Rotational Behavior of the Main-Sequence Stars and its Plausible Consequences Concerning Formation of Planetary Systems.

1965 ◽  
Vol 141 ◽  
pp. 985 ◽  
Author(s):  
Su-Shu Huang
Keyword(s):  
Main Sequence ◽  
Planetary Systems ◽  
Rotational Behavior ◽  
Main Sequence Stars

scholarly journals Characterizing planetesimal belts through the study of debris dust

2010 ◽  
Vol 6 (S276) ◽  
pp. 54-59
Author(s):  
Amaya Moro-Martín
Keyword(s):  
Solar System ◽  
Main Sequence ◽  
Planetary Systems ◽  
Dust Particles ◽  
Debris Disks ◽  
Main Sequence Stars ◽  
Wide Range ◽  
Robust Process

AbstractMain sequence stars are commonly surrounded by disks of dust. From lifetime arguments, it is inferred that the dust particles are not primordial but originate from the collision of planetesimals, similar to the asteroids, comets and KBOs in our Solar system. The presence of these debris disks around stars with a wide range of masses, luminosities, and metallicities, with and without binary companions, is evidence that planetesimal formation is a robust process that can take place under a wide range of conditions. Debris disks can help us learn about the formation, evolution and diversity of planetary systems.

scholarly journals Planetary Systems

1999 ◽  
Vol 172 ◽  
pp. 313-316
Author(s):  
Pawel Artymowicz
Keyword(s):  
Radial Velocity ◽  
Main Sequence ◽  
Direct Evidence ◽  
Planetary System ◽  
Planetary Systems ◽  
Main Sequence Stars ◽  
The Past ◽  
Exoplanetary Systems ◽  
Beta Pictoris

AbstractThe past decade brought direct evidence of the previously surmised exoplanetary systems. A variety of planetary system types exist those around pulsars, around both young and old main-sequence stars (as evidenced by planetesimal disks of the Beta Pictoris-type), and the mature giant exoplanets found in radial velocity surveys. The surprising diversity of the exoplanetary systems is addressed by several theories of their origin.

scholarly journals The Population of Debris Discs Orbiting Subgiants

2013 ◽  
Vol 8 (S299) ◽  
pp. 328-329
Author(s):  
Amy Bonsor ◽  
Grant M. Kennedy ◽  
Justin R. Crepp ◽  
John A. Johnson ◽  
Mark C. Wyatt ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Main Sequence ◽  
Planetary Systems ◽  
Main Sequence Stars ◽  
Intermediate Mass ◽  
Intermediate Mass Stars

AbstractWhilst debris discs orbiting main-sequence stars are well studied, very little is known regarding their fate when the star evolves onto the giant branch. For intermediate mass (A-type) stars, giants provide a unique opportunity to detect planets using the radial velocity technique, otherwise prohibited by high jitter levels and rotationally broadened lines in main-sequence intermediate mass (A-type) stars. Such stars can provide key insights into the structure of planetary systems around intermediate mass stars. In our Herschel OT1 program (PI Bonsor) we searched for the presence of debris discs orbiting a sample of 36 subgiants, half of which have RV detected companions. Our best detection is the resolved debris disc orbiting κ CrB.

scholarly journals Origins of Hot Jupiters

2018 ◽  
Vol 56 (1) ◽  
pp. 175-221 ◽  
Author(s):  
Rebekah I. Dawson ◽  
John Asher Johnson
Keyword(s):  
Solar System ◽  
Main Sequence ◽  
Planetary Systems ◽  
Main Sequence Stars ◽  
High Eccentricity ◽  
Hot Jupiters ◽  
In Situ Formation ◽  
Tidal Migration ◽  
Hot Jupiter

Hot Jupiters were the first exoplanets to be discovered around main sequence stars and astonished us with their close-in orbits. They are a prime example of how exoplanets have challenged our textbook, solar-system inspired story of how planetary systems form and evolve. More than twenty years after the discovery of the first hot Jupiter, there is no consensus on their predominant origin channel. Three classes of hot Jupiter creation hypotheses have been proposed: in situ formation, disk migration, and high-eccentricity tidal migration. Although no origin channel alone satisfactorily explains all the evidence, two major origin channels together plausibly account for properties of hot Jupiters themselves and their connections to other exoplanet populations.

scholarly journals How accurately can we age-date solar-type dwarfs using activity/rotation diagnostics?

