A0535+26

This page is still edited

System Overview

Porb	111.1	days	Finger et al. 2006
Pspin	103.4	s	Rosenberg et al. 1975, Makino et al. 1989, ...
B	4x1012	G	Kendziorra et al. 1994
a sin i	267	lt-sec	Finger et al. 2006
eccentricity	0.47		Finger et al. 2006
ω	130	degree	Finger et al. 2006
Τperiastron	53613.0	MJD	Finger et al. 2006
distance	2	kpc	Steele et al. 1994

Optical companion

HDE 245770, spectral class: O9.7IIIe (Giangrande et al. 1980), B0 IIIe (Steele et al. 1998)

M	14 / 20 / 26	M⊙	de Loore et al. 1984 / Coe et al. 2006 / Haigh et al. 2004
R	14	R⊙	de Loore et al. 1984
Mdot	10-8	M⊙	de Loore et al. 1984
Teff	26000-28000	K	Giovannelli & Graziati 1992
L	0.7 x 105	L⊙	Giovannelli & Graziati 1992

Description

Pulse period and pulse profiles

• pulse shape and intensity are highly variable (Frontera et al. 1985)
• lower energies several, irregularly spaced maxima observed (bradt et al. 1976)
• double-peaked pulse profiles above 20 keV
• asymmetric main and more symmetric secondary peak (Kendziorra et al. 1994)
• pulsed fraction increases with energy (Frontera et al. 1985, Kendziorra et al. 1994)

Spectrum

• hard power law with index 0.8-1.1 with exponential cutoff (Ricketts et al. 1975, Kendziorra et al. 1994)
• 2 cyclotron lines at about 50, 100 keV
• Pulse phase analysis: main pulse spectrum harder than secondary pulse (Kendziorra et al. 1994)