Transcript Document

EXTRASOLAR PLANETARY SYSTEMS
DETECTION
METHODS, RESULTS
AN
EASY INTRODUCTION
AND EVERYBODY
PERSPECTIVES
FOR
MICHAŁ RÓŻYCZKA
NICOLAUS COPERNICUS ASTRONOMICAL CENTER
1ST PLANETS SHOOL, HEIDELBERG, OCT. 8TH, 2003
• The first discoveries
• Observing planet formation
• Detecting „mature” planets
• Statistics of extrasolar systems
• Future space missions
THE FIRST
DISCOVERIES
1ST EXTRASOLAR PLANETARY SYSTEM
ANNOUNCED IN JANUARY 1992
ALEX
WOLSZCZAN
2 PLANETS (NOW 3)
1600 LIGHT YEARS FROM THE SUN
CONSTELLATION VIRGO
PSR 1257+12
A
B
C
SUN
DISTANCE (EARTH = 1)
MERCURY
VENUS
EARTH
PSR 1257+12
A
B
C
SUN
DISTANCE (EARTH = 1)
MERCURY
VENUS
EARTH
...
BUT
CERTAINLY
THE
FIRST
... BUT RATHER
SURPRISING
EXTRASOLAR
SYSTEM
:
PROMISING
GLORIOUS...
UNFRIENDLY
1ST PLANET AT A SOLAR-LIKE STAR
ANNOUNCED IN OCTOBER 1995
LONG BEFORE
THAT
MICHEL
MAYOR
STARBIRTH-PROCESSES
DIDIER QUELOZ
HAVE BEEN STUDIED,
YIELDING
CLUES
STAR 51 PEGASI
ABOUT
40 LIGHT YEARS
FROM THE SUN
CONSTELLATION
PEGASUS
PLANET FORMATION
OBSERVING
PLANET FORMATION
(INDIRECTLY)
50 000 LIGHT YEARS
25 000 LIGHT YEARS
1011 STARS
MILKY WAY – STARS ONLY
MILKY WAY – VISIBLE LIGHT
MILKY WAY - INFRARED
CO, 2.64 mm
3-6×109 M
3×105 M
mostly H2
300 l.y.
INFRARED
CO
ORION STAR-FORMING REGION
ORION NEBULA
VISIBLE
2.5 l.y.
INFRARED
ORION
NEBULA
AGE:
A FEW MILLION YEARS
150 objects
R = 50 -1000 AU
M > 600 M
(H2 emission;
absorption of visible light emitted
by the nebula )
M > 2000 M
Concave Disk
b Pictoris
63 l.y.
1.7 M
50 AU
AGE:
108 years
dust mass:
0.1 M
gas mass:
100 M
Infrared 1,2m
resolution 0,12’’
THE
STARS
DISCS
ARE
DISPERSE
BORN
DETAILS
OF
STAR DISC
AND WITHIN
DISC
WITHFORMATION
DISPERSAL
CIRCUMSTELLAR
~ 107 YEARSDISCS
UNKNOWN
RESIDUAL DISCS
SEEM TO CONTAIN
MORE
THAN JUST DUST
A PLANET?
WARP
b Pictoris
FOMALHAUT
25 l.y.
2.8 M
AGE:
108 years
dust mass:
0.1 M
HOLE
HOLE
WARP
OUTER PLANET
INNER
PLANET(S)?
OUTER
PLANET?
INDIRECT EVIDENCE:
PLANETS
RESIDUAL DISCS
CONTAIN
DETECTING
MATURE PLANETS
JUPITER
SHINES WEAKER THAN THE SUN:
1 000 000 000 TIMES
50 000 TIMES
5 000 TIMES
(visible light)
(infrared)
(mm and sub-mm)
JUPITER
OBSERVED FROM THE NEAREST STAR
0.1” DISTANT FROM THE SUN
„DROWNED” IN SUNSHINE !!
PSF, SEEING, ZODIACAL LIGHT, BACKGROUD SKY
REMNANT DISK
AND YET
WITHIN THE LAST 8 YEARS
HOW
??
MORE THAN 110
EXTRASOLAR PLANETS
HAVE BEEN FOUND
POPULAR
VIEW
POPULAR
VIEW
REALITY
X = CENTER
OF MASS
SYSTEM VIEWED
POLE-ON (RARE)
REALITY
SYSTEM VIEWED
OBLIQUELY
(MORE COMMON)
THE PLANET CANNOT BE SEEN
...BUT
MOTIONS
OF THE STAR
BETRAY
ITS PRESENCE !
