Article
Astronomy & Astrophysics
K. Burdonov, W. Yao, A. Sladkov, R. Bonito, S. N. Chen, A. Ciardi, A. Korzhimanov, A. Soloviev, M. Starodubtsev, R. Zemskov, S. Orlando, M. Romanova, J. Fuchs
Summary: This study simulated the physical process of equatorial accretion and demonstrated that the laboratory results are consistent with the observations in astrophysical models. The findings support the possibility of equatorial accretion.
ASTRONOMY & ASTROPHYSICS
(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
A. Frasca, H. M. J. Boffin, C. F. Manara, J. M. Alcala, P. Abraham, E. Covino, M. Fang, M. Gangi, G. J. Herczeg, A. Kospal, L. Venuti, F. M. Walter, J. Alonso-Santiago, K. Grankin, M. Siwak, E. Alecian, S. Cabrit
Summary: In this study, the close pre-main sequence spectroscopic binary CVSO 104 in Ori OB1 was analyzed, revealing the orbital elements and stellar parameters of the system, as well as a significant infrared excess related to a circumbinary disk. Both components were found to be accreting at a similar level, with excess emission observed in Hα and Hβ possibly connected to accretion structures. The optical companion CVSO 104 B was identified as a background Sun-like star not physically associated with the PMS system.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
T. Steindl, K. Zwintz, T. G. Barnes, M. Muellner, E. Vorobyov
Summary: The study aims to constrain the physics of accretion on protostellar seeds by using observed spectroscopic parameters and stellar pulsations. It discovered several previously unknown pulsating pre-main-sequence stars, with evolutionary tracks showing that a mass accretion rate of 5 x 10(-6) M-circle dot yr(-1) provides the best results.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
D. Dmitriev, T. A. Ermolaeva, V. P. Grinin, I. S. Potravnov
Summary: During the burst of accretion activity observed in 2013, the accretion rate of RZ Psc increased significantly, indicating the instability of the accretion process during late stages of pre-main sequence evolution. By studying the magnetospheric emission in the H alpha line, we calculated the parameters of the magnetosphere and considered the recombination delay effect during gas motion in the stellar magnetosphere. The absence of magnetospheric absorption in the D Na I resonance lines allowed us to estimate a lower limit on the magnetosphere temperature and improve the precision of the accretion rate estimate. The best-fitting model suggests a logarithm of accretion rate of logM≈-10.1 +/- 0.3 (≈7x10-11 M⊙yr-1) and an inclination angle of RZ Psc of 43 degrees +/- 3 degrees, which is lower than the typical inclination angle for UX Ori stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
R. Mignon-Risse, M. Gonzalez, B. Commercon, J. Rosdahl
Summary: The study reveals that the environment with different turbulence intensities has an impact on the multiplicity of massive stars, and the interaction between magnetic fields and turbulence influences the multiplicity of stellar clusters.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
R. Carini, K. Biazzo, G. De Marchi, N. Panagia, G. Beccari, E. Brocato
Summary: In this study, the accretion properties of low-mass pre-main sequence stars in the LH 91 association within the Large Magellanic Clouds are investigated using optical multiband photometry obtained with the Hubble Space Telescope. The age distribution suggests a period of active star formation ranging from a few million years up to approximately 60 million years, with a gap between 5 million years and 10 million years. The masses of the pre-main sequence candidates range from 0.2 solar masses to 1.0 solar mass, with an average of approximately 0.80 solar mass. The results also show variations in accretion luminosity and mass accretion rate with the age of the stars. Comparison with LH 95 reveals that LH 91 appears to be in a more evolved stage. Additionally, the pre-main sequence candidates are found to be uniformly distributed without any evidence of clumps around more massive stars.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
K. Burdonov, R. Bonito, T. Giannini, N. Aidakina, C. Argiroffi, J. Beard, S. N. Chen, A. Ciardi, V. Ginzburg, K. Gubskiy, V. Gundorin, M. Gushchin, A. Kochetkov, S. Korobkov, A. Kuzmin, A. Kuznetsov, S. Pikuz, G. Revet, S. Ryazantsev, A. Shaykin, I. Shaykin, A. Soloviev, M. Starodubtsev, A. Strikovskiy, W. Yao, I. Yakovlev, R. Zemskov, I. Zudin, E. Khazanov, S. Orlando, J. Fuchs
