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

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

2. Trent Dupuy (CfA/SAO) log(Lbol/L) log(Lbol/L) Mass (M) Saumon & Marley (2008) “hybrid” tracks

3. Trent Dupuy (CfA/SAO) energy output =mass >M6 Main-sequence stars Colder = dustier Brown dwarfs Dust clouds disperse L MJ T Colder = more methane-rich Dahn et al. (2002), Tinney et al. (2003), Vrba et al. (2004), etc.

4. Trent Dupuy (CfA/SAO) energy output = mass >M6 Main-sequence stars Brown dwarfs L L/T transition MJ T late-T Dahn et al. (2002), Tinney et al. (2003), Vrba et al. (2004), etc.

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

6. Trent Dupuy (CfA/SAO) Dynamical Masses for Visual Binaries α3d3 a3 Mtot = P2 Kepler

7. Trent Dupuy (CfA/SAO) “planetary mass” brown dwarfs stars >M6 ≈3% distance ≈10% mass log(Lbol/L) L ≈10% distance ≈30% mass 0.1 Gyr 0.3 Gyr T 1 Gyr 3 Gyr 10 Gyr Mass (M) Baraffe et al. (2003) COND tracks

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

9. Trent Dupuy (CfA/SAO) CFHT Parallax Program - queue scheduled - Mauna Kea seeing - 3.6-m aperture - WIRCam’s large FOV Credit: J.-C. Cuillandre (CFHT)

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

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

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

13. Trent Dupuy (CfA/SAO) differential chromatic refraction WIRCam Observing Strategy Δairmass < 0.03 • use a single chip • get ≈20−30 dithered frames per epoch • J-band: always observewithin ≈1 hr of transit (queue is ideal for this) • - OR - • narrow K-band for bright targets – no DCR Δairmass = 0.2

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

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

16. Trent Dupuy (CfA/SAO) WIRCam Astrometric Analysis 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

17. Trent Dupuy (CfA/SAO) WIRCam Astrometric Analysis 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 (i.e., ≈0.04 pixels) (i.e., ≈0.009 pixels)

18. Trent Dupuy (CfA/SAO) Parallax fits for 45 targets (79 objects) • 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!

19. Trent Dupuy (CfA/SAO) CFHT parallaxes median: 1.3 mas (2.5%) best: 0.7 mas (1.0%)

20. Trent Dupuy (CfA/SAO) Combine new parallaxes with loads of Keck LGS AO imaging (17 binaries)

21. Trent Dupuy (CfA/SAO) And IRTF spectra… Perform “spectral decomposition” for all binaries with resolved near-IR photometry and int.-light spectrum. (33 binaries)

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

23. Trent Dupuy (CfA/SAO) 2. late-T dwarf diversity 1. “L/T gap” 3. J-band brightening (a.k.a. “bump”) M6−L2 L2.5−L9 L9.5−T4 T4.5−T9

24. Trent Dupuy (CfA/SAO) 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.

25. Trent Dupuy (CfA/SAO) The L/T “gap”

26. Trent Dupuy (CfA/SAO) The L/T “gap” May also be tied to a theoretically predicted (but as yet unobserved) lag and speed-up in luminosity evolution… gap pileup Saumon & Marley (2008)

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

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

29. Trent Dupuy (CfA/SAO) 2. late-T dwarf diversity 1. “L/T gap” 3. J-band brightening (a.k.a. “bump”) M6−L2 L2.5−L9 L9.5−T4 T4.5−T9

30. Trent Dupuy (CfA/SAO) Y-band “bump” ≈0.9 mag Dust clearing has an even bigger effect at ≈1.0 mm than at ≈1.2 mm. J-band “bump” ≈0.7 mag H-band plateau ≈0.0 mag

31. 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”

32. Trent Dupuy (CfA/SAO) High-precision for faint targets

33. Brown Dwarf Discoveries at 300 K? 750 K 700 K 550 K 520 K 350 K Gl 570D 2M0415 Extremely cold companion discovered in our Keck LGS AO imaging 700 K CFBDS 0059 UGPS 0722 CFBDSIR 1458B WD 0806-661B 124 K 2008 1995 2002 2011 2010

34. Warm Spitzer parallaxes of “room temperature” WISE Y-type dwarfs Cycle 8 DDT Program co-Is: A. Kraus, M. Liu

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