Query : 2003A&A...402..201S

2003A&A...402..201S - Astronomy and Astrophysics, volume 402, 201-209 (2003/4-4)

Cyclotron spectroscopy of HU Aquarii.


Abstract (from CDS):

We present the results of a combined analysis of low-resolution spectroscopy and high-speed optical photometry of the bright eclipsing polar HU Aqr, obtained in its high accretion state. Cyclotron harmonic emission in a field of B≃34MG became evident and could be traced through the whole optical bright phase. The cyclotron harmonics display an asymmetric motion as a function of phase which requires a certain forward tilt of the magnetic field lines in the emission region. The optical bright phase is more extended than the bright phase in soft X-rays suggesting a more extended emission region. Also, ingress into and egress from the optical eclipse last much longer in the optical than at X-ray wavelengths. These observations require the existence of an accretion arc with total extent of about 20°. The soft X-ray accretion spot is located at the far end of the arc, where the bulk of matter is accreted. The arc is likely to be more extended than the foot-line of field lines connecting to the ballistic accretion stream in a dipolar geometry. This together with the required tilt of the accreting field lines suggest a more complex magnetic geometry than a simple dipole.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - stars: binaries: eclipsing - magnetic fields - stars: individual: HU Aqr

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 V* VV Pup CV* 08 15 06.8009599464 -19 03 17.765706024     13.90     M7V 396 0
2 V* V834 Cen CV* 14 09 07.2863511816 -45 17 16.023776676   16.0   15.301   M6.5 315 0
3 PG 1550+191 CV* 15 52 47.1968971224 +18 56 28.844471472   16.4 15.46 17.0   M6.5Ve 188 0
4 V* HU Aqr CV* 21 07 58.1944529400 -05 17 40.557671916   16.198 15.814 14.891   D+M4V 273 1

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