# Presentation: 787289

## Laboratory for Exoplanets

- Marc Kuchner
- NASA Goddard Space Flight Center
- and Stellar Astrophysics

## Laboratory for Exoplanets

- and Stellar Astrophysics
- NASA Postdoctoral Program:
- http://nasa.orau.org/postdoc/
- Exoplanet Talks:
- _[http://eud.gsfc.nasa.gov/](http://eud.gsfc.nasa.gov/)_
-        Marc.Kuchner/exoplanetclub.html

## Spitzer Space Telescope

*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 1987
- 1200 K
- 0.15 Rsun
- ~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

## 75%                  10%                5%                   10%    

- 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

## Hydrogen Surface 

- ~20% of DAs, including G29-38

- Hydrogen Surface
**with Metals**

**DAZ**

- CO  core

## Teff (K)

- Teff (K)

- Bergeron et al. 2004

- DA
- Instability
- Strip

-    Log g

##            Power            

- 615s

-            Power

- 23 JUL 1988
- B-band

- 24 JUL 1988
- K-band

- Patterson et al. 1991

## Slide 11

## MJupiter

- 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)

- MJupiter

## Slide 13

## Slide 14

## Slide 15

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

## Slide 17

## Spitzer Space Telescope

*Spitzer *Space Telescope

- White Dwarf

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

## Typical WD ages since formation of

- progenitor are 1.5 - 3.5  109 years.

- Planet mass (MJupiter)

- 0                    5                    10                  15

- 0.3
- 0.2
- 0.1
- 0.0

- Planet/WD at 4.5 microns

-    109 yr.

- 3  109 yr.

## Slide 21

**Notes:**
Optical + 2mass + our Spitzer Ddata for the 9 coolest WDs in our sample.

Open circles are synthetic photometry of Didier’s models, normalized at V band.   Lines are same simulation normalized at J band.
Info in parentheses is classifaction of the star from Bergeron and the temperature of the model and the spectral type.

All show some deficit, some show large deficits.
0038 also shows unusual features in optical attributed to C2H molecule, but not yet modeled.

1748 also show big unidentified absorption feature
X in classification means we don’t know what it is.
P means magnetic

## CIA 

- CIA

- Bergeron et al. 1994

**Notes:**
Two mixed H+He models from Didier; these models are the same as Bergeron models shown in corner.  This shows that the models that work in the near IR don’t work in the mid-IR.

(UV data from HST, there’s a problem in the UV because they didn’t include Lyman alpha absorption).

13% of the flux is missing

Without the mid IR data, you think it’s 5400  (3.5 Gyr old).
With the mid IR data, you see that it’s 5200 K (4.5 Gyr old).

Galactic disk is 8 +/- 1.5 Gy based on WD cooling, because the luminosity function peaks at 4000 K, and you don’t see anything cooler except for a handful of ultracool WDs.   Harris et al. 2006 AJ has a new Luminosity function paper.

This age needs to be revised once we get Spitzer data on coolest WDs.

## 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

**Notes:**
Two mixed H+He models from Didier; these models are the same as Bergeron models shown in corner.  This shows that the models that work in the near IR don’t work in the mid-IR.

(UV data from HST, there’s a problem in the UV because they didn’t include Lyman alpha absorption).

13% of the flux is missing

Without the mid IR data, you think it’s 5400  (3.5 Gyr old).
With the mid IR data, you see that it’s 5200 K (4.5 Gyr old).

Galactic disk is 8 +/- 1.5 Gy based on WD cooling, because the luminosity function peaks at 4000 K, and you don’t see anything cooler except for a handful of ultracool WDs.   Harris et al. 2006 AJ has a new Luminosity function paper.

This age needs to be revised once we get Spitzer data on coolest WDs.

##   FJ/FV

-   FJ/FV

- F8m/FV

- DZ

- All Hydrogen WDs below ~7000 K
- show an 8 micron deficit!

