Alycia J. Weinberger - Carnegie DTM

Star and Planet Formationwith the GMT

What sets the stellar/substellar mass function andhow universal is it?Do all stars form planets and if not, why not?What causes the diversity of planetary systems?

Weinberger - 6/14/2010

Nearby Star Forming Regions

Good News: Most are in the South Bad News: All are >100 pc away

Ophiuchus -24δ 120 pc ≤1 Myr Lupus -38δ 100 pc ≤ 1 Myr Corona Aust -37δ 170 pc ≤ 1 Myr Chamaeleon -77δ 170 pc 2.5 Myr Upper Sco -30δ 140 pc 5 Myr

4 AU at 150 pc = 27 mas (separate “inner” and “outer”Solar System)

Diffraction limit (λ/D) of GMT at 1.6 µm is 13 mas

Weinberger - 6/14/2010

106 yrs 107 yrs 108 yrs 109 yrs

CAI /ChondruleFormation

Moonforming

Impact (30+ Myr)

Current age ofthe Sun:

4.5x109 yrs.

Late HeavyBombardment

(600 Myr)

Star-formationto solidformation

Massive,gas-richdisk

Planetesimaldominateddisk Dust / planet

dominated diskGas Removal

Giant planetsform

Terrestrialplanets

form

Planetary Formation Timescales

Astronomer’st0

Alycia Weinberger 2009

Weinberger - 6/14/2010

Stellar and Disk Co-Evolution

(Tom Greene)

Weinberger - 6/14/2010

Embedded protostar with disk

1 100 Log(λ) [µm]

Log

(Flu

x D

ensi

ty)

Flat spectrum and/or “Class I”

Log

(Flu

x D

ensi

ty)

Class II

Want to learn simultaneously about the star and its disk

1 100 Log(λ) [µm]

Weinberger - 6/14/2010

Initial Mass Function and Disks

•How many stars/brown dwarfs arethere?•Do they have disks?•Is the disk lifetime the same as forstars?

Example: OphiuchusSize: ~7 X 7 Deg (cloud core plusextended region) GMACS FOV: 8 x 18’ NIRMOS FOV:5.5 x 5.5’

IMACS limiting magnitudeI~21.5, S/N=30, in 4 hr @ R~2000

10-4 Lsun or 3- 5MJ15% too faint (>21.5) for IMACS

IMACS 12x12’ (Gully-Santiago)

Weinberger - 6/14/2010

Initial Mass Function in Star Form. Reg.1 MJ object = 840 K, i.e. T dwarf, with K~19

~1 hr at R~400 with GMT

(Knapp et al. 2004)

Weinberger - 6/14/2010

Astrophysics of Young Stars

Log (Teff)

log

g

(Doppmann et al. 2005)

Keck 0.3-2 hr /source a R~18,000

A wide range ofluminosities andgravities (andtherefore ages)appear for stars of alltypes

Weinberger - 6/14/2010

Stellar Magnetic FieldsDisk evolution is supposedly magnetically drivenOnly a handful of stars have directly measured fields

(Johns-Krull et al. 2009)

Measure Zeeman splitting (or broadening) of lines such as Ti I.

Weinberger - 6/14/2010

Direct Observations of CircumstellarDisks and origins of the diversity ofplanetary systems

Disk Spectroscopy Direct measurement of gas content and

temperature High spectral resolution proxy for spatial

resolution (gas close to the star moves fast) High spatial resolution to resolve the disk directly

(Spectroastrometry) Disk Imaging

Direct measurement of structure Composition from low-resolution spectroscopy of

emitted and scattered light

Weinberger - 6/14/2010

Origin of Isotope Ratios

CO self-shielding: Lyons & Young (2005) suggestedthat irradiation of our young disk generated our18O/17O/16O ratios

Need O to be incorporated into water

(R. Smith et al. 2009)

Weinberger - 6/14/2010

Where is ice line / where is the water?

