Transcript Interstellar Cloud

Stellar Birth
Nikki B
Karly B
Interstellar Cloud

An accumulation of
dust, gas and plasma
that is a denser-thanaverage region of the
interstellar medium
Collapsing Cloud Fragment
The density of the cloud formed begins to
decrease.
 Photons absorbed by the thin material of
the fragment are radiated into space, so
no temperature increase occurs.
 The fragments continue to contract until
they become so dense that radiation can
not escape the core of the star.

Fragmentation Ceases



Tens of thousands of
years after the second
stage, the fragment
begins to collapse
The center becomes
opaque and the central
temperature rises
significantly
A protostar appears at the
center and the cloud
shrinks to the size of our
solar system
Protostar



A protostar is the center
of the disc formed in the
center of the interstellar
gas cloud.
Hotter than the gas it
condensed, but cooler
than a star.
Further collapse occurs
when the protostar
reaches seven million
Kelvin and nuclear
reactions begin in the
core.
Protostar Evolution

As the protostar moves
beyond stage 4, it becomes a
T Tauri star, moving toward
the main sequence

this path from stage 4 to 6 is
known as the Hayashi track


Characterized by violent
surface activity and strong
protostellar winds
Central temperature is still
not hot enough for
thermonuclear fusion

repulsion of two positively
charged protons (Hydrogen
nuclei) cannot be overcome
Newborn Star



After 100,000 years of
formation, a newborn star
is created.
The temperature of the
newborn star begins to
increase, causing the
fusion of hydrogen to
create helium
The remaining dust and
gas surrounding the star
disperses.
Main Sequence

The star contracts
and comes into
hydrostatic
equilibrium
Works Cited
• http://physics.uoregon.edu/~jimbrau/astr12
2/Notes/Chapter19.html
• http://en.wikipedia.org/wiki/Interstellar_clo
ud
• http://physics.fortlewis.edu/Astronomy/astr
onomy
• http://www.nmm.ac.uk/server/show