450 km
9 cm/s
150 000 000 km
30 km/s
X
EARTH
750 000 km
13 m/s
JUPITER
X
780 000 000 km
13 km/s
MOTIONS
OF THE SUN
VIEWED FROM
A STAR 30
LIGHT YEARS
AWAY
2020
1995
2010
1990
0.002’’ IS THE
ANGULAR
SIZE OF A
MAN ON THE
MOON OR A
STANDARD
NEWSPAPER
FONT 300 KM
AWAY
2015
2000
0.002”
2005
STELLAR
WOBBLE
RECEDING:
REDDER
APPROACHING:
BLUER
1 Angstrom = 10-8 cm
PLANET DETECTION DUE TO STELLAR WOBBLE
100
m/s
P
normal to
the orbit
i
to the observer
50
K
0
V
-50
-100
0
1
2 days 3
K = Vsin i
PLANET DETECTION DUE TO STELLAR WOBBLE
MK /(sin i VPL)
MPL sin i = MK / VPL
K = V sin i
KNOWN:
1. ORBITAL PERIOD
2. AMPLITUDE OF VELOCITY VARIATIONS
3. MASS OF THE STAR *
COMPUTED:
1. MASS OF THE PLANET (LOWER LIMIT)
2. ORBITAL RADIUS
ANOTHER
EFFECT:
TRANSIT
PLANET
IN FRONT
OF THE STAR
TRANSIT
BRIGHTNESS
LIGHT
CURVE
1%
TIME
FIRST DETECTION OF A PLANET
VIA THE TRANSIT PHENOMENON
ANNOUNCED IN 2002/2003
ANDRZEJ UDALSKI
MACIEJ KONACKI
STAR OGLE-TR-56
~5000 LIGHT YEARS FROM THE SUN
CONSTELLATION SAGITTARIUS
KNOWN:
1. ORBITAL PERIOD
2. AMPLITUDE OF VELOCITY VARIATIONS
3. MASS OF THE STAR
4. LIGHT CURVE
COMPUTED:
1. MASS1.OF
MASS
THE OF
PLANET
THE PLANET
(LOWER LIMIT)
2. RADIUS AND SHAPE OF THE ORBIT
3. RADIUS OF THE PLANET
BASIC STATISTICS
OF EXTRASOLAR
PLANETS
excentricity e
data from February 2001
b
a
e=(a2-b2)1/2/a
semimajor axis (AU)
ASTRONOMICAL UNITS
COMPOSITE EXTRASOLAR SYSTEM -1
EARTH’S
ORBIT
ASTRONOMICAL UNITS
COMPOSITE EXTRASOLAR SYSTEM -2
ASTRONOMICAL UNITS
MERCURY’S ORBIT
EARTH’S ORBIT
JUPITERS”
„
ASTRONOMICAL UNITS
DEEP INSIDE MERCURY’S ORBIT !!!
Planetary system of u And
0.85 AU
242 days
2 MJ
0.06 AU
4.5 days
0.75 MJ
0.39 AU
89 days
0.73 AU
228 days
1 AU
1 year
2.5 AU
3.5 years
4 MJ
1.54 AU
1.9 years
Solar system
Source: Harvard-Smithsonian CfA
EXPECTED:
NEARLY CIRCULAR ORBITS
BIG PLANETS FAR AWAY FROM THE STAR
NO PLANETS BIGGER THAN JUPITER
DISCOVERED:
STRONGLY ELONGATED ORBITS
BIG PLANETS VERY CLOSE TO THE STAR
MANY PLANETS BIGGER THAN JUPITER
CONCLUSION
ARE
THERE
WHO
WE
ARE:
SOME PLANETARY SYSTEMS
HAVE FORMED
AND/OR EVOLVED
ANY
EARTH-LIKE
ENTIRELYSTANDARD
DIFFERENTLY
COSMIC
PLANETS
THAN THE SOLAR SYSTEM
AT DISTANT
STARS?
OR COSMIC
QUESTIONS:
EXCEPTION?
Distribution of masses of known
extrasolar planets. About 1000 stars have
been surveyed: a nearly complete sample
of solar-type stars within 30 pc.
Occurrence varies inversely with mass.
PLANETS AND METALLICITY
FUTURE
SPACE MISSIONS
RELATED
TO EXTRASOLAR
PLANETS
SIRTF
3.09.2003
INFRARED
This engineering image is a
quick
look at the sky through
LAUNCH:
the Infrared ArrayTH
Camera
AUGUST
(IRAC),
one of 25
three scientific
instruments aboard SIRTF.
The instrument was powered on
for a brief electronics checkout,
and some imagesof the sky
were taken to test whether the
IRAC detectors were
functioning.
The 5 arcmin x 5 arcmin image
was taken in a low Galactic
latitude region in the
constellation Perseus.
PROTOSTARS
PTOTPLANETARY DISCS
COROT, KEPLER, EDDINGTON
LAUNCH
IN 3-5 YEARS
TRANSITS
SEARCH FOR EARTH-LIKE PLANTES
SIM
LAUNCH
IN ~6 YEARS
WOBBLE DUE TO EARTH-LIKE PLANTES
STELLAR MASS ( M)
B
0.01
0.1
ORBITAL PERIOD (YEARS)
10
100
1000
1
10
Main
Sequence
A
habitable zone
F
1
Solar
System
G
K
M
0.1
0.001
Kepler search space
0.01
STELLAR RADIUS
0.1
1
ORBITAL RADIUS (AU )
10
100
DARWIN
INTENSITY
LAUNCH
IN MIN. 11 YEARS
× 1/10 000 cm
DIRECT OBSERVATIONS
OF EARTH-LIKE PLANETS
the
of lifereview
on another
Thediscovery
2001 decadal
of
planet
is potentially
one of the
astronomy
and astrophysics,
most
important
prepared
by thescientific
U.S. National
advances
this century
Researchof
Council,
stated that:
it would have enormous
philosophical implications
IN MORE PRACTICAL TERMS:
PLANETS
ATTRACT
MONEY
LIGHT YEARUNIT
ASTRONOMICAL
1l.y.
= 63000
115000
AUkm
1AU
= 150
13
=
10
km
= 8.3 light minutes