Title: Evidence of Thermonuclear Flame Spreading on Neutron Stars from

Burst Rise Oscillations

Speaker: Manoneeta Chakraborty (Sabanci University)

Date/Time: March 4, 2015 Wednesday at 13:40

Place: Sabancı University, FENS L062

Abstract:
Intense X-ray bursts (type-I bursts), originated from runaway
thermonuclear processes, are observed from the surfaces of many
accreting neutron star Low Mass X-ray Binary (LMXB) systems and they
provide an important tool to constrain the neutron star equation of
state. Periodic intensity variations during these bursts are termed
burst oscillations and such features are observed in about 10% of
thermonuclear bursts. Oscillations during the rising phases of
thermonuclear bursts are hypothesized to originate from an expanding
hot-spot on the surface of the neutron star. We studied the evolution
of oscillations during the rising phase of a large sample of
thermonuclear bursts from 10 bursting neutron stars in order to probe
the process of burning front propagation during an X-ray burst. Our
results show observational evidences of expanding hot-spot with spin
modulated flame speeds, possibly due to the effects of the Coriolis
force present as a result of the high stellar spin (270-620 Hz). This
implies that the flame propagation is latitude-dependent and we
address the factors affecting the detection and non-detection of burst
rise oscillations in the light of this Coriolis force modulated flame
spreading scenario.

contact: Ersin Göğüş ersing@sabanciuniv.edu