Influence of Planets on the Magnetic Activity of Sun-Like Stars

2018 ◽  
Vol 13 (S340) ◽  
pp. 242-243
Author(s):  
Shashanka R. Gurumath ◽  
K. M. Hiremath ◽  
V. Ramasubramanian
Keyword(s):  
Physical Properties ◽  
Power Law ◽  
Magnetic Activity ◽  
The Sun ◽  
Stellar Activity ◽  
Index Data ◽  
Planetary Mass ◽  
Power Law Decay ◽  
Host Stars

AbstractBy considering the physical properties of Sun-like G stars and their exoplanets, present study examines whether presence of planets near the host stars enhances their stellar activity. In order to attain this goal, chromospheric RHK index data-a proxy for the magnetic activity-for the stars with and without planets is considered. With the reasonable constraints on the exoplanetary data, we obtained a power law decay relationship between the magnetic activity of host stars and their ages, for stars with and without planets. Both these results strongly suggest that there is no difference in magnetic activity of the sun-like stars with and without presence of planets. In order to confirm this result, further we also examine an association between the host stars RHK index that have exoplanets and their respective exoplanetary masses. We find that magnitude of RHK (hence magnetic activity) of the host stars is independent of presence of planetary mass in its vicinity.

scholarly journals The future of helioseismology

2009 ◽  
Vol 5 (H15) ◽  
pp. 352-353
Author(s):  
Alexander G. Kosovichev
Keyword(s):  
Solar Cycle ◽  
Physical Properties ◽  
Active Regions ◽  
Magnetic Activity ◽  
Solar Dynamo ◽  
Current Status ◽  
The Sun ◽  
Interior Structure ◽  
Structure And Dynamics ◽  
Solar Magnetic Activity

AbstractHelioseismology has provided us with the unique knowledge of the interior structure and dynamics of the Sun, and the variations with the solar cycle. However, the basic mechanisms of solar magnetic activity, formation of sunspots and active regions are still unknown. Determining the physical properties of the solar dynamo, detecting emerging active regions and observing the subsurface dynamics of sunspots are among the most important and challenging problems. The current status and perspectives of helioseismology are briefly discussed.

Statistical properties of starspots on solar-type stars and their correlation with flare activity

2018 ◽  
Vol 14 (A30) ◽  
pp. 369-372
Author(s):  
Hiroyuki Maehara
Keyword(s):  
Power Law ◽  
Solar Flares ◽  
Magnetic Activity ◽  
Statistical Properties ◽  
Flare Activity ◽  
The Sun ◽  
Power Law Distribution ◽  
Physical Processes ◽  
Energy Distributions ◽  
Solar Type

AbstractWe analyzed the statistical properties of starspots on solar-type stars and the correlation between properties of starspots and flare activity using observations from the Kepler mission. We found the size distribution of starspots on solar-type stars shows the power-law distribution and both size distributions of starspots on slowly-rotating solar-type stars and of relatively large sunspots are roughly lie on the same power-law line. We also found that the frequency-energy distributions for superflares and solar flares from spots with different sizes are the same for solar-type stars and the Sun. These results suggest that the magnetic activity on solar-type stars and that on the Sun are caused by the same physical processes

scholarly journals Improved rotation-activity-age relations in Sun-like stars

2016 ◽  
Vol 12 (S328) ◽  
pp. 274-281
Author(s):  
Jorge Meléndez ◽  
Leonardo A. dos Santos ◽  
Fabrício C. Freitas
Keyword(s):  
Mass Transfer ◽  
Rotational Velocity ◽  
Magnetic Activity ◽  
Spectroscopic Binaries ◽  
The Sun ◽  
Stellar Activity ◽  
Large Sample ◽  
Chemical Signatures ◽  
Age Relations

AbstractThe evolution of rotational velocity and magnetic activity with age follows approximately at−1/2relation, the famous Skumanich law. Using a large sample of about 80 solar twins with precise ages, we show departures from this law. We found a steep drop in rotational velocity and activity in the first 2-3 Gyr and afterwards there seems to be a shallow decrease. Our inferred rotational periods suggest that the Sun will continue to slow down, validating thus the use of gyrochronology beyond solar age. The Sun displays normal rotational velocity and activity when compared to solar twins of solar age. We also show that stars with exceedingly high stellar activity for their age are spectroscopic binaries that also exhibit enhanced rotational velocities and chemical signatures of mass transfer.

scholarly journals Photometric magnetic-activity metrics tested with the Sun: application toKeplerM dwarfs

2014 ◽  
Vol 4 ◽  
pp. A15 ◽  
Author(s):  
Savita Mathur ◽  
David Salabert ◽  
Rafael A. García ◽  
Tugdual Ceillier
Keyword(s):  
Magnetic Activity ◽  
The Sun

scholarly journals Search for stellar companions of exoplanet host stars by exploring the second ESA-Gaia data release