Summary: The aim of the study is to investigate protostars known as EXor-type objects, using laboratory plasmas interacting with external magnetic fields to reveal the parameters of their accretion events. The experimental results support a scenario of additional matter accretion, suggesting the presence of a magnetic field of around 100 G in the accretion stream of EXor objects, located between the truncation radius and the stellar surface.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
T. Steindl, K. Zwintz, M. Muellner
Summary: This study investigates the asteroseismic modeling of pre-main-sequence delta Scuti stars and highlights the importance of including early stellar evolution physics in the calculations. The results show that insufficient input physics and imperfect modeling approaches lead to underestimated uncertainties and systematic errors in the extracted stellar parameters. A comparison between different modeling approaches suggests that a six-dimensional model with fixed accretion parameters is preferred over the previous ten-dimensional model. The modeling approach presented in this study can provide narrow constraints on the stellar parameters and has the potential to be applied in future research.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
A. Ratheesh, F. Tombesi, K. Fukumura, P. Soffitta, E. Costa, D. Kazanas
Summary: The study investigated the origin and geometry of the accretion disc wind in GRS 1915+105 using high-resolution spectroscopy, revealing a possible magnetic origin of the wind and a multiple ionisation component. The observed variability in the line flux between soft and hard states is most likely due to a large increase in the wind density, suggesting an intimate link between accretion and ejection processes in black hole binaries.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Jesse Weder, Christoph Mordasini, Alexandre Emsenhuber
Summary: This study investigates the evolution of large protoplanetary disc populations under the influence of magnetically driven disc winds, internal and external photoevaporation. The simulations show that both strong magnetic torques and weak magnetic winds are necessary to reproduce observed stellar accretion rates. The study also supports the importance of external photoevaporation in disc evolution and its potential influence on planetary formation.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Etienne Martel, Geoffroy Lesur
Summary: This study uses numerical simulations to propose that some transition discs (TDs) may be influenced by magnetised disc winds, which could explain their fast accretion and long-lived cavities. The simulations show that material in the cavity is accreted at sonic velocities, while the cavity itself rotates at a high speed due to magnetic braking.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
R. Mignon-Risse, M. Gonzalez, B. Commercon
Summary: The influence of magnetic fields on the formation of multiple massive stars, especially on the fragmentation modes and properties of multiple protostellar systems, is investigated. Simulation results show that magnetic fields reduce certain fragmentation modes and limit the growth of disks, which is important for understanding the mechanism of multiple massive star formation.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Jacob Cleaver, Lee Hartmann, Jaehan Bae
Summary: We investigate the role of the magnetorotational instability (MRI) in explaining the diverse range of observed accretion outbursts in protoplanetary discs. Our results suggest that short-lived, low accretion rate events are likely triggered in the inner disc and cannot be explained by MRI triggering through gravitational instability. By using time-dependent accretion disc models and comparing with observations, we find that the lag time between infrared and optical bursts in Gaia 17bpi can be explained by an outside-in propagation with an α > 0.1 in the MRI-active region. Our findings highlight the importance of near-infrared monitoring and call for more sophisticated simulations to better understand the observed phenomena.
