An evolutionary study of magnetic Ap stars in 4 northern open clusters

2005 ◽  
Vol 17 ◽  
pp. 349-352
Author(s):  
J. Silvester ◽  
G.A. Wade ◽  
D.A. Hanes
Keyword(s):  
Open Clusters ◽  
Evolutionary Study ◽  
Ap Stars

Are All Blue Stragglers Ap Stars?

1976 ◽  
Vol 32 ◽  
pp. 357-364
Author(s):  
E.S. Pendl ◽  
W. Seggewiss
Keyword(s):  
Spectroscopic Data ◽  
Open Cluster ◽  
Open Clusters ◽  
Blue Stragglers ◽  
The Status ◽  
Ap Stars

SummaryA list of open clusters with blue stragglers studied for Ap characteristics is presented. In addition to previously published results new spectroscopic data are given of blue stragglers in the open cluster IC 4756 derived from ESO spectrograms taken in 1973. Preliminary conclusions concerning the status of Ap stars and blue stragglers are drawn.

A search for AP stars in open clusters.

1973 ◽  
Vol 181 ◽  
pp. 805 ◽  
Author(s):  
A. Young ◽  
A. E. Martin
Keyword(s):  
Open Clusters ◽  
Ap Stars

scholarly journals Stellar Rotation in Open Clusters (Review Paper)

1970 ◽  
Vol 4 ◽  
pp. 193-203
Author(s):  
Helmut A. Abt
Keyword(s):  
Review Paper ◽  
Orbital Motion ◽  
Open Clusters ◽  
Stellar Rotation ◽  
Open Clusters And Associations ◽  
Magnetic Braking ◽  
Ap Stars

AbstractThe characteristics of rotational velocities in fifteen open clusters and associations are summarized. The differences in mean rotational velocities observed between individual groups are found to be due primarily to three mechanisms: evolutionary expansion, tidal coupling of rotational and orbital motion in binaries, and magnetic braking in Ap stars.

scholarly journals Statistics of CP Stars in a Magnitude-Limited Sample: The Bright Star Catalogue

1993 ◽  
Vol 138 ◽  
pp. 629-633 ◽  
Author(s):  
H. Schneider
Keyword(s):  
Incomplete Data ◽  
Main Sequence ◽  
Open Clusters ◽  
Bright Star ◽  
Limited Sample ◽  
The Past ◽  
Star Catalogue ◽  
General Catalogue ◽  
The Moment ◽  
Ap Stars

AbstractIn the past several authors investigated the incidence of CP Stars among field stars of the upper main sequence, e.g. Jaschek&Jascheck (1967), Wolff (1968), Abt (1979), or in open clusters e.g. Young&Martin (1973), Hartoog (1976), North&Cramer (1981). But the published values seem not to be very precise or universal because of the use of incomplete data bases like Osawa’s list (1965) or the old version of the Bright Star Catalogue or the concentration on selected samples e.g. open clusters. Only Smith (1973) gave realistic values in the case of CP1 stars.In the meantime two decades passed and many new observations were obtained. In 1982 a new version of the Bright Star Catalogue with better spectral classifications was issued and a supplement to the BS catalogue was published (1983). Furthermore, Renson and co-workers presented 1991 their General Catalogue of Am and Ap Stars (in the following abbreviated to GCAAS). Now the moment has come to establish new and hopefully more precise values of the incidence of CP Stars using the new version of the Bright Star Catalogue and its supplement as the data base.

Observations of neutral hydrogen in open clusters

1967 ◽  
Vol 31 ◽  
pp. 41-43
Author(s):  
Th. Schmidt-Kaler ◽  
R. Schwartz
Keyword(s):  
Neutral Hydrogen ◽  
Open Clusters

Neutral hydrogen is found in every young cluster observed, usually extending beyond the optical diameter, and in some cases showing expanding motions.

The Photometric Properties of the Ap Stars

1976 ◽  
Vol 32 ◽  
pp. 365-377 ◽  
Author(s):  
B. Hauck
Keyword(s):  
Physical Properties ◽  
Ap Stars

The Ap stars are numerous - the photometric systems tool It would be very tedious to review in detail all that which is in the literature concerning the photometry of the Ap stars. In my opinion it is necessary to examine the problem of the photometric properties of the Ap stars by considering first of all the possibility of deriving some physical properties for the Ap stars, or of detecting new ones. My talk today is prepared in this spirit. The classification by means of photoelectric photometric systems is at the present time very well established for many systems, such as UBV, uvbyβ, Vilnius, Geneva and DDO systems. Details and methods of classification can be found in Golay (1974) or in the proceedings of the Albany Colloquium edited by Philip and Hayes (1975).

Variation of Heavy Element Lines in the Ap Stars

1976 ◽  
Vol 32 ◽  
pp. 311-320 ◽  
Author(s):  
I.A. Aslanov ◽  
Yu. S. Rustamov ◽  
M. Kowalski
Keyword(s):  
Heavy Element ◽  
Ap Stars

SummaryLines of U II were found in the spectrograms of the Ap stars HR 465, 17 Com A and HD 224801. Pm II lines were found in HR 465. These lines vary in intensity in HR 465 with a period of 6h41m, in 17 Com A of 71m, and in HD 224801 of 6h.

Peculiarity Parameters

1976 ◽  
Vol 32 ◽  
pp. 233-254
Author(s):  
H. M. Maitzen
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Theoretical Work ◽  
Observational Evidence ◽  
Rotator Model ◽  
Peculiar Behaviour ◽  
Field Spectrum ◽  
Oblique Rotator ◽  
Ap Stars ◽  
The Way

Ap stars are peculiar in many aspects. During this century astronomers have been trying to collect data about these and have found a confusing variety of peculiar behaviour even from star to star that Struve stated in 1942 that at least we know that these phenomena are not supernatural. A real push to start deeper theoretical work on Ap stars was given by an additional observational evidence, namely the discovery of magnetic fields on these stars by Babcock (1947). This originated the concept that magnetic fields are the cause for spectroscopic and photometric peculiarities. Great leaps for the astronomical mankind were the Oblique Rotator model by Stibbs (1950) and Deutsch (1954), which by the way provided mathematical tools for the later handling pulsar geometries, anti the discovery of phase coincidence of the extrema of magnetic field, spectrum and photometric variations (e.g. Jarzebowski, 1960).

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