New Probes of Substellar Evolution from Infrared Parallax Program(s) New Probes of Substellar Evolution from Infrared Parallax Program(s) Trent Dupuy Art credit: R. Hurt (IPAC)

log(L bol /L  ) Mass (M  ) Hubble Symposium 2012Trent Dupuy (CfA/SAO) log(L bol /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) MJMJ

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 2012Trent Dupuy (CfA/SAO) MJMJ

Dahn et al. (2002), Tinney et al. (2003), Vrba et al. (2004), etc. Main-sequence stars Brown dwarfs T L energy output = mass >M6 dynamical masses Hubble Symposium 2012Trent Dupuy (CfA/SAO) MJMJ

Dynamical Masses for Visual Binaries Kepler M tot a3a3 P2P2 = α3d3α3d3 Hubble Symposium 2012Trent Dupuy (CfA/SAO)

log(L bol /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 2012Trent Dupuy (CfA/SAO) Baraffe et al. (2003) COND tracks

USNO optical PI: Dahn, Monet Previously published parallaxes for L and T dwarfs USNO IR PI: Vrba NTT/SOFI PI: Tinney Precision needed for ultracool binary masses Hubble Symposium 2012Trent Dupuy (CfA/SAO)

Hubble Symposium 2012Trent Dupuy (CfA/SAO) CFHT Parallax Program - queue scheduled - Mauna Kea seeing m aperture - WIRCam’s large FOV CFHT Parallax Program - queue scheduled - Mauna Kea seeing m aperture - WIRCam’s large FOV Credit: J.-C. Cuillandre (CFHT)

10’ WIRCam Observing Strategy Credit: J.-C. Cuillandre (CFHT) Hubble Symposium 2012Trent Dupuy (CfA/SAO)

10’ Credit: J.-C. Cuillandre (CFHT) use a single chip Hubble Symposium 2012Trent Dupuy (CfA/SAO) WIRCam Observing Strategy

Credit: J.-C. Cuillandre (CFHT) use a single chip get ≈20−30 dithered frames per epoch Hubble Symposium 2012Trent Dupuy (CfA/SAO) WIRCam Observing Strategy

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 2012Trent Dupuy (CfA/SAO) WIRCam Observing Strategy

1. pixel coordinates of sources 2. date/time (header) WIRCam Astrometric Analysis Credit: J.-C. Cuillandre (CFHT) run SExtractor on the detrended images (no stacking!) Hubble Symposium 2012Trent Dupuy (CfA/SAO)

run SExtractor on the detrended images (no stacking!) cross-match sources between dithers Credit: J.-C. Cuillandre (CFHT) Hubble Symposium 2012Trent Dupuy (CfA/SAO) WIRCam Astrometric Analysis

Apply custom distortion solution before solving for linear terms. (Also applied differential aberration and refraction offsets: 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 2012Trent Dupuy (CfA/SAO) WIRCam Astrometric Analysis

(i.e., ≈0.04 pixels) (i.e., ≈0.009 pixels) divide by sqrt(N dither ) 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 2012Trent Dupuy (CfA/SAO) WIRCam Astrometric Analysis

Markov Chain Monte Carlo parallax fitter orbit motion correction applied to binaries with known orbits absolute parallax correction derived from Besancon Galaxy model  2 good for all targets, except 3 new astrometric binaries! Parallax fits for 45 targets (79 objects) Hubble Symposium 2012Trent Dupuy (CfA/SAO)

CFHT parallaxes Hubble Symposium 2012Trent Dupuy (CfA/SAO) median: 1.3 mas (2.5%) best: 0.7 mas (1.0%)

Combine new parallaxes with loads of Keck LGS AO imaging (17 binaries) Hubble Symposium 2012Trent 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 2012Trent Dupuy (CfA/SAO)

Dahn et al. (2002), Tinney et al. (2003), Vrba et al. (2004), etc. Main-sequence stars Brown dwarfs Hubble Symposium 2012Trent Dupuy (CfA/SAO) MJMJ

M6−L2 L2.5−L9 L9.5−T4 T4.5−T9 Hubble Symposium 2012Trent Dupuy (CfA/SAO) 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…

M6−L2 L2.5−L9 L9.5−T4 T4.5−T9 Hubble Symposium 2012Trent Dupuy (CfA/SAO) 1. “L/T gap”2. late-T dwarf diversity

Hubble Symposium 2012Trent Dupuy (CfA/SAO) rms about the polynomial fit in mags “second” parameters like metallicity, gravity have bigger effect on T dwarfs than for earlier types…

M6−L2 L2.5−L9 L9.5−T4 T4.5−T9 Hubble Symposium 2012Trent Dupuy (CfA/SAO) 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  m than at ≈1.2  m. Hubble Symposium 2012Trent Dupuy (CfA/SAO)

M6−L2 L2.5−L9 L9.5−T4 T4.5−T9 Hubble Symposium 2012Trent 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 2 nd parameters – J-band (and now Y-band) “bump” Hubble Symposium 2012Trent Dupuy (CfA/SAO)

High-precision for faint targets Hubble Symposium 2012Trent Dupuy (CfA/SAO)

K Gl 570D 700 K 124 K 550 K520 K350 K 2M0415 CFBDS 0059 UGPS 0722 CFBDSIR 1458B WD B 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 Program co-Is: A. Kraus, M. Liu

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