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Trent Dupuy

Warm Spitzer Parallaxes of cool Y dwarfs. Brown dwarfs at ≈ 300 K. Spitzer Space Telescope at ≈ 300 K. Trent Dupuy. Cushing et al. (2011). Adam Kraus ( CfA ) Michael Liu ( IfA /Hawaii). Credit: NASA. Main-sequence stars. parallaxes 2004. >M6. 2012. Brown dwarfs. L.

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Trent Dupuy

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  1. Warm Spitzer Parallaxes of cool Y dwarfs Brown dwarfs at ≈ 300 K Spitzer Space Telescope at ≈ 300 K Trent Dupuy Cushing et al. (2011) Adam Kraus (CfA) Michael Liu (IfA/Hawaii) Credit: NASA

  2. Trent Dupuy (CfA/SAO) Main-sequence stars parallaxes 2004 >M6 2012 Brown dwarfs L dynamical masses 2004 2012 M6−L2 L2.5−L9 L9.5−T4 T4.5−T9 T Dahn et al. (2002); Tinney et al. (2003); Vrba et al. (2003) = dynamical masses Dupuy & Liu (2012)

  3. Trent Dupuy (CfA/SAO) α3d3 Mtot = 0.1095±0.0022 M a3 Mtot = P2 3% distance error  9% mass error Kepler

  4. Trent Dupuy (CfA/SAO) All known ultracool binaries d ≈ 30 pc  need ~1 mas

  5. Trent Dupuy (CfA/SAO)

  6. Trent Dupuy (CfA/SAO) M6−L2 L2.5−L9 L9.5−T4 T4.5−T9 ?

  7. Trent Dupuy (CfA/SAO) OBAFGKMLTY late 1990s 1901 2011

  8. Trent Dupuy (CfA/SAO) Y Dwarfs: A New Frontier 650 K 350 K (Y0) “Y dwarfs: New spectral type? Or spectral hype?” – Travis Barman (Lowell) Cushing et al. (2011)

  9. Trent Dupuy (CfA/SAO) Y Dwarfs: A New Frontier 600 K model 300 K model Lbol ≈ Teff4 We want to measure parallaxes to determine Teffof Y dwarfs.

  10. Trent Dupuy (CfA/SAO) Ground-based observations mostly restricted to near-IR But most flux is emitted in mid-IR models: Burrows, Sudarsky, & Hubeny (2006)

  11. Trent Dupuy (CfA/SAO) Spitzer: Parallax Machine?

  12. Trent Dupuy (CfA/SAO) Why Spitzer hasn’t been used for astrometry Spitzer pixel (1.2”) modern near-IR camera pixel (≈0.3”) parallax ellipse at 10 pc andundersampled (FWHM ≈ 1.4 pix)

  13. Trent Dupuy (CfA/SAO) Why Spitzer hasn’t been used for astrometry 2% Spitzer pixel (1.2”) 2% modern near-IR camera pixel (≈0.3”) scatter in Spitzer distortion solution parallax ellipse at 10 pc

  14. Trent Dupuy (CfA/SAO) newly measured geometric distortion of Spitzer+IRAC Ch1 5th-order polynomial fit to the measured distortion (Kraus et al., in prep.)

  15. Trent Dupuy (CfA/SAO) New Spitzer Parallaxes median precision 17 mas Dt = 2.04 years 100 reference stars

  16. Trent Dupuy (CfA/SAO) other recent results(≈2−4× larger errors) “control” sample

  17. Trent Dupuy (CfA/SAO) Estimating Lbol and Teff evolutionary models give radius estimate Johnson et al. (2011) model @ 450 K Morley et al. (2012) 0.096−0.118 R 0.93−1.15 RJup Teff YJHK plus Spitzer bandpasses contain ≈50%−60% of total flux Lbol

  18. Trent Dupuy (CfA/SAO) At odds with Teff derived from fitting models to near-IR spectra? Cushing et al. (2011) found 350 K.

  19. Trent Dupuy (CfA/SAO)

  20. Trent Dupuy (CfA/SAO) New capability of precise astrometry with Warm Spitzer 1st parallaxes to be measured using only Spitzer data The initial sample of Y dwarfs appear to be warmer than expected (…more tests using color—magnitude diagrams) Parallax precision will improve with longer time baseline in future

  21. Trent Dupuy (CfA/SAO)

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