Transcript The IR Universe

The Universe in the Infrared
So, what amazing, astounding new
science have we learned with Spitzer?
Images courtesy NASA/JPL - Caltech
Funded by NASA’s Spitzer Science Center
Outline
Solar System
Nearby stars
Protostars and protoplanetary
disks
Galaxies
The distant Universe
The Universe in the Infrared
Pilachowski / August 2005 Slide 2
Comet Debris Tails @ 24 mm
Comets can have 3 types of
tails
gas
dust
debris tails
Debris tails are formed
from mm to cm sized
particles shed by the comet
Debris tails follow the
orbit of the comet
These are the particles
that produce meteor
showers
Daniel Kirkwood!
The Universe in the Infrared
Pilachowski / August 2005 Slide 3
Vega and Fomalhaut
• Debris disks around
nearby stars
– both about 25 LY
• Vega’s is huge
– Seen face-on
– 20 times larger than
the Solar System
– Mass 1/3 of Moon’s
– Recent collision of
Pluto-sized objects?
• Fomalhaut’s is seen
edge-on
The Universe in the Infrared
Pilachowski / August 2005 Slide 4
Alien Asteroid Belt
• A dusty asteroid belt
circling the star HD
69830
• Detected from IR
emissions from dust
• 25 x the mass of our
own asteroid belt
• Or is it a super-comet
(Pluto-sized?)
– forsterite grains like
Hale-Bopp
Artist’s conception
The Universe in the Infrared
Pilachowski / August 2005 Slide 5
Planets Circling a Brown Dwarf?
• OTS 44 is a brown dwarf
– too faint to see in visible light
– intermediate between a star and a planet
– 15 x mass of Jupiter
• Encircled by a dust disk
• Could it harbor planets?
The Universe in the Infrared
Pilachowski / August 2005 Slide 6
Massive Star Embryos Hidden in Dust
 Spitzer sees stars forming inside knots of cold dust
 Infalling material warms, and glows in the infrared
The Universe in the Infrared
Pilachowski / August 2005 Slide 7
How Stars Form
Stars form when huge clouds of gas
and dust collapse due to gravity

When the center
becomes hot and
dense enough, it
blows away the
cocoon, revealing
the new star
inside

At infrared
wavelengths, we
can see inside
the cocoon as
the star forms
The Universe in the Infrared
Pilachowski / August 2005 Slide 8
A Surprise from Spitzer
Left: optical sky survey
image
Right: Spitzer 3-color
composite:
• Blue = 3.6 mm
• Green = 8.0 mm
• Red = 24 mm
L1014 is 600 LY
distant in the
constellation
Cygnus
The central yellow “star” in the center is a
faint, forming star, possibly a brown dwarf.
The Universe in the Infrared
Pilachowski / August 2005 Slide 9
The Elephant Trunk:
A Nearby Star-Forming Region
IR composite image
Spitzer reveals protostars
forming in the Elephant
Trunk Nebula
far infrared image
visible
2,450 LY in Cepheus
The Universe in the Infrared
hot young protostars
embedded in dust
Pilachowski / August 2005 Slide 10
A New Milky Way Globular Cluster
Toward the constellation Aquila
Distance: 9000 LY
The Universe in the Infrared
Age: ~ 13 Gyr
Mass: 300,000 MSun
Pilachowski / August 2005 Slide 11
Milky Way Twin: NGC 7331
The Universe in the Infrared
Pilachowski / August 2005 Slide 12
Distant, Dusty Galaxies
Spitzer has found optically invisible galaxies so distant that we see
them as they were only 3 billion years after the Big Bang. These
galaxies are obscured by silicate dust, suggesting that planets could
have formed even at this early time in the history of the Universe.
Higdon et al. 2005, Ap.J., 626, 58
The Universe in the Infrared
Artist’s conception
Pilachowski / August 2005 Slide 13
Even more distant galaxies…
At even greater
distance, only 2 Gyr
after the Big Bang,
Spitzer finds supermassive black holes in
galaxies shrouded in
dust.
X-rays from some of
these black hole
galaxies are seen with
the Chandra X-ray
telescope, but they
give off too little
visible light to be seen
with Hubble.
The Universe in the Infrared
Pilachowski / August 2005 Slide 14
Spitzer Continues to Amaze!
The Universe in the Infrared
Pilachowski / August 2005 Slide 15