2008 ◽  
Vol 4 (S258) ◽  
pp. 375-382 ◽  
Author(s):  
Eric E. Mamajek
Keyword(s):  
Main Sequence ◽  
Structural Evolution ◽  
Planetary Systems ◽  
Age Dating ◽  
Rossby Number ◽  
Main Sequence Stars ◽  
Primary Motivation ◽  
X Ray ◽  
Recent Interest ◽  
Solar Type

AbstractIt is well established that activity and rotation diminishes during the life of sun-like main sequence (~F7-K2V) stars. Indeed, the evolution of rotation and activity among these stars appears to be so deterministic that their rotation/activity diagnostics are often utilized as estimators of stellar age. A primary motivation for the recent interest in improving the ages of solar-type field dwarfs is in understanding the evolution of debris disks and planetary systems. Reliable isochronal age-dating for field, solar-type main sequence stars is very difficult given the observational uncertainties and multi-Gyr timescales for significant structural evolution. Observationally, significant databases of activity/rotation diagnostics exist for field solar-type field dwarfs (mainly from chromospheric and X-ray activity surveys).But how well can we empirically age-date solar-type field stars using activity/rotation diagnostics?Here I summarize some recent results for F7-K2 dwarfs from an analysis by Mamajek & Hillenbrand (2008), including an improved “gyrochronology” [Period(color, age)] calibration, improved chromospheric (R′HK) and X-ray (log(LX/Lbol)) activity vs. rotation (via Rossby number) relations, and a chromospheric vs. X-ray activity relation that spans four orders of magnitude in log(LX/Lbol). Combining these relations, one can produce predicted chromospheric and X-ray activity isochrones as a function of color and age for solar type dwarfs.

Chromospheric activity as a function of age in main-sequence stars

1966 ◽  
Vol 24 ◽  
pp. 40-43
Author(s):  
O. C. Wilson ◽  
A. Skumanich
Keyword(s):  
Main Sequence ◽  
The Sun ◽  
Main Sequence Stars ◽  
Tentative Conclusion ◽  
Chromospheric Activity ◽  
General Field ◽  
Large Clusters

Evidence previously presented by one of the authors (1) suggests strongly that chromospheric activity decreases with age in main sequence stars. This tentative conclusion rests principally upon a comparison of the members of large clusters (Hyades, Praesepe, Pleiades) with non-cluster objects in the general field, including the Sun. It is at least conceivable, however, that cluster and non-cluster stars might differ in some fundamental fashion which could influence the degree of chromospheric activity, and that the observed differences in chromospheric activity would then be attributable to the circumstances of stellar origin rather than to age.

On The Radii of Ap Stars

1976 ◽  
Vol 32 ◽  
pp. 49-55 ◽  
Author(s):  
F.A. Catalano ◽  
G. Strazzulla
Keyword(s):  
Observational Data ◽  
Line Width ◽  
Main Sequence ◽  
Main Sequence Stars ◽  
Ap Stars

SummaryFrom the analysis of the observational data of about 100 Ap stars, the radii have been computed under the assumption that Ap are main sequence stars. Radii range from 1.4 to 4.9 solar units. These values are all compatible with the Deutsch's period versus line-width relation.

Pre–Main-Sequence Stars in the Young Galactic Cluster IC 4996: A CCD Photometric Study

1998 ◽  
Vol 116 (4) ◽  
pp. 1801-1809 ◽  
Author(s):  
Antonio J. Delgado ◽  
Emilio J. Alfaro ◽  
André Moitinho ◽  
José Franco
Keyword(s):  
Main Sequence ◽  
Photometric Study ◽  
Main Sequence Stars ◽  
Galactic Cluster
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