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White Dwarfs, Planets, Disks Marc Kuchner NASA Goddard Space Flight Center Laboratory for Exoplanets and Stellar Astrophysics. Laboratory for Exoplanets and Stellar Astrophysics NASA Postdoctoral Program: http://nasa.orau.org/postdoc/ Exoplanet Talks: http://eud.gsfc.nasa.gov/ - PowerPoint PPT Presentation
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White Dwarfs, Planets, Disks
Marc Kuchner
NASA Goddard Space Flight Center
Laboratory for Exoplanetsand Stellar Astrophysics
Laboratory for Exoplanetsand Stellar Astrophysics
NASA Postdoctoral Program:http://nasa.orau.org/postdoc/
Exoplanet Talks: http://eud.gsfc.nasa.gov/ Marc.Kuchner/exoplanetclub.html
Spitzer Space Telescope
White DwarfBill Reach (IPAC)Ted von Hippel, Don Winget,Mukremin Kilic, Fergal Mullaly(UT Austin)Adam Burrows (U. Arizona)
Wavelength (microns)
White DwarfG29-38
Zuckerman &Becklin 1987
1200 K0.15 Rsun
~40 Jupitermassesby age and T
H
He
CMg
Fe
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log mass (solar masses)
Rad
ius
(Ear
th R
adii)
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White Dwarf
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log mass (solar masses)
Rad
ius
(Ear
th R
adii)
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G29-38b ?
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Jupiter
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DZ
75% 10% 5% 10%
Helium Surface
Hydrogen Surface
No Lines fromSurface!
DQ
DX
Metal, Carbon,Or Unidentified
Carbon andOxygen Core
DA DCDB
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~20% of DAs, including G29-38
Hydrogen Surface with Metals
DAZ
CO core
Teff (K)
Bergeron et al. 2004
DA InstabilityStrip
L
og g
615s
P
ower
23 JUL 1988B-band
24 JUL 1988K-band
Patterson et al. 1991
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Pulsation Timing
(Kleinman et al. 1998) & speckle photometry (Kuchner et al. 1998)
HST/Gemini Photometry
(Debes et al. 2005)
Debes et al. 2005
Log R (AU)
MJu
pite
r
Deuterium Burning Limit
e.g. Debes & Sigurdsson 2002, Jura et al. 2003
Spitzer Space Telescope
White Dwarf
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Jupiter at 5 microns w/ ISO (Encrenaz et al. 1997)
Typical WD ages since formation ofprogenitor are 1.5 - 3.5 109 years.
Planet mass (MJupiter)0 5 10 15
0.3
0.2
0.1
0.0Pla
net/W
D a
t 4.5
mic
rons
109 yr.
3 109 yr.
Spitzer photometry
CIA
Bergeron et al. 1994
Kilic et al. 2006, ApJ, in press
Same Modelsw/ CIA
New Spitzer Photometry
Without the mid IR data:
5400 K, 3.5 Gyr old.
With the mid IR data:
5200 K, 4.5 Gyr old
FJ/FV
F8
m/F
VDZ
All Hydrogen WDs below ~7000 Kshow an 8 micron deficit!
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Galactic Disk:8 +/- 1.5 Gyr
Von Hippel et al., in prep
A New Dusty WD!
Kilic et al. 2005Becklin et al. 2005
Becklin & Zuckerman 1987
Kilic et al., in prepGD 56
Plus 2 more from IRTF and one from Farihi et al makes 5!
Amorphous carbon needed tomatch 1.6 m spectrum
amorphousolivine
forsterite
Reach et al. 2005
C:O ratio 3:11-10RSun
0.01-1000 m grains dn/da a-3.5
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Livio, Pringle & Saffer 1992
H
He
CMg
Fe
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log mass (solar masses)
Rad
ius
(Ear
th R
adii)
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White Dwarf
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C:O ratio in gas 9:1 Roberge et al. in press
11.3 micron C-Hout-of-plane bend
T Tauri Stars -- Spitzer
Geers et al 2005
Particle Plieups Youdin & Chiang 2004
Lodders& Fegley 1997
Wood &Hashimoto1993
Atomic Fraction
SiC
Forsterite
Cohenite
EnstatiteFe
EnstatiteChondrites?
Gas and Graphite
Gaidos 2000Kuchner & Seager 2005
Artist: Lynette Cook
Solar Composition
Kuchner & Seager 2005
Carbon Planet
Kuchner & Seager 2005
Kuchner & Seager 2005
Kuchner & Seager 2005
Tim
e o
f A
rriv
al R
esid
ual
s (
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w/o planets
withnon-interactingplanets
with realplanets
Konacki & Wolzsczan 03
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Cool Hydrogen WDs have mid-IR deficits; the inferred age of theGalactic disk is wrong by ~25%.
Roughly 1/4 DAZ WDs are dusty.
The dust sometimes has silicates----but it may be C rich (e.g. G29-38).
Carbon planets may be common; we can recognize them if they are hot.
Key Points
New Exoplanet Lab at Goddard: come join us as a postdoc or asa speaker!
Wavelength (microns)
Flu
x (m
Jy)
A WD Planet With A Dust Disk
Reach, Von Hippel& Kuchner et al. 2005
Plus one more from Farihi et al. (private comminucation).
That makes 5 dusty DAZs out of 20 DAZs with 8 micronPhotometery.
DAZd ?
New Dusty WDs from IRTF:GD56+GD362(Kilic et al 2006)
GD362 also found byBecklin et al. 2006
The SunGalactic Center
Carigi et al. 2005
Dead Star:White DwarfG 29-38
Solar SystemDust
6 8 10 12 14
Wavelength (microns)
Rel
ativ
e br
ight
ness
Spitzer Sees Ghostof Solar System’sFuture
Marc KuchnerGoddard Space Flight Center
Bill ReachSpitzer Science Center
Ted von HippelUniversity of Texas, Austin
Oppenheimer et al. 2001
Bergeron & Leggett 2002
UltraCool WDs (<4000 K)