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
L. Venuti, L. Prisinzano, G. G. Sacco, E. Flaccomio, R. Bonito, F. Damiani, G. Micela, M. G. Guarcello, S. Randich, J. R. Stauffer, A. M. Cody, R. D. Jeffries, S. H. P. Alencar, E. J. Alfaro, A. C. Lanzafame, E. Pancino, A. Bayo, G. Carraro, M. T. Costado, A. Frasca, P. Jofre, L. Morbidelli, S. G. Sousa, S. Zaggia
ASTRONOMY & ASTROPHYSICS
(2018)
Article
Astronomy & Astrophysics
C. A. Hill, C. P. Folsom, J. -F. Donati, G. J. Herczeg, G. A. J. Hussain, S. H. P. Alencar, S. G. Gregory
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2019)
Correction
Astronomy & Astrophysics
C. A. Hill, C. P. Folsom, J. -F. Donati, G. J. Herczeg, G. A. J. Hussain, S. H. P. Alencar, S. G. Gregory
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2019)
Article
Astronomy & Astrophysics
Alana P. Sousa, Silvia H. P. Alencar, Luisa M. Rebull, Catherine C. Espaillat, Nuria Calvet, Paula S. Teixeira
ASTRONOMY & ASTROPHYSICS
(2019)
Article
Astronomy & Astrophysics
C. Mendes de Oliveira, T. Ribeiro, W. Schoenell, A. Kanaan, R. A. Overzier, A. Molino, L. Sampedro, P. Coelho, C. E. Barbosa, A. Cortesi, M. Costa-Duarte, F. R. Herpich, J. A. Hernandez-Jimenez, V. M. Placco, H. S. Xavier, L. R. Abramo, R. K. Saito, A. L. Chies-Santos, A. Ederoclite, R. Lopes de Oliveira, D. R. Goncalves, S. Akras, L. A. Almeida, F. Almeida-Fernandes, T. C. Beers, C. Bonatto, S. Bonoli, E. S. Cypriano, E. Vinicius-Lima, R. S. de Souza, G. Fabiano de Souza, F. Ferrari, T. S. Goncalves, A. H. Gonzalez, L. A. Gutierrez-Soto, E. A. Hartmann, Y. Jaffe, L. O. Kerber, C. Lima-Dias, P. A. A. Lopes, K. Menendez-Delmestre, L. M. Nakazono, P. M. Novais, R. A. Ortega-Minakata, E. S. Pereira, H. D. Perottoni, C. Queiroz, R. R. R. Reis, W. A. Santos, T. Santos-Silva, R. M. Santucci, C. L. Barbosa, Beatriz B. Siffert, L. Sodre Jr, S. Torres-Flores, P. Westera, D. D. Whitten, J. S. Alcaniz, Javier Alonso-Garcia, S. Alencar, A. Alvarez-Candal, P. Amram, L. Azanha, R. H. Barba, P. H. Bernardinelli, M. Borges Fernandes, V Branco, D. Brito-Silva, M. L. Buzzo, J. Caffer, A. Campillay, Z. Cano, J. M. Carvano, M. Castejon, R. Cid Fernandes, M. L. L. Dantas, S. Daflon, G. Damke, R. de la Reza, L. J. de Melo de Azevedo, D. F. De Paula, K. G. Diem, R. Donnerstein, O. L. Dors, R. Dupke, S. Eikenberry, Carlos G. Escudero, Favio R. Faifer, H. Farias, B. Fernandes, C. Fernandes, S. Fontes, A. Galarza, N. S. T. Hirata, L. Katena, J. Gregorio-Hetem, J. D. Hernandez-Fernandez, L. Izzo, M. Jaque Arancibia, V Jatenco-Pereira, Y. Jimenez-Teja, D. A. Kann, A. C. Krabbe, C. Labayru, D. Lazzaro, G. B. Lima Neto, Amanda R. Lopes, R. Magalhaes, M. Makler, R. de Menezes, J. Miralda-Escude, R. Monteiro-Oliveira, A. D. Montero-Dorta, N. Munoz-Elgueta, R. S. Nemmen, J. L. Nilo Castellon, A. S. Oliveira, D. Ortiz, E. Pattaro, C. B. Pereira, B. Quint, L. Riguccini, H. J. Rocha Pinto, I Rodrigues, F. Roig, S. Rossi, Kanak Saha, R. Santos, A. Schnorr Mueller, Leandro A. Sesto, R. Silva, Analia Smith Castelli, R. Teixeira, E. Telles, R. C. Thom de Souza, C. Thone, M. Trevisan, A. de Ugarte Postigo, F. Urrutia-Viscarra, C. H. Veiga, M. Vika, A. Z. Vitorelli, A. Werle, S. Werner, D. Zaritsky
