Download Brown Dwarfs

Brown
Dwarfs
Niels Bos
7 May 2001
Brown Dwarfs
... the facts
Stars
• Big
• Bright
• Hot
• Produce energie
by fusion
&
Planets
?
• Small
• Cool
• Orbit stars
• Produce no
energie
Brown
Dwarfs
Brown Dwarfs
A Brown Dwarf is formed is the
same way as a star, but …
• Is not heavy
enough for nuclear
reactions
• Radiates very faint
in the near-infrared
Brown Dwarfs
Planets & Brown Dwarfs
• Planets are smaller/ lighter
• Planets have a solid core
• They are formed in a
complete different way
Brown
Dwarf
Planet
Brown Dwarfs
... the history
1963
- First indications
1975
- The name ‘Brown
Dwarf’ is suggested
1980`s - Intensive search
1995 -
Brown Dwarfs
... a difficult search
Radiation
• Near-infrared
• Steadily fades in
time
Search near known stars
• Binary system
• Advantages
Search in star-formation clusters
• Brown Dwarfs are brightest
Brown Dwarfs
The Lithium Test
Even the lowest-mass star burns his
lithium in less then 100 million years
Brown Dwarfs
… a new hope
PPI 15
Brown Dwarfs
Brown Dwarfs
… one question
• Can Brown Dwarfs account for a
fraction of the total amount of dark
matter?
Brown Dwarfs
Other questions?