trent dupuy
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Trent Dupuy
Adam Kraus (CfA)Michael Liu (IfA/Hawaii) Credit: NASA
Warm Spitzer Parallaxes of cool Y dwarfs
Brown dwarfsat ≈ 300 K
Spitzer Space Telescope at ≈ 300 K
Cushing et al. (2011)
Hubble Symposium 2013 Trent Dupuy (CfA/SAO)
= dynamical masses
Main-sequence stars
Brown dwarfs
M6−L2L2.5−L9L9.5−T4T4.5−T9
parallaxes20042012
T
L
>M6
dynamical masses
20042012
Dahn et al. (2002); Tinney et al. (2003); Vrba et al. (2003)Dupuy & Liu (2012)
Kepler
Mtota 3
P 2
α 3 d 3
=
3% distance error
9% mass error
Hubble Symposium 2013 Trent Dupuy (CfA/SAO)
Mtot = 0.1095±0.0022 M
d ≈ 30 pc need ~1 mas
Hubble Symposium 2013 Trent Dupuy (CfA/SAO)
All known ultracool binaries
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
M6−L2L2.5−L9L9.5−T4T4.5−T9
?
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
O B A F G K M LT Y1901 late
1990s 2011
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
Y Dwarfs: A New Frontier
650 K350 K
Cushing et al. (2011)“Y dwarfs: New spectral type? Or spectral hype?” – Travis Barman (Lowell)
(Y0)
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
Y Dwarfs: A New Frontier
600 K model300 K model
Lbol ≈ Teff4
We want to measure parallaxes to determine Teff of Y dwarfs.
Trent Dupuy (CfA/SAO)
Ground-based observations mostly restricted to near-IR
But most flux is emitted in mid-IR
Hubble Symposium 2013
300 K 500 K < 1 μmYJHKW1+W2W3+W4> 26 μm
700 K 900 K
models: Burrows, Sudarsky, & Hubeny (2006)
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
Spitzer: Parallax Machine?
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
Spitzer pixel (1.2”)
modern near-IRcamera pixel (≈0.3”)
parallax ellipse at 10 pc
Why Spitzer hasn’t been used for astrometry
and undersampled(FWHM ≈ 1.4 pix)
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
2% modern near-IRcamera pixel (≈0.3”)
parallax ellipse at 10 pc
scatter in Spitzer distortion solution
2% Spitzer pixel (1.2”)
Why Spitzer hasn’t been used for astrometry
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
newly measured geometric distortion of Spitzer+IRAC Ch1
(Kraus et al., in prep.)
5th-order polynomial fit to the measured distortion
New Spitzer Parallaxesmedian precision 17 mas
Dt = 2.04 years100 reference stars
Hubble Symposium 2013 Trent Dupuy (CfA/SAO)
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
“control” sample
other recent results(≈2−4× larger errors)
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
evolutionary models give radius estimate
YJHK plus Spitzer bandpasses contain ≈50%−60% of total flux
Lbol
Estimating Lbol and Teff
0.096−0.118 R0.93−1.15 RJup
Teff
Johnson et al. (2011)model @ 450 K
Morley et al. (2012)
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
Spec. Type
mean Teff (K)
meanlog Lbol
T8 670 −5.7
T8.5 560 −6.0
T9 530 −6.1
Y0 420 −6.5
At odds with Teff derived from fitting models to near-IR spectra? Cushing et al. (2011) found 350 K.
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
Trent Dupuy (CfA/SAO)Hubble Symposium 2013
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
Trent Dupuy (CfA/SAO)Hubble Symposium 2013