Galactic Star Formation Science

Galactic Star Formation Science

with Integral Field Spectroscopy

Tracy Beck, STScI

Galactic Star Formation Science

with Integral Field Spectroscopy

• Introduction to the formation of sun-like stars in the Milky Way

• Studies of star formation (SF) with IFUs– First uses of IFUs for SF science– Herbig Haro Objects– Young Star Binaries

• Star Formation at high contrast with IFUs: A Search for IR H2 Emission from the Disks of Young Stars

• Cutting Edge Science: Laser-Fed AO IFU spectroscopy of young stars

• Prospects for JWST and the ELTs

Formation of Sun-like Stars in the Milky Way

Sub-mm continuum of protostellar cores

Shirley et al. (2000)

Formation of Sun-like stars in the Milky Way

Young stars with Circumstellar disks + extended Envelopes (“Class I” Protostars)

HST NICMOS Imaging of Protostars (Padgett et al. 1999)


Young stars with Circumstellar disks, no envelope material left (“Class II” Protostars,

“Classical” T Tauri Stars)

Orion ProplydsO’Dell & Wen (1994)


Dust disk dissipates in <1Gyr timescale

Meyer et al. (2008)

Beta Pic Debris Disk


“Class II” Protostars with Disks + Outflows – “Classical T Tauri Stars”

IFUs in Star Formation Science

Herbst et al. “A Near-Infrared Spectral Imaging Study of T Tau” 1996 AJ v.111, 2403

MPE 3D w/ Calar Alto (3.5m)H and K-band

Observations of T Tau

8”

IFUs in Star Formation Science

Lavalley et al. “Sub-arcsecond morphology and kinematics of the DG Tauri jet in the [O I]λ6300 line” 1997 A&A v.327, 671

IFUs are very powerful tools for spatially resolving emission line structures in the environments of bright T Tauri Stars

Herbig Haro Objects

• HH Objects: – optical/infrared tracers of YSO jets, seen where

jets from young stars plow into ambient cloud material and shock the gas into emission

– Pure emission line objects – viewed in optical/infrared permitted and

forbidden transitions – H, [O I], [N II], [S II], [FeII], trace atomic gas excited by shocks

– Shock-excited H2 emission in the IR Natural IFU Sources

Beck et al. 2004, 2007, Lopez et al. 2008, 2010 Giannini et al. 2008

HH 111

HH 46/47

Herbig Haro Objects

• HH 99B: – Very sensitive VLT + SINFONI

observations– 170+ Emission lines detected– Many very high excitation

lines of H2 and [Fe II]– Bow-shock apex shows

extremely high temperature - T~6000K - revealing that the H2 molecule persists in these very high temperature regions

Giannini et al. “Near-infrared, IFU spectroscopy unravels the bow-shock HH99B“ 2008, A&A v.481, 123

H2 1-0 S(1) 2.12m H2 2-1S(17) 1.758m

[Fe II] 1.644 m [Fe II] 1.749 m

[P II] 1.188 mHI Pa 1.28 m

Head of the Bow Shock

Wings of the Bow Shock

Young Star Binaries

• Most stars (50-60%) form as binary or higher order multiple systems

• Understand young star binary characteristics, particularly disk and mass accretion evolution

• The more massive primary star often has more active mass accretion, indicating a larger circumstellar disk reservoir of mass. I.e., preferential accretion from circumsystem material onto the more massive star in a binary

• Spatially Resolved Observations of Young Star binaries 0.”1 to ~1” separations, Programs ongoing using NIFS, SINFONI & OSIRIS

Young Star Binaries – Z CMa

• OASIS observations in [OI] 6300A

Garcia et al. “Spatially resolved spectroscopy of Z Canis Majoris components” 1999, A&A v.346, 892

• Protostellar B star (Herbig Be star) primary, FU Ori eruptive variable companion

• System has become a prototype for understanding eruptive mass accretion in young star binaries

0.”1 binary observed with OASIS – 0.”11

microlenses!

Young Star Binaries – Z CMa

• Keck OSIRIS [Fe II] 1.644m observations of Z CmaWhelan et al. “The 2008 Outburst of Z CMa: The First Detection of Twin

Jets” 2010, ApJL v.720,L119

• The Massive Herbig Be star does drive the parsec scale outflow!•The companion is discovered for the first time to drive its own small scale jet

•First detection of a collimated jet from a FU Ori outbursting variable star!

High Contrast IFU Spectroscopy in Star Formation – Gas in Circumstellar Disks

HH 30

Dust in Circumstellar Disks – Traced by infrared excessEmission, seen in scattered light images of T Tauri starsGas in Circumstellar Disks – As much as 99% of the mass in circumstellar disks is in GAS not DUST

Disk Gas is traced by:• mm molecular observations of cold outer disk gas• IR emission species trace warm gas from ~terrestrial regions of disks

Most studies cannot spatially resolve the gas in the inner disk regions and measure trace components of the disks, ~70% of the disk by mass is in H2

The Search for IR Molecular Hydrogen Gas in Young Star Disks

FWHM ~0.”1

Beck et al. “Spatially Resolved Molecular Hydrogen in the Inner 200 AU Environments of T Tauri Stars” 2008 ApJ, v.676, 472

