white dwarfs, planets, disks marc kuchner nasa goddard space flight center

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)