scholarly journals EMISSA (Exploring Millimeter Indicators of Solar-Stellar Activity). I. The initial millimeter - centimeter main-sequence star sample

2021 ◽  
Author(s):  
A. Mohan ◽  
S. Wedemeyer ◽  
S. Pandit ◽  
M. Saberi ◽  
P. H. Hauschildt
Keyword(s):  
Main Sequence ◽  
Main Sequence Star ◽  
Stellar Activity

A large rotating structure around AB Doradus A at VLBI scale

2019 ◽  
Vol 15 (S354) ◽  
pp. 189-194
Author(s):  
J. B. Climent ◽  
J. C. Guirado ◽  
R. Azulay ◽  
J. M. Marcaide
Keyword(s):  
Magnetic Reconnection ◽  
Main Sequence ◽  
Complex Structure ◽  
Main Sequence Star ◽  
Polar Cap ◽  
Vlbi Observations ◽  
Rotating Structure ◽  
Source Structure ◽  
Expected Position

AbstractWe report the results of three VLBI observations of the pre-main-sequence star AB Doradus A at 8.4 GHz. With almost three years between consecutive observations, we found a complex structure at the expected position of this star for all epochs. Maps at epochs 2007 and 2010 show a double core-halo morphology while the 2013 map reveals three emission peaks with separations between 5 and 18 stellar radii. Furthermore, all maps show a clear variation of the source structure within the observing time. We consider a number of hypothesis in order to explain such observations, mainly: magnetic reconnection in loops on the polar cap, a more general loop scenario and a close companion to AB Dor A.

scholarly journals PHIBSS: MOLECULAR GAS CONTENT AND SCALING RELATIONS INz∼ 1-3 MASSIVE, MAIN-SEQUENCE STAR-FORMING GALAXIES

2013 ◽  
Vol 768 (1) ◽  
pp. 74 ◽  
Author(s):  
L. J. Tacconi ◽  
R. Neri ◽  
R. Genzel ◽  
F. Combes ◽  
A. Bolatto ◽  
...  
Keyword(s):  
Main Sequence ◽  
Gas Content ◽  
Main Sequence Star ◽  
Scaling Relations ◽  
Molecular Gas ◽  
Star Forming

scholarly journals The habitable zone of Kepler-16: impact of binarity and climate models

2018 ◽  
Vol 18 (1) ◽  
pp. 79-89 ◽  
Author(s):  
S. Y. Moorman ◽  
B. L. Quarles ◽  
Zh. Wang ◽  
M. Cuntz
Keyword(s):  
Binary System ◽  
Main Sequence ◽  
Climate Models ◽  
Main Sequence Star ◽  
Habitable Zone ◽  
Lagrangian Points ◽  
The Earth ◽  
Stable Solutions

AbstractWe continue to investigate the binary system Kepler-16, consisting of a K-type main-sequence star, a red dwarf and a circumbinary Saturnian planet. As part of our study, we describe the system's habitable zone based on different climate models. We also report on stability investigations for possible Earth-mass Trojans while expanding a previous study by B. L. Quarles and collaborators given in 2012. For the climate models, we carefully consider the relevance of the system's parameters. Furthermore, we pursue new stability simulations for the Earth-mass objects starting along the orbit of Kepler-16b. The eccentricity distribution as obtained prefers values close to circular, whereas the inclination distribution remains flat. The stable solutions are distributed near the co-orbital Lagrangian points, thus enhancing the plausibility that Earth-mass Trojans might be able to exist in the Kepler-16(AB) system.

scholarly journals New Results on the Binary Companion of T Tauri

1983 ◽  
Vol 71 ◽  
pp. 505-507 ◽  
Author(s):  
Theodore Simon ◽  
P.R. Schwartz ◽  
H.M. Dyck ◽  
B. Zuckerman
Keyword(s):  
Main Sequence ◽  
Position Angle ◽  
Speckle Interferometry ◽  
Main Sequence Star ◽  
Near Ir ◽  
T Tauri ◽  
Optical Star ◽  
T Tau

We have recently reported the discovery of a cool (650–800 K) low-luminosity companion to the pre-main-sequence star, T Tauri (Dyck et al. 1982). We proposed that the optical star and its infrared companion form a physical pair with a N-S separation of 100 a.u. However, there remained in our 2-5 μm speckle interferometry an ambiguity of 180° in the position angle of the secondary. In addition, Cohen et al. (1982) noted an 800 milliarcsec (mas) offset between the visual and 6 cm radio positions at T Tau. Both of these positional discrepancies have now been clarified by accurate visual and radio astrometry of T Tau, and by further near-IR speckle interferometry.

scholarly journals Photometric Study of two Southern Algol Type Binaries

1989 ◽  
Vol 107 ◽  
pp. 376-376
Author(s):  
K. D. Abhyankar ◽  
M. L. Vyas
Keyword(s):  
Spectroscopic Data ◽  
Main Sequence ◽  
Light Curves ◽  
The Other ◽  
Main Sequence Star ◽  
Photometric Study ◽  
The Absolute ◽  
Better Than ◽  
Absolute Dimensions

Complete UBV light-curves of RR-Lep and RX-Hya have been obtained during 1983-87 seasons. Preliminary elements were computed using modified Wellmann’s method. With these parameters as inputs Wilson-Devinney program was executed for Blue and Yellow passbands simultaneously in detached and semi-detached modes for both the systems. The semidetached mode fitted better than the other solution for both the systems. For RR-Lep, the absolute dimensions were computed by assuming the primary to be a slightly evolved main sequence star. For RX-Hya, the absolute dimensions were computed using Struve’s spectroscopic data. The following table gives all the elements for both the systems. The secondaries of both the systems are overluminous for their masses suggesting that they have lost considerable mass.

scholarly journals A planet within the debris disk around the pre-main-sequence star AU Microscopii

Nature ◽  
2020 ◽  
Vol 582 (7813) ◽  
pp. 497-500 ◽  
Author(s):  
Peter Plavchan ◽  
Thomas Barclay ◽  
Jonathan Gagné ◽  
Peter Gao ◽  
Bryson Cale ◽  
...  
Keyword(s):  
Main Sequence ◽  
Main Sequence Star ◽  
Debris Disk

scholarly journals Disks and Toroids Around Young Stars

1987 ◽  
Vol 115 ◽  
pp. 239-253 ◽  
Author(s):  
L.F. Rodríguez
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Observational Evidence ◽  
Young Stars ◽  
The Other ◽  
Main Sequence Star ◽  
Circumstellar Disk ◽  
The Sun ◽  
Bipolar Outflows ◽  
The One

We review the observational evidence for interstellar and circumstellar size gaseous structures that appear to be collimating the bipolar outflows observed in regions of star formation. In particular, there is growing evidence for circumstellar disk-like objects that may be related to a protoplanetary cloud like the one that once surrounded the Sun. There are similarities between these disks around young stars and that found around the main sequence star β Pictoris. Both flattened structures around L1551 IRS5 and β Pictoris appear to have an inner “hole” with radius of a few tens of AU. On the other hand, there is observational support for focusing and collimation processes acting on the same source from tens of AU (circumstellar dimensions) to tenths of pc (interstellar dimensions).

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