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
Trent Dupuy (CfA/SAO)
Dahn et al. (2002), Tinney et al. (2003), Vrba et al. (2004), etc.
Main-sequence stars
Brown dwarfs
T
L
>M6
L/T transition
late-T
energy output= mass
Hubble Symposium 2012
MJ
Trent Dupuy (CfA/SAO)
Dahn et al. (2002), Tinney et al. (2003), Vrba et al. (2004), etc.
Main-sequence stars
Brown dwarfs
T
L
energy output= mass
>M6dynamical
masses
Hubble Symposium 2012
MJ
Trent Dupuy (CfA/SAO)
Dynamical Masses for Visual Binaries
Kepler
Mtot
a3
P2 = α3d3
Hubble Symposium 2012
Trent Dupuy (CfA/SAO)
log(L b
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”
Hubble Symposium 2012
Baraffe et al. (2003) COND tracks
Trent Dupuy (CfA/SAO)
USNO opticalPI: Dahn, Monet
Previously published parallaxes for L and T dwarfs
USNO IRPI: Vrba
NTT/SOFIPI: Tinney
Precision needed for ultracool binary masses
Hubble Symposium 2012
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)
Trent Dupuy (CfA/SAO)
10’
WIRCam ObservingStrategy
Credit: J.-C. Cuillandre (CFHT)
Hubble Symposium 2012
Trent Dupuy (CfA/SAO)
10’
Credit: J.-C. Cuillandre (CFHT)
• use a single chip
Hubble Symposium 2012
WIRCam ObservingStrategy
Trent Dupuy (CfA/SAO)
Credit: J.-C. Cuillandre (CFHT)
• use a single chip
• get ≈20−30 dithered frames per epoch
Hubble Symposium 2012
WIRCam ObservingStrategy
Trent Dupuy (CfA/SAO)
• use a single chip
• 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
Hubble Symposium 2012
WIRCam ObservingStrategy
Trent Dupuy (CfA/SAO)
1. pixel coordinates of sources2. date/time (header)
WIRCam AstrometricAnalysis
Credit: J.-C. Cuillandre (CFHT)
• run SExtractor on the detrended images (no stacking!)
Hubble Symposium 2012
Trent Dupuy (CfA/SAO)
• run SExtractor on the detrended images (no stacking!)
• cross-match sources between dithers
Credit: J.-C. Cuillandre (CFHT)
Hubble Symposium 2012
WIRCam AstrometricAnalysis
Trent Dupuy (CfA/SAO)
Apply custom distortion solution before solving for linear terms.(Also applied differential aberration and refraction offsets: 10-4 change to scale.)
• run SExtractor on the detrended images (no stacking!)
• cross-match sources between dithers
• register dithers without using any catalog info
Hubble Symposium 2012
WIRCam AstrometricAnalysis
Trent Dupuy (CfA/SAO)
(i.e., ≈0.04 pixels)(i.e., ≈0.009 pixels)
divide by sqrt(Ndither)
• run SExtractor on the detrended images (no stacking!)
• cross-match sources between dithers
• register dithers without using any catalog info
• compute median and rms of source positions
Hubble Symposium 2012
WIRCam AstrometricAnalysis
Trent Dupuy (CfA/SAO)
• 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)
Hubble Symposium 2012
Trent Dupuy (CfA/SAO)
CFHT parallaxes
Hubble Symposium 2012
median: 1.3 mas (2.5%)best: 0.7 mas (1.0%)
Trent Dupuy (CfA/SAO)
Combine new parallaxes with loads of Keck
LGS AO imaging (17 binaries)
Hubble Symposium 2012
Trent Dupuy (CfA/SAO)
And IRTF spectra…
Perform “spectral decomposition” for
all binaries with resolved near-IR photometry and
int.-light spectrum.(33 binaries)
Hubble Symposium 2012
Trent Dupuy (CfA/SAO)
Dahn et al. (2002), Tinney et al. (2003), Vrba et al. (2004), etc.
Main-sequence stars
Brown dwarfs
Hubble Symposium 2012
MJ
Trent Dupuy (CfA/SAO)
M6−L2L2.5−L9L9.5−T4T4.5−T9
Hubble Symposium 2012
1. “L/T gap”
2. late-T dwarf diversity 3. J-band brightening
(a.k.a. “bump”)
Trent Dupuy (CfA/SAO)
The L/T “gap”Hubble Symposium 2012
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.
Trent Dupuy (CfA/SAO)
The L/T “gap”Hubble Symposium 2012
Trent Dupuy (CfA/SAO)
The L/T “gap”Hubble Symposium 2012
Saumon & Marley (2008)
gap pileup
May also be tied to a theoretically predicted (but as yet unobserved)
lag and speed-up in luminosity evolution…
Trent Dupuy (CfA/SAO)
M6−L2L2.5−L9L9.5−T4T4.5−T9
Hubble Symposium 2012
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…
Trent Dupuy (CfA/SAO)
M6−L2L2.5−L9L9.5−T4T4.5−T9
Hubble Symposium 2012
1. “L/T gap”
2. late-T dwarf diversity 3. J-band brightening
(a.k.a. “bump”)
Trent Dupuy (CfA/SAO)
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.
Hubble Symposium 2012
Trent Dupuy (CfA/SAO)
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”
Hubble Symposium 2012
Trent Dupuy (CfA/SAO)
High-precisionfor faint targets
Hubble Symposium 2012
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