Download Fomalhaut b

High‐contrast
op/cal
imaging
with
HST
Direct
detec)on
of
Jupiter
and
Kuiper
Belt
analogs
around
Fomalhaut
Paul
Kalas
UC
Berkeley
&
SETI
Ins)tute
“Op/cal
images
of
an
exosolar
planet
25
light
years
from
Earth”
Kalas
et
al.
2008,
Science,
322,
1345
Collaborators:
James
Graham,
Mark
Clampin,
Mike
Fitzgerald,
Eugene
Chiang,
Edwin
Kite,
Karl
Stapelfeldt,
John
Krist,
Mark
WyaS,
MaS
Kenoworthy,
John
Wisniewski,
Ansgar
Reiners,
Andreas
Seifahrt,
Stefan
Dreizler
1
What
do
Fomalhaut,
Beta
Pic
and
HR
8799
have
in
common?
2
The
A
star
direct‐detec)on
planets
Host
SpT
Dist.
(pc)
Sep.
(AU)
Mass
(MJ)
Age
(Myr)
Reference
Fomalhaut
A3V
7.69
119
<3.0
100
‐
300
Kalas
et
al.
‘08
Beta
Pic
A5V
19.3
8
6
‐
12
8
‐
20
Lagrange
et
al.
‘08
HR
8799
A5V
39.4±1.0
68,
38,
24
5‐11
7‐13
30
‐
160
Marois
et
al.
‘08
AB
Pic
K2
11
‐
25
30
–
40
Chauvin
et
al.
‘05
2M1207
M8
52.4±1.1
54
2
–
25
5
–
12
Chauvin
et
al.
‘04
GQ
Lup
K7
140
±
50
100
4
–
39
<2
Neuhauser
et
al.
‘05
1RXJ1609
29
G
145±20
330
6
–
12
5
Lefreniere
et
al.
‘08
CT
Cha
K7
160±30
440
11
‐
23
<2
Schmidt
et
al.
‘08
47.3±1.8
258
Visible light: Fomalhaut
Orbital motion: Fomalhaut, HR 8799, and GQ Lup
One epoch only β Pic, 1RXJ1609
What is a planet? Formation matters?
Starting early 2011:
Gemini Planet Imager
And SPHERE
3
Debris
disk
stars:
rela)vely
young
107
–
108
yr
Plot shows
nearby stars
with debris
disks
dust
optical
depth
Adapted from
Zuckerman
4
Analogs
to
the
early
solar
system
Strom et al. 2005
t-3 initially,
t-1 in the middle
flat in recent times
note that this for <3 AU
5
Martin et al. 06
Planet
Imaging:
Easy
or
Hard?
Look
at
theore)cal
apparent
magnitude
at
0.8
micron
Star
D
(pc)
Age
(Myr)
Star
(I
band)
1
Jupiter
10
Jupiter
Fomalhaut
7.7
200
1.3
mag
26
mag
22
mag
Vega
7.8
200
0.0
mag
26
mag
22
mag
Beta
Pic
19.3
10
3.8
mag
24
mag
19
mag
Using Burrows et al. models
6
Fomalhaut
7
Fomalhaut
IRAS
excess
star,
but
no
disk
detected
in
scaSered
light
Older
and
less
dusty
than 
Pic
1993: Optical observations from
Mauna Kea (Paul Kalas)
1999: Hubble observations with
WFPC2 (Al Schultz)
mv = 1.3 mag
8
HST
Advanced
Camera
for
Surveys
2002 STS-109
•  High Resolution Channel (HRC)
–  Optimized for NUV band
–  26” x 29” field of view
–  0.025”/pixel plate scale
–  Stellar Coronograph mode
9
Why
target
Fomalhaut
for
an
HST
planet
search?
•  1984
:
IRAS
mission
finds
dust
grains
orbi)ng
Fomalhaut,
as
well
as
other
stars
such
as
Epsilon
Eridani,
Vega,
and
Beta
Pictoris
•  Resolved
thermal
emission
shows
a
central
hole
(Holland
et
al.
1998)
•  Fomalhaut
is
nearby
(7.7
pc).
High
proper
mo)on
(0.4”/yr).
•  Fomalhaut
is
a
young,
main
sequence
star
(200
±
100
Myr).
•  Fomalhaut
planets
are
finished
with
their
forma)on,
but
they
are
s)ll
self‐luminous.