Giant planets mayform more efficientlyoutside the ice-line

Water-richplanetesimals fromoutside the ice-linemay deliver water todry inner planets

Salyk et al. 2008, ApJLNIRSPEC, R~25,000

Weinberger - 6/14/2010

What are gas densities in planet region?

“Spectroastrometry” Analogous to centroiding to

0.01 pixel Find gas within 1/100 of a

spatial resolution element(~0.3 mas for VLT, 0.1 masfor GMT)

Requires S/N>100 oncontinuum and resolving linekinematically

Need aperture for low lineflux sources: detections are10-16 - 10-17 W/m2

Need excellent calibration inhigh continuum/line sources

Pontoppidan et al. 2008, ApJ, 684, 1323VLT CRIRES+AO, Tint=32 min, R~100K

S/N=280

-30 -20 -10 0 10 20 30 Velocity [km/s]

Weinberger - 6/14/2010

Effect ofCompanions?

Disk is transitional•Contains gas

Scattered Light• Large extent (400 AU)• Red visible – near-IR color

HD 141569A

Mid-IR Emission•Compact extent•PAHs

Star: A0, 16.5 L, 5 Myr old

(Weinberger et al. in prep)

Weinberger - 6/14/2010

Spatially resolved disk kinematics

AO allows disk rotationcurves Combined constraint of

kinematics and size Consider the relevant

scales GMT DL at 5 µm = 0.″04 Closest sites of ongoing

star formation - 150 pc;GMT probes 6 AU (aboutwhere Jupiter formed) Goto et al. 2006, ApJ, 652, 758

Subaru IRCS+AO, Tint=20 min, R~20K

When do planets form?When does gas in inner diskdisappear?

Weinberger - 6/14/2010

Spatially Resolved Spectra of Emission

Terr

estr

ial O

3

Central Disk Spectrum24 AU (0.’’24)

168 AU (1.’’68)

• • •

192 AU (1.92 AU) - Backgd

(Rainbow step every 24 AU)

Weinberger et al. in prep

~1.5 hr at Keck

Weinberger - 6/14/2010

Where are the silicates?

•Hidden under carbon? This explains red colortoo.

PAH+SilicatePAH+AmorphousCarbon+BB

Weinberger et al. in prep

Weinberger - 6/14/2010

Imaging Ices

(Inoue et al. 2008)

Imaging of scattering from water ice in disks

mJy/sq.arcsec

Honda et al. 2009)

HD 142527

Weinberger - 6/14/2010

Watchng planet formation

335 yr

339 yr

346 yr

If planets form bygravitational instability(Boss 1997), spiralarms in disk may beobservable inscattered light.

Need high contrast innear-infrared: 10-7 to10-9

(Jang-Condell & Boss 2007)

10 mas 30 mas

Weinberger - 6/14/2010

Observing planets in disks

(Jang-Condell & Kuchner 2010)

It should bepossible todetect planetsforming in theouter parts ofclassical TTauri stardisks

Weinberger - 6/14/2010

Planet Spectroscopy

GMTIFS offset to “planet” location. Usespatial information to correct for scatteredlight at each wavelength. Preferable to longslit.

McElwain et al. 2008Keck, OSIRIS

Weinberger - 6/14/2010

Spectra of Young Exosolar Planets

Tiger

Fomalhaut planetappearsdominated by ascattered lightdisk. Could learnabout both.

(Kalas et al. 2008)

Weinberger - 6/14/2010

Detecting Planets in Debris Disks

Figure Credit: Chris Stark (U MD)

Weinberger - 6/14/2010

Uses of 1st Generation Instruments forstar and planet formation studies

•GMTNIRS - Probing stellar astrophysics, disk kinematics and composition•Tiger / ExAOCam - Imaging disks and planets in disks, composition

•GMTIFS - Imaging young planets, disks•GMTNIRS / GMACS - Finding brown dwarfs in star forming regions•GCLEF - Debris disk gas, kinematics

GMT will enable many creative projects not envisioned yetand like each generation of large telescope, enablequalitative leaps in measurement ability.