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The origin of magnetism around AGB stars is uncertain. If these stars drive a dynamo, it cannot be sufficient to generate a strong global field, otherwise the observed X-ray luminosities would be higher. Other explanations for the circular…

Astrophysics · Physics 2015-05-13 Helmut W. Wiesemeyer , Clemens Thum , Alain Baudry , Fabrice Herpin

We investigate the launching of outflows from the disk-magnetosphere boundary of slowly and rapidly rotating magnetized stars using axisymmetric and exploratory 3D magnetohydrodynamic (MHD) simulations. We find long-lasting outflows in both…

Solar and Stellar Astrophysics · Physics 2015-05-13 M. M. Romanova , G. V. Ustyugova , A. V. Koldoba , R. V. E. Lovelace

We report the detection of large variations in the outflow wind velocity from a young eruptive star, V899 Mon during its ongoing high accretion outburst phase. Such large variations in the outflow velocity (from -722 km s$^{-1}$ to -425 km…

Solar and Stellar Astrophysics · Physics 2016-07-06 J. P. Ninan , D. K. Ojha , N. S. Philip

We summarize recent 2D MHD simulations of line-driven stellar winds from rotating hot-stars with a dipole magnetic field aligned to the star's rotation axis. For moderate to strong fields, much wind outflow is initially along closed…

Astrophysics · Physics 2007-05-23 Stan Owocki , Asif ud-Doula

Jets, from the protostellar to the AGN context, have been extensively studied but their connection to the turbulent dynamics of the underlying accretion disc is poorly understood. Following a similar approach to Lesur et al. (2013), we…

High Energy Astrophysical Phenomena · Physics 2016-09-07 A. Riols , G. I. Ogilvie , H. Latter , J. P. Ross

We investigate how misalignment between the core angular momentum and the large-scale magnetic field affects protostellar outflows, and whether a single protostellar system can drive multiple outflow components. We perform three-dimensional…

Solar and Stellar Astrophysics · Physics 2026-04-24 Shingo Hirano , Yuri Aikawa , Masahiro N. Machida

To understand how planetary spin evolves and traces planet formation processes, we measure rotational line broadening in eight planetary-mass objects (PMOs) of various ages (1--800 Myr) using near-infrared high-resolution spectra from…

Earth and Planetary Astrophysics · Physics 2020-12-16 Marta L. Bryan , Sivan Ginzburg , Eugene Chiang , Caroline Morley , Brendan P. Bowler , Jerry W. Xuan , Heather A. Knutson

We discuss the star-disk electric circuit for a young stellar object (YSO) and calculate the expected torques on the star and the disk. We obtain the same disk magnetic field and star-disk torques as given by standard magnetohydrodynamic…

Astrophysics · Physics 2008-11-26 Kurt Liffman

We present milliarsecond-resolution maps of the SiO maser emission v=1 J=2-1 (3 mm) in the bipolar post-AGB nebula OH231.8+4.2, and compare them with our previous observations of the v=2 J=1-0 line (7 mm). Our observations show that the SiO…

Astrophysics · Physics 2007-05-23 J. F. Desmurs , C. Sanchez Contreras , V. Bujarrabal , J. Alcolea , F. Colomer

Jets and disc winds play an important role in the evolution of protoplanetary discs and the formation of planetary systems. However, there is still a lack of observational data regarding the presence and parameters of outflows, especially…

IRAS20126+4104 is a well studied B0.5 protostar that is surrounded by a ~1000 au Keplerian disk and is where a large-scale outflow originates. Both 6.7-GHz CH3OH masers and 22-GHz H2O masers have been detected toward this young stellar…

Solar and Stellar Astrophysics · Physics 2014-03-05 G. Surcis , W. H. T. Vlemmings , H. J. van Langevelde , L. Moscadelli , B. Hutawarakorn Kramer

H2O (22 GHz) and SiO masers (43, 86, 129 GHz) in the bipolar proto-planetary nebula OH231.8+4.2 were simultaneously monitored using the 21-m antennas of the Korean VLBI Network in 2009-2015. Both species exhibit periodic flux variations…

Solar and Stellar Astrophysics · Physics 2019-07-04 J. Kim , S. -H. Cho , V. Bujarrabal , H. Imai , R. Dodson , D. -H. Yoon , B. Zhang

We performed spectral line observations of CO J=2-1, 13CO J=1-0, and C18O J=1-0 and polarimetric observations in the 1.3 mm continuum and CO J=2-1 toward a multiple protostar system, L1448 IRS 3, in the Perseus molecular complex at a…

Astrophysics · Physics 2008-11-26 Woojin Kwon , Leslie W. Looney , Richard M. Crutcher , Jason M. Kirk

We present linear and circular polarization observations of the water masers in 4 distinct regions spread over 1x2 arcseconds around the HW2 high-mass young stellar object in the Cepheus A star-forming region. We find magnetic fields…

Astrophysics · Physics 2009-11-11 W. H. T. Vlemmings , P. J. Diamond , H. J. van Langevelde , J. M Torrelles

We present high resolution ($\sim$300 au) Atacama Large Millimeter/submillimeter Array (ALMA) observations of the massive young stellar object G11.92-0.61 MM 1. We resolve the immediate circumstellar environment of MM 1 in 1.3 mm continuum…

Solar and Stellar Astrophysics · Physics 2018-12-26 J. D. Ilee , C. J. Cyganowski , C. L. Brogan , T. R. Hunter , D. H. Forgan , T. J. Haworth , C. J. Clarke , T. J. Harries

We present the latest and final version of the movie of the SiO masers toward the Mira variable TX Cam. The new version consists of 112 frames (78 successfully reduced epochs) with data covering almost three complete stellar cycles between…

Solar and Stellar Astrophysics · Physics 2015-06-16 I. Gonidakis , P. J. Diamond , A. J. Kemball

We present the discovery of expanding spherical shells around low to intermediate-mass young stars in the Orion A giant molecular cloud using observations of $^{12}$CO (1-0) and $^{13}$CO (1-0) from the Nobeyama Radio Observatory 45-meter…

We carry out high resolution simulations of the inner regions of a wide angle wind driven bipolar outflow using an Adaptive Mesh Refinement code. Our code follows H-He gas with molecular, atomic and ionic components and the associated time…

Astrophysics · Physics 2009-11-11 Andrew Cunningham , Adam Frank , Lee Hartmann

SMA observations of the massive star-forming region IRAS 18089-1732 in the 1mm and 850mu band reveal outflow and disk signatures in different molecular lines. The SiO(5--4) data show a collimated outflow in the northern direction. In…

We performed SMA observations in the C18O (2-1) emission line toward six Class 0 and I protostars, to study rotational motions of their surrounding envelopes and circumstellar material on 100 to 1000 AU scales. C18O (2-1) emission with…

Solar and Stellar Astrophysics · Physics 2015-06-16 Hsi-Wei Yen , Shigehisa Takakuwa , Nagayoshi Ohashi , Paul T. P. Ho
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