10
2004 Planet Search Using the Advanced Camera for Surveys
Kalas, Graham & Clampin
“A planetary system as the origin of structure in Fomalhaut’s dust belt”
2005, Nature, Vol. 435, pp. 1067
•  No planet found, but dust belt seen for the first time in reflected light
•  Remarkable properties: Not centered on the star and very sharp inner edge
•  Explanation: Gravitational Perturbations by a Planet (Wyatt et al. 1999, Moro-Martin & Malhotra 2002)
Are the
belt’s
brightness
asymmetries
due to
planets?
orbital period at 140 AU = 1200 yr
11
HST ACS planet search
Evidence for a planetary system: Center of symmetry offset
Wyatt et al. 1999
G. Schneider, STIS
How Observations of circumstellar disk
asymmetries can reveal hidden
planets:Pericenter glow and its
application to the HR 4796A disk
Wyatt, M.C. et al. 1999, ApJ, 527, 918
•  Particle eccentricity composed of a
proper (free) eccentricity, inherent to the
particle, and a forced eccentricity due to a
perturber. The pericenter also has a free
and a forced component.
S = stellar position
D = center of particle orbit
C = center of precession circle
P = pericenter of a particle orbit
DP = a, semi-major axis of a particle orbit
wf = direction of forced pericenter
SD = a e
SC = a eforced CD = a eproper
Torus inner radius = a (1 - eproper) = 133 AU
Torus outer radius = a (1+ eproper)
•  The orbital distribution of particles with
common forced elements will be a torus
with center, C, offset from the stellar
position, S.
•  The forcing is due to an eccentric
companion that could be either inside or
outside the belt. HST ACS planet search
Key prediction for a planetary system
Knife-edge inner boundary means that perturber is inside the belt.
Radial cut along 10˚ segment Q2
(apastron), in the illumination corrected
image; cut traces the material surface
density of the structure rather than its
brightness.
Blue line is the model fit:
1) 
Knife-edge inner edge = 133 AU
2) 
n(r) = n(ro) r -9
3) 
Scale height = 3.5 AU at 133 AU
Key prediction for a planetary system
Knife-edge inner boundary means that perturber is inside the belt.
Kuiper Belt dust models by Moro-Martin & Malhotra 2002
radial cuts
planets
1) 
Dust produced by KBOs
a=35-50 AU, i = 0˚-17˚
2) 
1-40 µm, ρ = 2.7 g cm-3 &
3-120 µm, ρ=1 g cm-3
3) 
7 planet, or no planets
4) 
Solar gravity, RP, P-R drag,
solar wind drag.
no planets
5) 
β = RP / gravity ∝
L* / ρ s
2006:
HST/ACS
deep
mul/‐wavelength
imaging
F435W,
F606W,
F814W
15
Fomalhaut
b
2004
Paul
Kalas
(University
of
California,
Berkeley)
16
Fomalhaut
b
2006
Paul
Kalas
(University
of
California,
Berkeley)
17
Fomalhaut
b
2004
Paul
Kalas
(University
of
California,
Berkeley)
18
Fomalhaut
b
2006
Paul
Kalas
(University
of
California,
Berkeley)
19
Background
star?
20
Speckle
Noise?
Confirmed
in
dithered
observa)ons,
two
wavelengths,
two
types
of
PSF
subtrac)on
21
22
Fomalhaut b: Counterclockwise orbit
(below: north up, east left)
24
What
is
the
mass
of
Fomalhaut
b?
From
the
observed
proximity
of
Fom‐b
to
the
belt
inner
edge
(18
AU),
and
the
shape
of
the
radial
dust
profile:
10
MJ
unlikely,
<3.0
MJ
most
probably
See Chiang et al.
2009, Astrophysical Journal, 693, 734
Also, Quillen (2006)
25
What
is
the
mass
of
Fomalhaut
b?
#1 Fom-b is 18 AU from the inner edge of the belt.
Chiang et al. 2009, ApJ, 693, 734
26
What
is
the
mass
of
Fomalhaut
b?
From
the
observed
proximity
of
Fom‐b
to
the
belt
inner
edge
(18
AU),
and
the
shape
of
the
radial
dust
profile:
10
MJ
unlikely,
<3.0
MJ
most
probably
See Chiang et al.
2009, Astrophysical Journal, 693, 734
Also, Quillen (2006)
27
What
is
the
mass
of
Fomalhaut
b?
#2 From how bright it is in the optical, and non-detection in the infrared…. less than 3
Jupiter masses.
Other sources of optical luminosity are possible: glowing hot gas and/or reflected
light from a circumplanetary disk
Teff = 400 K, M = 1.7 – 3.5 MJ
28
adapted
from
Marois
et
al.
08
Fomalhaut b
• Fomalhaut b is the lowest
luminosity object directly
detected outside of our solar
system.
29
Fomalhaut
b
not
detected,
yet,
with
Keck
&
VLT
(1.6
–
2.2
µm)
and
Gemini
(3.8
µm)
L’ (3.8 microns)
Gemini North 8-m
NIRI 22”x22” field
1-σ limit 19 µJy
Michael Fitzgerald (LLNL)
30
Are we seeing a planet or
something else?
31
32
Protogalilean,
circumplanetary
disk
How much flux from star received at Fom-b?
