scholarly journals Diamagnetic Abundance Differentiation in the Solar System

1992 ◽  
Vol 150 ◽  
pp. 425-426
Author(s):  
Raphael Steinitz ◽  
Estelle Kunoff
Keyword(s):  
Solar Wind ◽  
Solar System ◽  
Solar Corona ◽  
Ionization Potential ◽  
Chemical Abundances ◽  
Magnetic Structures ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
Chemically Peculiar Stars ◽  
First Ionization Potential

Chemical abundances in the solar corona or solar wind compared to those in the photosphere differentiate according to first ionization potential (FIP). We suggest that the effect is the result of diamagnetic diffusion pumps operating in the presence of gravitation and diverging magnetic structures. We then comment briefly on implications concerning abundances in the solar system and chemically peculiar stars.

scholarly journals Element Abundances and FIP: SEPs, Corona, and Solar Wind

2021 ◽  
pp. 167-185
Author(s):  
Donald V. Reames
Keyword(s):  
Solar Wind ◽  
Solar Corona ◽  
Ionization Potential ◽  
Open Field ◽  
Energetic Particles ◽  
Physical Processes ◽  
Element Abundances ◽  
First Ionization Potential

AbstractWe have used abundance measurements to identify the sources and the physical processes of acceleration and transport of SEPs. Here we study energetic particles themselves as samples of the solar corona that is their origin, distinguishing the corona from the photosphere and the SEPs from the solar wind. Theoretically, differences in the first ionization potential “FIP effect” may distinguish closed- and open-field regions at the base of the corona, which may also distinguish SEPs from the solar wind. There is not a single coronal FIP effect, but two patterns, maybe three. Are there variations? What about He?

Abundance Modification by the Diamagnetic Effect

1994 ◽  
Vol 144 ◽  
pp. 498
Author(s):  
R. Steinitz ◽  
E. Kunoff
Keyword(s):  
Solar Wind ◽  
Ionization Potential ◽  
Transition Zone ◽  
Chemical Abundance ◽  
Magnetic Structures ◽  
First Ionization Potential ◽  
Diamagnetic Effect

AbstractIt is well established that there is a chemical abundance differentiation between material in the photosphere, and material in the corona or the solar wind. It appears that this effect is according to first ionization potential (FIP).We explore the possibility that this differentiation is the result of strong diamagnetic effects experienced by ions in the chromposphere-corona transition zone, in the presence of diverging magnetic structures.

Stellar Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 641-650
Author(s):  
J. L. Linsky
Keyword(s):  
Binary Systems ◽  
Stellar Systems ◽  
X Rays ◽  
Magnetic Structures ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
Solar Type ◽  
Chemically Peculiar Stars ◽  
Coronal Structures

AbstractLarge magnetic structures in the coronae of stars containing gas at a wide variety of temperatures are now being studied in X-rays, radio wavelengths, and Hα. Here I will summarize what we are learning about coronal structures in three types of stellar systems: the magnetic chemically peculiar stars, the RS CVn binary systems containing G- and K-type subgiants, and active solar-type dwarfs like V471 Tauri and AB Doradus.

scholarly journals On-line database of photometric observations of magnetic chemically peculiar stars

2007 ◽  
Vol 328 (1) ◽  
pp. 10-15 ◽  
Author(s):  
Z. Mikulášek ◽  
J. Janík ◽  
J. Zverko ◽  
J. Žižňovský ◽  
M. Zejda ◽  
...  
Keyword(s):  
Chemically Peculiar ◽  
Photometric Observations ◽  
Peculiar Stars ◽  
On Line ◽  
Chemically Peculiar Stars

scholarly journals Advanced test of the model stellar atmospheres: the nature of the light variability of magnetic chemically peculiar stars

2008 ◽  
Vol 4 (S252) ◽  
pp. 347-348
Author(s):  
J. Krtička ◽  
Z. Mikulášek ◽  
J. Zverko ◽  
J. Žižňovský ◽  
P. Zvěřina
Keyword(s):  
Chemical Elements ◽  
Horizontal Distribution ◽  
Stellar Atmospheres ◽  
Silicon Iron ◽  
Surface Distribution ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
Distribution Of Elements ◽  
Chemically Peculiar Stars ◽  
Light Variability

