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
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
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, 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
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
Noemi Roggero, Jerome Bouvier, Luisa M. Rebull, Ann Marie Cody
Summary: The study focuses on deriving the characteristics of dipper stars in Taurus by analyzing light curves of low-mass pre-main-sequence stars. The research finds a dipper occurrence of about 30% in disk-bearing stars observed with K2. Magnetospheric accretion is suggested as the main explanation for the observed light curves, but other mechanisms cannot be entirely ruled out.
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
J. Erkal, C. F. Manara, P. C. Schneider, M. Vincenzi, B. Nisini, D. Coffey, J. M. Alcala, D. Fedele, S. Antoniucci
Summary: The study used the He I λ0830 angstrom line to probe the material in the inner regions of protostellar disks in young stars from Lupus and Upper Scorpius, finding variations in profile types and line properties, indicating changes in accretion and outflow signatures over time and with source properties.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Suman Bhattacharyya, Blesson Mathew, Gourav Banerjee, R. Anusha, K. T. Paul, Sreeja S. Kartha
Summary: The study identified 98 rare stars transitioning from pre-main-sequence to main-sequence phase through photometric analysis, with the age and mass of 58 candidates determined. These transition phase candidates exhibit rotational velocity and color excess values between classical Be and Herbig Ae/Be stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
T. Steindl, K. Zwintz, D. M. Bowman
Summary: This study utilized PHOEBE to model the light curve of the eclipsing binary RS Cha, revealing evidence of tidally perturbed modes and confirming the presence of pulsation modes in RS Cha. The importance of amplitude modulation caused by changing light ratios in an eclipsing binary for mode identification was highlighted.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
S. Nidhi, Blesson Mathew, B. Shridharan, R. Arun, R. Anusha, Sreeja S. Kartha
Summary: In this study, we examined a sample of 119 Herbig Ae/Be stars in the Galactic anti-centre direction using spectroscopic data from the large sky area multi-object fiber spectroscopic telescope survey program. We identified emission lines of hydrogen and metallic lines of FeII, OI, CaII triplet. We also explored a technique for the extinction correction of these stars and estimated their stellar parameters and mass accretion rates.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
L. Gehrig, D. Steiner, E. Vorobyov, M. Guedel
Summary: The study aims to investigate the influence of hydrodynamic disk evolution on stellar rotational period and vice versa during the accretion phase. By combining the TAPIR disk code with a stellar spin evolution model, the research can reproduce the observed fast and slow rotating stars in young stellar clusters within a defined parameter space.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Devesh Nandal, John A. Regan, Tyrone E. Woods, Eoin Farrell, Sylvia Ekstrom, Georges Meynet
Summary: Efforts to understand the origin and growth of massive black holes observed in the early Universe have led to interest in the evolution and fate of rapidly accreting primordial stars. This study investigates the evolution of such stars under variable accretion rates, focusing on the thermal response, stellar structure, and the impact of accretion on their subsequent evolution. The findings reveal the critical accretion rate that determines the transition between red and blue supergiant phases, as well as the influence of the luminosity wave and variable accretion rates on the lifetimes and characteristics of these stars.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Gabriella Zsidi, Eleonora Fiorellino, Agnes Kospal, Peter Abraham, Attila Bodi, Gaitee Hussain, Carlo F. Manara, Andras Pal
Summary: This study investigates the accretion process, photometric, and spectroscopic variability of the classical T Tauri multiple system VW Cha. By analyzing TESS and ground-based observations, it is found that the TESS light curve shows photometric variations on timescales from minutes to weeks, and the near-infrared light curves follow the shape of the optical measurements with slightly increasing peak-to-peak amplitudes toward longer wavelengths. The brightening event is explained by increased accretion, and the spectroscopic data suggest that VW Cha is a spectroscopic binary.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
M. E. Shultz, E. Alecian, V Petit, S. Bagnulo, T. Bohm, C. P. Folsom, G. A. Wade
Summary: W 601 is a previously unreported spectroscopic binary, composed of two B2 stars with a mass ratio of 1.8. The star is not a classical Herbig Be star, but is likely on the pre-main sequence.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
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)
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. Albacete-Colombo, J. J. Drake, E. Flaccomio, N. J. Wright, V. Kashyap, M. G. Guarcello, K. Briggs, J. E. Drew, D. M. Fenech, G. Micela, M. Mccollough, R. K. Prinja, N. Schneider, S. Sciortino, J. S. Vink
Summary: This study investigates the diffuse X-ray emission in the nearby Cygnus OB2 stellar association and discovers large-scale diffuse X-ray emission. Through X-ray spectral analysis, the total X-ray luminosity and plasma temperature components of the diffuse X-ray emission are calculated. The diffuse X-ray emission coincides with low-extinction regions, likely caused by the interaction between stellar winds and the local interstellar medium.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
M. G. Guarcello, J. J. Drake, N. J. Wright, T. Naylor, E. Flaccomio, V. L. Kashyap, D. Garcia-Alvarez
Summary: The Cygnus OB2 association in the Cygnus X complex is the closest star-forming region to the Sun, hosting thousands of low-mass stars and up to 1000 OB stars. It is of great importance for modern astrophysics, and has been recently observed and combined with optical and infrared catalogs to create a combined catalog of 5703 sources.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
M. G. Guarcello, J. J. Drake, N. J. Wright, J. F. Albacete-Colombo, C. Clarke, B. Ercolano, E. Flaccomio, V. Kashyap, G. Micela, T. Naylor, N. Schneider, S. Sciortino, J. S. Vink
Summary: In our Galaxy, star formation occurs in various environments, including clusters hosting massive stars. This paper focuses on the nearby massive association Cyg OB2 and analyzes the correlation between the spatial variation of the disk fraction and local values of ultraviolet radiation fields and stellar surface density. The results show that disks are more rapidly dissipated in regions with intense UV fields and large stellar density, with FUV radiation dominating the dissipation timescales near the O stars.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
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)