New Probes of Substellar Evolution from Infrared Parallax Program(s) New Probes of Substellar Evolution from Infrared Parallax Program(s) Trent Dupuy Art

New Probes

of Substellar Evolution

from Infrared Parallax Program(s)

Trent Dupuy

Art credit: R. Hurt (IPAC)

Trent Dupuy (CfA/SAO)

log(L b

ol/L

)

Mass (M)

Hubble Symposium 2012

log(L b

ol/L

)

Saumon & Marley (2008) “hybrid” tracks

Dahn et al. (2002), Tinney et al. (2003), Vrba et al. (2004), etc.

Main-sequence stars

Brown dwarfs Colder = dustier

Colder = more methane-rich

Dust clouds disperse

T

L

energy output= mass

>M6

Hubble Symposium 2012Trent Dupuy (CfA/SAO)

MJ



Main-sequence stars

Brown dwarfs

T

L

>M6

L/T transition

late-T

energy output= mass


MJ



Main-sequence stars

Brown dwarfs

T

L

energy output= mass

>M6dynamical

masses


MJ


Dynamical Masses for Visual Binaries

Kepler

Mtot

a3

P2 =α3d3



log

(Lb

ol/L

)

Mass (M)

10 Gyr

3 Gyr

1 Gyr

0.3 Gyr

0.1 Gyr

T

L

>M6≈3% distance≈10% mass

≈10% distance≈30% mass

starsbrown dwarfs“planetary mass”


Baraffe et al. (2003) COND tracks


USNO opticalPI: Dahn, Monet

Previously published parallaxes for L and T dwarfs

USNO IRPI: Vrba

NTT/SOFIPI: Tinney

Precision needed for ultracool binary masses


Trent Dupuy (CfA/SAO) Hubble Symposium 2012

CFHT Parallax Program - queue scheduled - Mauna Kea seeing - 3.6-m aperture - WIRCam’s large FOV

Credit: J.-C. Cuillandre (CFHT)


10’

WIRCam ObservingStrategy




10’


• use a single chip






• get ≈20−30 dithered frames per epoch





• get ≈20−30 dithered frames per epoch

• J-band: always observe within ≈1 hr of transit (queue is ideal for this)

- OR -• narrow K-band for bright targets – no DCR

differential chromatic refraction

Δairmass < 0.03

Δairmass = 0.2




1. pixel coordinates of sources2. date/time (header)

WIRCam AstrometricAnalysis


• run SExtractor on the detrended images (no stacking!)




• cross-match sources between dithers





Apply custom distortion solution before solving for linear terms.(Also applied differential aberration and refraction offsets: 10-4 change to scale.)



• register dithers without using any catalog info




(i.e., ≈0.04 pixels)(i.e., ≈0.009 pixels)

divide by sqrt(Ndither)



• register dithers without using any catalog info

• compute median and rms of source positions




• Markov Chain Monte Carlo parallax fitter

• orbit motion correction applied to binaries with known orbits

• absolute parallax correction derived from Besancon Galaxy model

• c2 good for all targets, except 3 new astrometric binaries!

Parallax fits for 45 targets(79 objects)



CFHT parallaxes


median: 1.3 mas (2.5%)best: 0.7 mas (1.0%)


Combine new parallaxes with loads of Keck

LGS AO imaging (17 binaries)



And IRTF spectra…

Perform “spectral decomposition” for

all binaries with resolved near-IR photometry and

int.-light spectrum.(33 binaries)




Main-sequence stars

Brown dwarfs


MJ


M6−L2L2.5−L9L9.5−T4T4.5−T9


1. “L/T gap”

2. late-T dwarf diversity 3. J-band brightening

(a.k.a. “bump”)


The L/T “gap”


Paucity of brown dwarfs at certain J-H and J-K colors, but not H-K.

Implies that the last phase of cloud dispersal

occurs rapidly.


The L/T “gap”



The L/T “gap”


Saumon & Marley (2008)

gap pileup

May also be tied to a theoretically predicted (but as yet unobserved)

lag and speed-up in luminosity evolution…


M6−L2L2.5−L9L9.5−T4T4.5−T9


1. “L/T gap”

2. late-T dwarf diversity

Trent Dupuy (CfA/SAO) Hubble Symposium 2012

rms about the polynomial fit in mags

“second” parameters like metallicity, gravity have bigger effect on T dwarfs than for earlier types…


M6−L2L2.5−L9L9.5−T4T4.5−T9


1. “L/T gap”

2. late-T dwarf diversity 3. J-band brightening

(a.k.a. “bump”)


J-band “bump”≈0.7 mag

H-band plateau≈0.0 mag

Y-band “bump”≈0.9 mag

Dust clearing has an even bigger

effect at ≈1.0 mm than at ≈1.2 mm.



Results Summary• CFHT parallaxes (paper 1):

– doubles sample of binaries, ≈tripled L/T transition sample– median (best) precision of 1.3 mas (0.7 mas) or 2.5% (1.0%)– 3 binaries w/ astrometric perturbations (1 new discovery)– Lots of extra data:

• Keck LGS AO + archival HST, VLT imaging• IRTF spectra (spectral decomposition analysis)

• New science with populous sample of ultracool dwarfs:– “L/T gap” observed for the first time– populous late-T sample reveals important 2nd parameters – J-band (and now Y-band) “bump”



High-precisionfor faint targets


1995 2002 20082010

2011

750 K

Gl 570D

700 K700 K

124 K

550 K520 K

350 K

2M0415

CFBDS 0059UGPS 0722

CFBDSIR 1458BWD 0806-661B

Brown Dwarf Discoveries at 300 K?

Extremely cold companion discovered in our Keck LGS AO imaging

Warm Spitzer parallaxes of “room temperature” WISE Y-type dwarfs

Cycle 8 DDT Programco-Is: A. Kraus, M. Liu

Hubble Symposium 2011 @ Caltech(a.k.a. Apple’s next iPhone ad)

Thank You

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New Probes of Substellar Evolution from Infrared Parallax Program(s) New Probes of Substellar Evolution from Infrared Parallax Program(s) Trent Dupuy Art