Polars (AM Her stars)

© 1998 M. A. Garlick: "AM Herculis"

© 1998 M.A. Garlick: "Magnetic Accretion"

In polars, the white dwarf magnetic field is so strong that:
	1) The white dwarf is spin-synchronized with the binary (Pspin = Porb), and
	2) No disk forms - accretion takes places directly into the white dwarf magnetosphere.
Like intermediate polars, polars are strong hard X-ray sources, but the X-ray, extreme ultraviolet, ultraviolet, and optical radiation is pulsed at the binary orbital period.
The photoionizing flux in polars and intermediate polars is brutal: all the exposed plasma in the binary - the inner face of the secondary, the accretion stream, the magnetosphere, the surface of white dwarf - are irradiated with a hard photoionizing flux of luminosity ~ 1033 erg/s or ~ 2 x 1010 megatons/s.
The irradiated surface of the white dwarf in particular is heated to a temperature ~ 105 K (10 eV), and so is a strong source of extreme ultraviolet and soft X-ray radiation.

Extreme Ultraviolet Explorer Phase-Resolved Spectroscopy of V834 Centauri
Mauche, C. W.
2002, Ap. J., 578, 439.
[UCRL-JC-146242]


EUVE Spectroscopy of Polars
Mauche, C. W.
1999, in Annapolis Workshop on Magnetic Cataclysmic Variables, ed. C. Hellier and K. Mukai (San Francisco: ASP), p. 157.
[UCRL-JC-132113]


ORFEUS II Far-UV Spectroscopy of AM Herculis
Mauche, C. W., and Raymond, J. C.
1998, Ap. J., 505, 869.
[UCRL-JC-129084]


Extreme Ultraviolet Spectroscopy of the White Dwarf Photosphere in AM Herculis
Paerels, F., Hur, M. Y., Mauche, C. W., and Heise, J.
1996, Ap. J., 464, 884.


Extreme Ultraviolet Spectroscopy of Magnetic Cataclysmic Variables
Paerels, F., Hur, M. Y., and Mauche, C. W.
1996, in Astrophysics in the Extreme Ultraviolet, ed. S. Bowyer and R. F. Malina (Dordrecht: Kluwer), p. 309.

ORFEUS Observations of AM Herculis
Raymond, J. C., Mauche, C. W., Hurwitz, M., and Bowyer, S.
1995, Ap. J., 440, 331.


ORFEUS and EUVE Observations of AM Herculis
Mauche, C. W., Paerels, F. B. S., and Raymond, J. C.
1995, in Cape Workshop on Magnetic Cataclysmic Variables, ed. D. A. H. Buckley and B. Warner (San Francisco: ASP), p. 298.
[UCRL-JC-120557]

EUVE Observations of UZ Fornacis and AM Herculis
Warren, J. K., Vallerga, J. V., Mauche, C. W., Mukai, K., and Siegmund, O. H. W.
1994, in Interacting Binary Stars, ed. A. W. Shafter (San Francisco: ASP), p. 353.

Extreme Ultraviolet Explorer Observations of the Magnetic Cataclysmic Variable RE 1938-461
Warren, J. K., Vallerga, J. V., Mauche, C. W., Mukai, K., and Siegmund, O. H. W.
1993, Ap. J. (Letters), 414, L69.

Novae	CV Subtypes	Non-Magnetic CVs	Intermediate Polars	Polars
Last modified October 5, 2004
UCRL-MI-135159