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2019)
Article
Astronomy & Astrophysics
J. F. Donati, J. Bouvier, S. H. Alencar, C. Moutou, L. Malo, M. Takami, F. Menard, C. Dougados, G. A. Hussain
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2020)
Article
Astronomy & Astrophysics
R. M. G. de Albuquerque, J. F. Gameiro, S. H. P. Alencar, J. J. G. Lima, C. Sauty, C. Melo
ASTRONOMY & ASTROPHYSICS
(2020)
Article
Astronomy & Astrophysics
T. Moura, S. H. P. Alencar, A. P. Sousa, E. Alecian, Y. Lebreton
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2020)
Article
Astronomy & Astrophysics
J. Roquette, S. H. P. Alencar, J. Bouvier, M. G. Guarcello, B. Reipurth
ASTRONOMY & ASTROPHYSICS
(2020)
Article
Astronomy & Astrophysics
J. Bouvier, E. Alecian, S. H. P. Alencar, A. Sousa, J. -F. Donati, K. Perraut, A. Bayo, L. M. Rebull, C. Dougados, G. Duvert, J. -P. Berger, M. Benisty, K. Pouilly, C. Folsom, C. Moutou
ASTRONOMY & ASTROPHYSICS
(2020)
Article
Astronomy & Astrophysics
K. Pouilly, J. Bouvier, E. Alecian, S. H. P. Alencar, A. -M. Cody, J. -F. Donati, K. Grankin, G. A. J. Hussain, L. Rebull, C. P. Folsom
ASTRONOMY & ASTROPHYSICS
(2020)
Article
Astronomy & Astrophysics
A. P. Sousa, J. Bouvier, S. H. P. Alencar, J. -F. Donati, E. Alecian, J. Roquette, K. Perraut, C. Dougados, A. Carmona, S. Covino, D. Fugazza, E. Molinari, C. Moutou, A. Santerne, K. Grankin, E. Artigau, X. Delfosse, G. Hebrard
Summary: The study focused on the dynamics of the young stellar system V2129 Oph, and found that the variations in optical and infrared line profiles are consistent with a magnetospheric accretion scenario.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
K. Pouilly, J. Bouvier, E. Alecian, S. H. P. Alencar, A-M Cody, J-F Donati, K. Grankin, L. Rebull, C. P. Folsom
Summary: Researchers study the magnetospheric accretion process in the young stellar object V807 Tau and observe periodic variations in the light curve, as well as changes in spectral features. Mapping the magnetic field topology at the surface, they find a tilted dipolar component and detect periodic accretion shock and funnel flow.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
B. Finociety, J-F Donati, B. Klein, B. Zaire, L. Lehmann, C. Moutou, J. Bouvier, S. H. P. Alencar, L. Yu, K. Grankin, E. Artigau, R. Doyon, X. Delfosse, P. Fouque, G. Hebrard, M. Jardine, A. Kospal, F. Menard
Summary: The results of spectropolarimetric and photometric monitoring of the weak-line T Tauri star V410 Tau provide information on the surface brightness and large-scale magnetic field, showing similarities to previous optical data but with some differences. The large-scale magnetic field is mainly poloidal and the surface differential rotation is slightly weaker than estimated in previous studies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
J. -F. Donati, J. Bouvier, S. H. Alencar, C. Hill, A. Carmona, C. P. Folsom, F. Menard, S. G. Gregory, G. A. Hussain, K. Grankin, C. Moutou, L. Malo, M. Takami, G. J. Herczeg
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2019)