. N. Sabhahit, A. Schootemeijer, S. Reyero Serantes, T. Shenar, G. S. Stringfellow, N. Sudnik, F. Tramper, L. Wang
Summary: Observations of various celestial events in the low-metallicity Universe indicate that it is different from our own Galaxy. Understanding the physics and evolution of massive stars at low metallicity is crucial for explaining many transient phenomena. The combination of UV and optical spectra obtained from the ULLYSES and XShootU projects is critical for accurately determining stellar parameters and wind properties, and will greatly contribute to astrophysical research.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
D. Badmaev, A. M. Bykov, M. E. Kalyashova
Summary: Young massive star clusters play a crucial role in galactic evolution and are potential cosmic ray accelerators. In this study, 3D magnetohydrodynamic modelling of a young compact cluster with multiple interacting supersonic winds is presented. The modelling reveals the presence of filamentary structures with high magnetic fields in the cluster core, suggesting the possibility of high-energy cosmic ray acceleration at this evolutionary stage.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
G-D Marleau, Y. Aoyama, R. Kuiper, K. Follette, N. J. Turner, G. Cugno, C. F. Manara, S. Y. Haffert, D. Kitzmann, S. C. Ringqvist, K. R. Wagner, R. van Boekel, S. Sallum, M. Janson, T. O. B. Schmidt, L. Venuti, Ch Lovis, C. Mordasini
Summary: This study calculates how gas and dust accreting onto a planet can reduce the Hα flux from the shock and affect the line shape. The research also investigates the absorption-modified relationship between Hα luminosity and accretion rate. The results show that extinction by the accreting matter is negligible in a wide range of parameter space, simplifying the interpretation of observations for planets in gaps.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
M. T. Beltran, V. M. Rivilla, R. Cesaroni, D. Galli, L. Moscadelli, A. Ahmadi, H. Beuther, S. Etoka, C. Goddi, P. D. Klaassen, R. Kuiper, M. S. N. Kumar, A. Lorenzani, T. Peters, A. Sanchez-Monge, P. Schilke, F. van der Tak, S. Vig
Summary: Observations of G31.41+0.31 reveal the simultaneous presence of inflow and outflow in all four embedded sources, indicating that they are still actively accreting and have not reached their final mass yet, confirming their youth.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
T. W. Moldenhauer, R. Kuiper, W. Kley, C. W. Ormel
Summary: This study investigates the efficiency of atmospheric recycling and its determining parameters using three-dimensional radiation-hydrodynamic simulations. It finds that atmospheric recycling is able to prevent the atmosphere from becoming self-gravitating and entering runaway gas accretion. The core mass and headwind have negligible effects on the recycling timescale, while the opacity has no significant effect. These findings suggest that atmosphere-disk recycling is the most natural explanation for the prevalence of close-in super-Earths and mini-Neptunes.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
C. Gieser, H. Beuther, D. Semenov, S. Suri, J. D. Soler, H. Linz, J. Syed, Th. Henning, S. Feng, T. Moeller, A. Palau, J. M. Winters, M. T. Beltran, R. Kuiper, L. Moscadelli, P. Klaassen, J. S. Urquhart, T. Peters, S. N. Longmore, A. Sanchez-Monge, R. Galvan-Madrid, R. E. Pudritz, K. G. Johnston
Summary: The study aims to characterize the physical and chemical properties of fragmented cores during the earliest evolutionary stages in very young star-forming regions. Results show that both regions contain a cluster of young stellar objects, and strong molecular emission is observed in some locations, which may be associated with bipolar outflows or colliding flows.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Eric Keto, Rolf Kuiper
Summary: Spherical Bondi accretion is an approximation used in astrophysics to study various accretion processes, and two-phase accretion flows can be stable, conditionally stable, or unstable during the transition from neutral to ionized states, depending on the initial conditions. The transition from an R-type to a D-type ionization front plays a crucial role in determining the stability of these flows.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Shyam H. Menon, Christoph Federrath, Mark R. Krumholz, Rolf Kuiper, Benjamin D. Wibking, Manuel Jung
Summary: VETTAM is a new algorithm for solving the equations of radiation hydrodynamics with support for adaptive mesh refinement. It effectively captures the behavior of radiation in various regimes and transitions, and produces accurate results.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Kohei Inayoshi, Riouhei Nakatani, Daisuke Toyouchi, Takashi Hosokawa, Rolf Kuiper, Masafusa Onoue
Summary: The study focuses on the early growth of massive seed black holes through accretion in protogalactic nuclei, showing a rapid accretion phase lasting around 2 million years. The findings suggest that seed BHs formed in massive dark-matter halos are more likely to end up as quasar hosts by z≈6. Such overmassive BHs can potentially be detected at z≈15 by upcoming observations with advanced telescopes.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Andre Oliva, Rolf Kuiper