Equivalent to flux received by Neptune
from Sun.
33
How much flux from Fom-b received at Earth?
p = projected geometric surface area of the planet+rings
Qs = scattering efficiency (geometric albedo times phase function at given phase)
Observations:
mv = 25.0 mag
Planet only (1.2 RJ, Qs = 0.5):
Planet + Rings to Roche Radius
Planet + 20 Rp rings (Qs = 0.4)
Planet + 35 Rp rings (Qs = 0.1)
mv = 30.0 mag
mv = 29.5 mag
mv = 25.0 mag
mv = 25.0 mag
For comparison, Callisto at ~27 Jupiter radii
34
Protogalilean,
circumplanetary
disk
Planet
with
16
‐
35
Rp
rings
•  How does it survive 200 Myr?
•  Callisto forms in 1 Myr (Mosqueira &
Estrada 2003)
•  Belt crossing orbit?
•  Planet mass <<3 MJ
35
Summary:
Present
Day
•  HST
has
achieved
a
defini)ve
op)cal
detec)on
of
an
exoplanet
orbi/ng
a
main
sequence
star
at
7.7
pc.
•  Fomalhaut
b
is
between
a
Neptune
and
a
Jupiter
in
mass.
•  Excellent
system
for
detailed
study
the
dynamics
between
planets
and
planetesimals.
•  The
unusual
brightness
of
Fomalhaut
b
at
op)cal
wavelengths
indicates
that
we
may
be
seeing
circumplanetary
dust
rings
reflec)ng
light.
36
Major
Ques/ons:
Fomalhaut,
Beta
Pic,
HR
8799,
et
al.
•  Why
don’t
all
young
A
stars
have
massive,
wide
separa)on
easily
detectable
planets?
•  Inii)al
condi)ons
or
subsequent
evolu)on?
•  Observa)onal
bias,
only
a
few
young
stars
near
the
Sun?
•  Explain
the
configura)on
and
stability
of
our
own
solar
system?
37
Hot
off
the
press
•  MMT
at
5
µm,
no
planets
>2
MJ
between
13
‐
40
AU
–  Kenworthy
et
al.
2009
•  Spitzer
/
IRAC
planet
search:
No
detec)on
of
planets
with
mass
M
>
3.0
MJ
–  Marengo
et
al.
2009
•  VLT
/
AMBER
op)cal
Interferometry
resolves
stellar
photosphere
and
determines
spin

Counterclockwise
–  (Le
Bouquin
et
al.
2009)
•  Fomalhaut
b
can
form
in
situ
via
GI
(Nero
&
Bjorkman
2009)
or
migra)on
that
includes
a
second
planet
(Crida
et
al
2009).
38
39
Fomalhaut b
35 Rp rings (Qs = 0.1)
(Kalas et al. 2008)
Saturn
100 - 200 Rp rings
τperp ~ 10-8 (1 km crater)
(Verbiscer, Skrutskie & Hamilton 2009)
40
Towards
other
Earths
Enhanced
bombardment
of
planetary
satellites
Strom et al. 2005
Take away perspective:
Direct
detec)on
of
first
Earths
and
their
orbits
may
be
due
to
the
detectability
of
circumplanetary
debris
rings.
41
Future Work: 3rd & 4th epochs in 2009, 2010  Orbital analysis.
Keck, VLT (Reiners), Gemini, WFC3, STIS (no ACS coronagraphy)
42
Future Work: 2011 - 2013
Host
Sp
T
Dist.
(pc)
Sep.
(AU)
Mass
(MJ)
Age
(Myr)
Reference
Fomalhaut
A3
V
7.69
119
<3.0
100
‐
300
Kalas
et
al.
‘08
Beta
Pic
A5
V
19.3
8
6
‐
12
8
‐
20
Lagrange
et
al.
‘08
HR
8799
A5
V
39.4±1.0
68,
38,
24
5‐11
7‐13
30
‐
160
Marois
et
al.
‘08
AB
Pic
K2
47.3±1.8
258
11
‐
25
30
–
40
Chauvin
et
al.
‘05
2M1207
M8
52.4±1.1
54
2
–
25
5
–
12
Chauvin
et
al.
‘04
GQ
Lup
K7
140
±
50
100
4
–
39
<2
Neuhauser
et
al.
‘05
1RXJ16092
9
G
145±20
330
6
–
12
5
Lefreniere
et
al.
‘08
CT
Cha
K7
160±30
440
11
‐
23
<2
Schmidt
et
al.
‘08
Direct Detections
Add 100+ rows from GPI
and SPHERE results
Gemini Planet Imager
.berkeley.edu
When:
Where:
Who:
How:
What:
15 months from today
Gemini South
PI’s B. Macintosh & J. Graham
High-order AO with coronagraphy
0.9 – 2.4 µm, mI < 9 mag stars,
polarimetry, R~100 spectroscopy