**Notes:**
Solid line: H rich atmosphere
Dashed line: He rich atmosphere
Dotted line: blackbody.

All stars with H rich atmospheres have some 8 micron deficit
Only star without 8 microns deficit is he rich (DZ star).

All stars look hotter in the IR.

## Galactic Disk:

- 8 +/- 1.5 Gyr

## A New Dusty WD!

- Von Hippel et al., in prep

**Notes:**
WD 2115, our discovery.

## Plus 2 more from IRTF and one from Farihi et al makes 5!

- Becklin et al. 2005

- Becklin & Zuckerman 1987

- Kilic et al., in prep

- GD 56

## Slide 28

## Slide 29

## Slide 30

## C:O ratio 3:1

- Amorphous carbon needed to
- match 1.6 m spectrum

- amorphous
- olivine

- forsterite

- Reach et al. 2005

- 1-10RSun
- 0.01-1000 m grains
- dn/da  a-3.5

## Livio, Pringle & Saffer 1992 

- 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 

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

## 11.3 micron C-H

**11.3 micron C-H**
**out-of-plane bend**

**T Tauri Stars -- Spitzer**

- Geers et al 2005

## Slide 36

## Slide 37

## Slide 38

## Particle Plieups

**Particle Plieups**

- Youdin & Chiang 2004

## Lodders

- & Fegley 1997

## Wood &

**Wood &**
**Hashimoto**
**1993**

**         ****Atomic Fraction        **

**SiC**

**Forsterite**

**Cohenite**

**Enstatite**

**Fe**

**Gas and Graphite**

## Slide 42

## Gaidos  2000

- Kuchner  & Seager 2005

## Artist: Lynette Cook

## Solar Composition

- Kuchner & Seager 2005

## Carbon Planet

- Kuchner & Seager 2005

## Kuchner & Seager 2005

## Kuchner & Seager 2005

## Time of Arrival Residuals (s)

**w/o planets**

**with**
**non-**
**interacting**
**planets**

**with real**
**planets**

- Konacki & Wolzsczan 03

## Key Points

- 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.

- New Exoplanet Lab at Goddard: come join us as a postdoc or as
- a speaker!

## Slide 51

## Wavelength (microns)

- Flux (mJy)

- A WD Planet With A Dust Disk

- Reach, Von Hippel
- & Kuchner et al. 2005

## Slide 53

## 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 

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

## Slide 56

## The Sun

- Galactic Center

- Carigi et al. 2005

## Dead Star:

- White Dwarf
- G 29-38

- Solar System
- Dust

- 6             8             10           12           14

- 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

**Notes:**
This is Keck IR spectroscopy for some object from Ben Oppenheimer.

You don’t see the CIA obsorption features Bergeron predicted!

Models plotted are blackbodies fitted to UV part of spectrum.

## Slide 61

**Notes:**
Solid line: H rich atmosphere
Dashed line: He rich atmosphere
Dotted line: blackbody.

All stars with H rich atmospheres have some 8 micron deficit
Only star without 8 microns deficit is he rich (DZ star).

All stars look hotter in the IR.

## UltraCool WDs  (<4000 K)

- Bergeron & Leggett 2002

**Notes:**
There are only 2 Ultracool WDs that are well studied in the near IR
(because they are bright enough).  One is LHS 3250 
Cool is< 8000 K. Ultracool is < 4000 K; there are 10 Ultracool WDs.

Sloan has found 7 of the 10 known ultracool WDs. 

Shown is spectroscopy and photometry from Sloan.
Models are from Bergeron, observation are from Leggett.

Figure shows that adding Helium to atmosphere improves fit, but it’s still lousy.

CIA is Hydrogen molecules----same as in cool stars.
In homonuclear molecules, there is no dipole moment, so no rotational or vibrational dipole emission.
Short lived species (H2-H2 or H2-He) are formed that have dipole moments.
These are ro-vibrational spectra from these supermolecules.