scholarly journals Resolved ALMA Continuum Image of the Circumbinary Ring and Circumstellar Disks in the L1551 IRS 5 System

2019 ◽  
Vol 882 (1) ◽  
pp. L4 ◽  
Author(s):  
Fernando Cruz-Sáenz de Miera ◽  
Ágnes Kóspál ◽  
Péter Ábrahám ◽  
Hauyu Baobab Liu ◽  
Michihiro Takami
Keyword(s):  
Circumstellar Disks ◽  
Continuum Image

The Infancy of Solar-Type Stars and its Relevance for the Origin of Life

1997 ◽  
Vol 161 ◽  
pp. 267-282 ◽  
Author(s):  
Thierry Montmerle
Keyword(s):  
Main Sequence ◽  
Solar Nebula ◽  
Circumstellar Disks ◽  
T Tauri Stars ◽  
Necessary Condition ◽  
Sequence Evolution ◽  
T Tauri ◽  
Solar Type ◽  
Optical Domain ◽  
The Origin Of Life

AbstractFor life to develop, planets are a necessary condition. Likewise, for planets to form, stars must be surrounded by circumstellar disks, at least some time during their pre-main sequence evolution. Much progress has been made recently in the study of young solar-like stars. In the optical domain, these stars are known as «T Tauri stars». A significant number show IR excess, and other phenomena indirectly suggesting the presence of circumstellar disks. The current wisdom is that there is an evolutionary sequence from protostars to T Tauri stars. This sequence is characterized by the initial presence of disks, with lifetimes ~ 1-10 Myr after the intial collapse of a dense envelope having given birth to a star. While they are present, about 30% of the disks have masses larger than the minimum solar nebula. Their disappearance may correspond to the growth of dust grains, followed by planetesimal and planet formation, but this is not yet demonstrated.

scholarly journals STRUCTURE AND EVOLUTION OF PRE-MAIN-SEQUENCE CIRCUMSTELLAR DISKS

2009 ◽  
Vol 701 (1) ◽  
pp. 260-282 ◽  
Author(s):  
Andrea Isella ◽  
John M. Carpenter ◽  
Anneila I. Sargent
Keyword(s):  
Main Sequence ◽  
Circumstellar Disks

scholarly journals IPHAS A-type Stars with Mid-IR Excesses in Spitzer Surveys

2009 ◽  
Vol 5 (H15) ◽  
pp. 815-815
Author(s):  
Antonio S. Hales ◽  
Michael J. Barlow ◽  
Janet E. Drew ◽  
Yvonne C. Unruh ◽  
Robert Greimel ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Main Sequence ◽  
Terrestrial Planet ◽  
Circumstellar Disks ◽  
Main Sequence Stars ◽  
Intermediate Mass ◽  
Mid Infrared ◽  
Isaac Newton ◽  
Intermediate Mass Stars ◽  
Dust Disks

AbstractThe Isaac Newton Photometric H-Alpha Survey (IPHAS) provides (r′-Hα)-(r′-i′) colors, which can be used to select AV0-5 Main Sequence star candidates (age~20-200 Myr). By combining a sample of 23050 IPHAS-selected A-type stars with 2MASS, GLIMPSE and MIPSGAL photometry we searched for mid-infrared excesses attributable to dusty circumstellar disks. Positional cross-correlation yielded a sample of 2692 A-type stars, of which 0.6% were found to have 8-μm excesses above the expected photospheric values. The low fraction of main sequence stars with mid-IR excesses found in this work indicates that dust disks in the terrestrial planet zone of Main Sequence intermediate mass stars are rare. Dissipation mechanisms such as photo-evaporation, grain growth, collisional grinding or planet formation could possibly explain the depletion of dust detected in the inner regions of these disks.

scholarly journals Tracing planet-induced structures in circumstellar disks using molecular lines

2015 ◽  
Vol 579 ◽  
pp. A105 ◽  
Author(s):  
F. Ober ◽  
S. Wolf ◽  
A. L. Uribe ◽  
H. H. Klahr
Keyword(s):  
Circumstellar Disks ◽  
Molecular Lines

Extreme Adaptive Optics

2018 ◽  
Vol 56 (1) ◽  
pp. 315-355 ◽  
Author(s):  
Olivier Guyon
Keyword(s):  
Adaptive Optics ◽  
Thermal Emission ◽  
Contrast Ratio ◽  
Angular Separation ◽  
Circumstellar Disks ◽  
Spectroscopic Characterization ◽  
Central Star ◽  
High Contrast ◽  
Direct Imaging ◽  
Segmented Mirror

Over the last two decades, several thousand exoplanets have been identified, and their study has become a high scientific priority. Direct imaging of nearby exoplanets and the circumstellar disks in which they form and evolve is challenging due to the high contrast ratio and small angular separation relative to the central star. Exoplanets are typically within 1 arcsec of, and between 4 and 10 orders of magnitude fainter than, the stars they orbit. To meet these challenges, ground-based telescopes must be equipped with extreme adaptive optics (ExAO) systems optimized to acquire high-contrast images of the immediate surrounding of nearby bright stars. Current ExAO systems have the sensitivity to image thermal emission from young massive planets in near-IR, while future systems deployed on Giant Segmented Mirror Telescopes will image starlight reflected by lower-mass rocky planets. Thanks to rapid progress in optical coronagraphy, wavefront control, and data analysis techniques, direct imaging and spectroscopic characterization of habitable exoplanets will be within reach of the next generation of large ground-based telescopes.

Crystallization of Silicate Particles in Circumstellar Disks by Shock Waves

2009 ◽  
Author(s):  
T. Nakamoto ◽  
H. Miura ◽  
Tomonori Usuda ◽  
Motohide Tamura ◽  
Miki Ishii
Keyword(s):  
Shock Waves ◽  
Circumstellar Disks

scholarly journals Radiative transfer in circumstellar disks

2009 ◽  
Vol 498 (3) ◽  
pp. 793-800 ◽  
Author(s):  
S. D. Hügelmeyer ◽  
S. Dreizler ◽  
P. H. Hauschildt ◽  
A. Seifahrt ◽  
D. Homeier ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Circumstellar Disks

scholarly journals Line emission from circumstellar disks around A stars

2003 ◽  
Vol 397 (3) ◽  
pp. 1129-1141 ◽  
Author(s):  
I. Kamp ◽  
G.-J. van Zadelhoff ◽  
E. F. van Dishoeck ◽  
R. Stark
Keyword(s):  
Line Emission ◽  
Circumstellar Disks

scholarly journals MODELING CIRCUMSTELLAR DISKS OF B-TYPE STARS WITH OBSERVATIONS FROM THE PALOMAR TESTBED INTERFEROMETER

2013 ◽  
Vol 145 (5) ◽  
pp. 141 ◽  
Author(s):  
B. J. Grzenia ◽  
C. Tycner ◽  
C. E. Jones ◽  
S. A. Rinehart ◽  
G. T. van Belle ◽  
...  
Keyword(s):  
Circumstellar Disks
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