AbstractThe magnetic chemically peculiar stars exhibit both inhomogeneous horizontal distribution of chemical elements on their surfaces and the light variability. We show that the observed light variability of these stars can be successfully simulated using models of their stellar atmospheres and adopting the observed surface distribution of elements. The most important elements that influence the light variability are silicon, iron, and helium.

scholarly journals 29. Stellar Spectra

1982 ◽  
Vol 18 (1) ◽  
pp. 343-360 ◽  
Author(s):  
W.K. Bonsack
Keyword(s):  
Stellar Evolution ◽  
Working Group ◽  
Main Sequence ◽  
Symbiotic Stars ◽  
Be Stars ◽  
Stellar Spectra ◽  
Chemically Peculiar ◽  
Peculiar Stars ◽  
Chemically Peculiar Stars ◽  
Ap Stars

During the interval covered by this report, Commission 29 has sponsored or cosponsored the following IAU meetings: Symposium 98 on “Be Stars,” Munich, FRG, April 1981; Colloquium 59, “Effects of Mass-Loss on Stellar Evolution,” Trieste, Italy, September 1980; and Colloquim 70, “The Nature of Symbiotic Stars,” Haute-Provence, France, August 1981. In addition, Commission 29, through its Working Group on Ap Stars, collaborated in the organization of the 23rd Liege International Astrophysical Symposium on Upper Main-Sequence Chemically Peculiar Stars. Several IAU symposia and colloquia proposed for 1982 and 1983 are also cosponsored by Commission 29.

scholarly journals K2 space photometry reveals rotational modulation and stellar pulsations in chemically peculiar A and B stars

2018 ◽  
Vol 616 ◽  
pp. A77 ◽  
Author(s):  
D. M. Bowman ◽  
B. Buysschaert ◽  
C. Neiner ◽  
P. I. Pápics ◽  
M. E. Oksala ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Intrinsic Variability ◽  
B Stars ◽  
Pulsating Stars ◽  
Chemically Peculiar ◽  
Large Scale Magnetic Field ◽  
Peculiar Stars ◽  
Show Evidence ◽  
Chemically Peculiar Stars

Context. The physics of magnetic hot stars and how a large-scale magnetic field affects their interior properties is largely unknown. Few studies have combined high-quality observations and modelling of magnetic pulsating stars, known as magneto-asteroseismology, primarily because of the dearth of detected pulsations in stars with a confirmed and well-characterised large-scale magnetic field. Aims. We aim to characterise observational signatures of rotation and pulsation in chemically peculiar candidate magnetic stars using photometry from the K2 space mission. Thus, we identify the best candidate targets for ground-based, optical spectropolarimetric follow-up observations to confirm the presence of a large-scale magnetic field. Methods. We employed customised reduction and detrending tools to process the K2 photometry into optimised light curves for a variability analysis. We searched for the periodic photometric signatures of rotational modulation caused by surface abundance inhomogeneities in 56 chemically peculiar A and B stars. Furthermore, we searched for intrinsic variability caused by pulsations (coherent or otherwise) in the amplitude spectra of these stars. Results. The rotation periods of 38 chemically peculiar stars are determined, 16 of which are the first determination of the rotation period in the literature. We confirm the discovery of high-overtone roAp pulsation modes in HD 177765 and find an additional 3 Ap and Bp stars that show evidence of high-overtone pressure modes found in roAp stars in the form of possible Nyquist alias frequencies in their amplitude spectra. Furthermore, we find 6 chemically peculiar stars that show evidence of intrinsic variability caused by gravity or pressure pulsation modes. Conclusions. The discovery of pulsations in a non-negligible fraction of chemically peculiar stars make these stars high-priority targets for spectropolarimetric campaigns to confirm the presence of their expected large-scale magnetic field. The ultimate goal is to perform magneto-asteroseismology and probe the interior physics of magnetic pulsating stars.

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