2019 ◽  
Vol 490 (4) ◽  
pp. 5088-5102 ◽  
Author(s):  
M Mugrauer
Keyword(s):  
Main Sequence ◽  
Stellar Systems ◽  
Sequence Evolution ◽  
The Sun ◽  
M Dwarfs ◽  
Primary Star ◽  
True Nature ◽  
Quadruple System ◽  
Data Release ◽  
Host Stars

ABSTRACT A new survey is presented, which explores the second data release of the ESA-Gaia mission, in order to search for stellar companions of exoplanet host stars, located at distances closer than about 500 pc around the Sun. In total, 176 binaries, 27 hierarchical triples, and one hierarchical quadruple system are detected among more than 1300 exoplanet host stars, whose multiplicity is investigated, yielding a multiplicity rate of the exoplanet host stars of at least about 15  per cent. The detected companions and the exoplanet host stars are equidistant and share a common proper motion, as it is expected for gravitationally bound stellar systems, proven with their accurate Gaia astrometry. The companions exhibit masses in the range between about 0.078 and 1.4 M⊙ with a peak in their mass distribution between 0.15 and $0.3\, \mathrm{M}_{\odot }$. The companions are separated from the exoplanet host stars by about 20 up to 9100 au, but are found most frequently within a projected separation of 1000 au. While most of the detected companions are early M dwarfs, eight white dwarf companions of exoplanet host stars are also identified in this survey, whose true nature is revealed with their photometric properties. Hence, these degenerated companions and the exoplanet host stars form evolved stellar systems with exoplanets, which have survived (physically but also dynamically) the post-main-sequence evolution of their former primary star.

scholarly journals When an oscillating center in an open system undergoes power law decay

2018 ◽  
Vol 57 (3) ◽  
pp. 750-768 ◽  
Author(s):  
Sandip Saha ◽  
Gautam Gangopadhyay
Keyword(s):  
Power Law ◽  
Open System ◽  
Power Law Decay

scholarly journals Unbound Close Stellar Encounters in the Solar Neighborhood

2022 ◽  
Vol 163 (2) ◽  
pp. 44
Author(s):  
Bradley M. S. Hansen
Keyword(s):  
Spectral Type ◽  
Main Sequence ◽  
Radial Distance ◽  
Solar Neighborhood ◽  
Limiting Factors ◽  
Line Of Sight ◽  
The Sun ◽  
Finite Set ◽  
Host Stars ◽  
Migration Event

Abstract We present a catalog of unbound stellar pairs, within 100 pc of the Sun, that are undergoing close, hyperbolic, encounters. The data are drawn from the GAIA EDR3 catalog, and the limiting factors are errors in the radial distance and unknown velocities along the line of sight. Such stellar pairs have been suggested to be possible events associated with the migration of technological civilizations between stars. As such, this sample may represent a finite set of targets for a SETI search based on this hypothesis. Our catalog contains a total of 132 close passage events, featuring stars from across the entire main sequence, with 16 pairs featuring at least one main-sequence star of spectral type between K1 and F3. Many of these stars are also in binaries, so that we isolate eight single stars as the most likely candidates to search for an ongoing migration event—HD 87978, HD 92577, HD 50669, HD 44006, HD 80790, LSPM J2126+5338, LSPM J0646+1829 and HD 192486. Among host stars of known planets, the stars GJ 433 and HR 858 are the best candidates.

scholarly journals ‘Sumer’ – Solar Ultraviolet Measurements of Emitted Radiation

1994 ◽  
Vol 144 ◽  
pp. 619-624 ◽  
Author(s):  
K. Wilhelm ◽  
W. Curdt ◽  
A. H. Gabriel ◽  
M. Grewing ◽  
M. C. E. Huber ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Extreme Ultraviolet ◽  
Flow Characteristics ◽  
Magnetic Activity ◽  
High Accuracy ◽  
The Sun ◽  
Lower Corona ◽  
Doppler Shifts ◽  
Solar Magnetic Activity ◽  
Solar Ultraviolet

AbstractThe experiment Solar Ultraviolet Measurements of Emitted Radiation (SUMER) is designed for the investigations of plasma flow characteristics, turbulence and wave motions, plasma densities and temperatures, structures and events associated with solar magnetic activity in the chromosphere, the transition zone and the corona. Specifically, SUMER will measure profiles and intensities of extreme ultraviolet (EUV) lines emitted in the solar atmosphere ranging from the upper chromosphere to the lower corona; determine line broadenings, spectral positions and Doppler shifts with high accuracy; provide stigmatic images of selected areas of the Sun in the EUV with high spatial, temporal and spectral resolution and obtain full images of the Sun and the inner corona in selectable EUV lines, corresponding to a temperature range from 104to more than 1.8 x 106K. The spatial and spectral resolution capabilities of the instrument will be considered in this contribution in some detail, and a new detector concept will be introduced.

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