By studying the corkscrewed expulsion from R Sculptoris, the astronomers calculated that the star was shedding more mass during thermal pulses
than had been estimated.
Section c-d shown in the figure represents the moment after the gas volume has reached the maximum temperature due to the heat transfer from the thermal pulse
and starts cooling off.
Platina Energy Group Inc., through its Permian Energy International subsidiary, has shipped one of its proprietary Thermal Pulse
Units to Billing, Mont.
But in the AGB stars some of the reactions are episodic, occurring only when enough nuclear fuel has collected and heated to "ignite." These episodes are called thermal pulses
. They're believed to occur in all AGB stars at least a few times before the star finally sheds its outer layers and becomes a planetary nebula and a white dwarf.
Some design software tools and energy simulation programs use a similar g- function based approach but often with a greater number of thermal pulses
(Hellstrom and Sanner (1994), Spitler (2000), Fisher et al (2005), Liu and Hellstrom (2006)).
These three terms can be regarded as three consecutive ground thermal pulses
[q.sub.y], [q.sub.m], and [q.sub.h] each multiplied by their respective effective ground thermal resistance [R.sub.y] [R.sub.m], and [R.sub.h].
The device contains a copper alloy-based heat sink that helps manage temperature and an automated control system, to regulate the force and timing of the thermal pulses
that reach the heat sink.
As illustrated in Figure 1, Equation 1 is based on the worst-case scenario represented by three successive thermal pulses
with durations corresponding to 10 years, one month, and six hours.
"In the normal transition from red giant to white dwarf, a star undergoes thermal pulses
with fairly high luminosity, which could lead to the evaporation of the planet."
As I followed the initial coverage of the tsunami in the Indian Ocean, I was reminded of a time in the early1980s when I spent some months researching the effects of a nuclear war--the thermal pulses
from the detonations, the bursts of radiation, the blast waves spreading out from ground zero, the immediate local fallout and the delayed stratospheric fallout.
The values of [R.sub.y], [R.sub.m], and [R.sub.h] represent effective thermal resistances for three thermal pulses
. The periods of these pulses are problem dependent.
Theoretical models predict long-term "thermal pulses
" for Mira-like stars, Kaper notes.