Summary: This study aims to investigate in detail the mechanisms that drive highly collimated outflows from the early stages of massive star formation and how these processes are influenced by the properties of the natal environment. Using a series of simulations, we determined the impact of different environments on the morphology and momentum output of the outflows, and found that magnetic braking plays an important role in narrowing the outflow cavity. We also observed that despite the non-scalability of self-gravity and thermodynamics, our results scale with the mass of the cloud core and can be applied within a certain range of mass values.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Haojie Hu, Kohei Inayoshi, Zoltan Haiman, Wenxiu Li, Eliot Quataert, Rolf Kuiper
Summary: Observations of the most luminous quasars at high redshifts have shown that the largest supermassive black holes (SMBHs) tend to be significantly more massive relative to their host galaxies compared to what is observed locally, suggesting rapid early growth phases. Researchers propose an assembly model for these SMBHs that end up in massive host halos at high redshifts, incorporating a kinetic feedback prescription for black holes accreting at rates above the Eddington limit.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Andre Oliva, Rolf Kuiper
Summary: The physical mechanisms during the formation of massive protostars are found to have a significant impact on the appearance, size, and aspect ratio of circumstellar disks. The study reveals that magnetic pressure can slightly increase the size of the accretion disk, while magnetic braking plays a more significant role in the inner parts of the disk. Different initial conditions can produce similar disk sizes and protostellar masses.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Daisuke Toyouchi, Kohei Inayoshi, Wenxiu Li, Zoltan Haiman, Rolf Kuiper
Summary: Supermassive stars are proposed as possible seeds of high-redshift supermassive black holes, but it is still debated whether their protostars gain enough mass through gas accretion overcoming radiative feedback. We use three-dimensional radiation hydrodynamical simulations to investigate protostellar growth in dynamically heated atomic cooling haloes (ACHs) found in recent cosmological simulations, considering stellar evolution and variable mass accretion. We find that one ACH can feed the central protostar at rates that allow it to evolve unimpeded by radiative feedback, while another ACH with lower mass supply rate results in intense ionizing radiation and termination of stellar mass growth around 500 solar masses due to photoevaporation. Combining our results with statistical properties of star-forming clouds in high-redshift quasar progenitor haloes, we predict a top-heavy mass distribution of primordial stars and their black hole remnants fueling 'milliquasars' with high bolometric luminosity.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
R. Mignon-Risse, A. Oliva, M. Gonzalez, R. Kuiper, B. Commercon
Summary: In this study, the disk fragmentation in a centrally condensed protostellar system was compared using the RAMSES and PLUTO codes. The agreement between the two codes was good in terms of the formation of rotationally supported disk, accretion shock, and fragmentation phase. However, there were discrepancies in the dynamics of fragments, which were attributed to the different stellar accretion subgrid models used.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
D. Pauli, L. M. Oskinova, W. -R. Hamann, D. M. Bowman, H. Todt, T. Shenar, A. A. C. Sander, C. Erba, V. M. A. Gomez-Gonzalez, C. Kehrig, J. Klencki, R. Kuiper, A. Mehner, S. E. de Mink, M. S. Oey, V. Ramachandran, A. Schootemeijer, S. Reyero Serantes, A. Wofford
Summary: The origin of Wolf-Rayet (WR) stars in low-metallicity galaxies is not yet understood. This study analyzes the massive O star, AzV 14, to investigate the evolutionary paths from O-type to WR stage. The analysis shows that AzV 14 is a close binary system with two main sequence stars, and the binary evolutionary models can explain the observed parameters and predict the evolution into WR stars with different temperatures.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Yu Wang, Chris W. Ormel, Pinghui Huang, Rolf Kuiper
Summary: Planets with hot envelopes enriched by sublimation of volatile components from accreted pebbles exchange material with the disc, limiting the buildup of a vapour-rich atmosphere. This study uses hydrodynamical simulations to investigate how pebble sublimation influences the water content of super-Earths and sub-Neptunes. The extent and amount of vapour held by a planet is determined by the relative size of the sublimation front and the atmosphere. The introduced phase change module can also be used to model the chemical composition of gas in the vicinity of accreting planets and around snowlines in future studies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Gabriel-Dominique Marleau, Rolf Kuiper, William Bethune, Christoph Mordasini
Summary: This study reveals that the assumption of radial freefall for gas accretion onto gas giants is not accurate. By using multidimensional simulations, it is found that only about 1% of the gas inflow actually reaches the planet. This significantly affects the analysis of (non)detection statistics.
ASTROPHYSICAL JOURNAL
(2023)
