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: Exoplanet Talks: Marc.Kuchner/exoplanetclub.html

Spitzer Space Telescope White Dwarf Bill Reach (IPAC) Ted von Hippel, Don Winget, Mukremin Kilic, Fergal Mullaly (UT Austin) Adam Burrows (U. Arizona)

Wavelength (microns) White Dwarf G29-38 Zuckerman & Becklin K 0.15 R sun ~40 Jupiter masses by age and T

H He C Mg Fe x=0.75 log mass (solar masses) Radius (Earth Radii) White Dwarf

log mass (solar masses) Radius (Earth Radii) HD209458b G29-38b ? Jupiter

DO DZ 75% 10% 5% 10% Helium Surface Hydrogen Surface No Lines from Surface! DQ DX Metal, Carbon, Or Unidentified Carbon and Oxygen Core DA DC DB

~20% of DAs, including G29-38 Hydrogen Surface with Metals DAZ CO core

T eff (K) Bergeron et al DA Instability Strip Log g

615s Power 23 JUL 1988 B-band 24 JUL 1988 K-band Patterson et al. 1991

Pulsation Timing (Kleinman et al. 1998) & speckle photometry (Kuchner et al. 1998) HST/Gemini Photometry (Debes et al. 2005) Debes et al Log R (AU) M Jupiter Deuterium Burning Limit

e.g. Debes & Sigurdsson 2002, Jura et al. 2003

Spitzer Space Telescope White Dwarf

Jupiter at 5 microns w/ ISO (Encrenaz et al. 1997)

Typical WD ages since formation of progenitor are  10 9 years. Planet mass (M Jupiter ) Planet/WD at 4.5 microns 10 9 yr. 3  10 9 yr. Spitzer photometry

CIA Bergeron et al. 1994

Kilic et al. 2006, ApJ, in press Same Models w/ 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

F J /F V F 8  m /F V DZ All Hydrogen WDs below ~7000 K show an 8 micron deficit!

Galactic Disk: 8 +/- 1.5 Gyr

Von Hippel et al., in prep A New Dusty WD!

Kilic et al Becklin et al Becklin & Zuckerman 1987 Kilic et al., in prep GD 56 Plus 2 more from IRTF and one from Farihi et al makes 5!

Amorphous carbon needed to match 1.6  m spectrum amorphous olivine forsterite Reach et al C:O ratio 3:1 1-10R Sun  m grains dn/da  a -3.5

Livio, Pringle & Saffer 1992

H He C Mg Fe x=0.75 log mass (solar masses) Radius (Earth Radii) White Dwarf CO Giant

C:O ratio in gas 9:1 Roberge et al. in press

11.3 micron C-H out-of-plane bend T Tauri Stars -- Spitzer Geers et al 2005

Particle Plieups Youdin & Chiang 2004

Lodders & Fegley 1997

Wood & Hashimoto 1993 Atomic Fraction SiC Forsterite Cohenite Enstatite Fe Enstatite Chondrites? Gas and Graphite

Gaidos 2000 Kuchner & Seager 2005

Artist: Lynette Cook

Solar Composition Kuchner & Seager 2005

Carbon Planet Kuchner & Seager 2005

Time of Arrival Residuals (  s) w/o planets with non- interacting planets with real planets Konacki & Wolzsczan 03

Cool Hydrogen WDs have mid-IR deficits; the inferred age of the Galactic 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 as a speaker!

Wavelength (microns) Flux (mJy) 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 micron Photometery. DAZd ?

New Dusty WDs from IRTF: GD56+GD362 (Kilic et al 2006) GD362 also found by Becklin et al. 2006

The Sun Galactic Center Carigi et al. 2005

Dead Star: White Dwarf G Solar System Dust Wavelength (microns) Relative brightness

Spitzer Sees Ghost of Solar System’s Future Marc Kuchner Goddard Space Flight Center Bill Reach Spitzer Science Center Ted von Hippel University of Texas, Austin

Oppenheimer et al. 2001

Bergeron & Leggett 2002 UltraCool WDs (<4000 K)