Gemini + NIFS IFU

observations of six T Tauri Stars – all

known to drive YSO outflows

K-band Continuum

Images


Herbig Haro Flows

From Classical T Tauri stars w/

outflows, H2 arises from

shocked emission

surrounding the HH flows

Beck et al. “Spatially Resolved Molecular Hydrogen in the Inner 200 AU Environments of T Tauri Stars” 2008 ApJ, v.676, 472

IFU Observations of T Tau Across a Decade…

Herbst et al. 1996MPE 3D Data from Calar Alto 3.5m

Jan. 1995

Beck et al. 2008NIFS Data from Gemini-N 8m

Oct. 2005

The Search for Molecular Hydrogen Gas in Young Star

Disks

• VLT + SINFONI Observations of T Tau, detection of H2 from the face-on disk around T Tau N?

Gustofsson et al. “Spatially resolved H2 emission from the disk around T Tau N”

2008

H2 EmissionFlux

H2 Velocity

H2 Velocity Dispersion

T Tau in [Fe II]

Where is the IR Molecular Hydrogen Gas in Young Star Disks?

• Doing a Gemini + NIFS IFU survey of additional young stars, more than doubling the past sample – this includes stars that have evidence for dust disk gaps (from IR SED shapes), and/or “disk-like” H2 from past long-slit observations

Highlight = GG Tau A, 0.”3 binary young star, with the prototypical “Circumbinary Ring” of dust (Roddier et al. 1996)

Subaru CIAO Observations of GG Tau A

*

Circumbinary Ring seen in scattered light

3”

T. Beck, J. Bary et al. “The Search for Spatially Resolved IR H2 from the Disks of

Classical T Tauri Stars” (in prep.)

The Search for IR H2 from a Disk High Contrast for Star Formation

NIFS 2.12m continuum image of the 0.”3 GG Tau A binary

IR Spectrum of GG Tau A – typical of young starsBr

H2??

Fe I

Looking for a signal of ~few 100 cts, on a continuum of 30K+ cts, with a photospheric Fe I feature in the way!

H2!!


T. Beck, J. Bary et al. “The Search for Spatially Resolved IR H2 from the Disks of Classical T Tauri Stars” (in prep.)



H2 Emission in the Environment of GG Tau A

• H2 2-1 S(1) / 1-0 S(1) line ratio not indicative of fluorescent pumping by UV photons, is consistent with X-ray heating of the gas• Gas/Dust in Protostellar binaries should NOT exist (Artymowicz & Lubow 1994):

• Circumstellar: at spatial locations beyond ~1/3 of the semi-major axis of the binary (disk truncation)• Circumbinary: at spatial locations within ~3x the semi-major axis of the binary (gap clearing)

• Clearing timescale ~100’s of years!

H2 1-0 S(1) @ 2.12m



H2 1-0 S(1) @ 2.12m

40AU – Pluto’s semi-major axis

H2 1-0 Q(1) @ 2.40m

Cutting Edge SF Science: Laser-Fed AO Observations of Young Stars

Perrin et al. “Laser Guide Star Adaptive Optics Integral Field Spectroscopy of a Tightly Collimated Bipolar Jet from the Herbig Ae star LkH 233” 2007 ApJ, v.670,

499

• Comparably few detailed spatially resolved observations of collimated outflows toward protostars with higher mass than the sun-like T Tauris.

• Keck Observatory LGS AO + OSIRIS IFU Observations of the very young Herbig Ae star LkH 233

• Investigate whether the similarity on large spatial scales between outflows from T Tauri and Herbig Ae stars still holds true on finer spatial scales.

Pushing to Higher Mass:

Cutting Edge SF Science: Laser-Fed AO Observations of Young Stars

Perrin et al. “Laser Guide Star Adaptive Optics Integral Field Spectroscopy of a Tightly Collimated Bipolar Jet from the Herbig Ae star LkH 233” 2007 ApJ, v.670,

499

Cutting Edge SF Science: Laser-Fed AO IFU Observations of Young Stars

• IRAS 04158+2805 = young proto-object in the Taurus SFR (d~140pc)

• Seen in the optical largely in scattered light, with a ‘bipolar’ nebula structure typical of opaque disk material along the mid-plane (Glauser et al. ’08), interpreted as a source with a disk inclined by ~63o

• YOUNG! (<~1Myo!) w./ M6 type, commonly adopted SpT for young BD limit

• HR Diagram fitting = substellar ~0.05Msolar (large uncertainty in models)

• Andrews et al ‘08 detected the disk in sub-mm, high spatial resolution dust continuum and CO gas! extends out to >~500AU from the central source - MASSIVE disk with ~1000+ AU total extent!

• Stellar mass estimate + extended massive disk! – Mdisk / Mstar ~15-20%!

HST Image From Glauser et al. 2008

Beck et al. “Laser Fed Adaptive Optics Imaging Spectroscopy of the CandidateProto-Brown Dwarf IRAS 04158+2805”

in Prep.

Pushing to Lower Mass:

Laser-fed AO Spectral Imaging, IRAS 04158+2805

– Gemini LGS AO w/ NIFS = Goal - Determine if H2 gas traces disk material in the BD candidate environment - it doesn’t!

– Data reveals fspatially resolved 2-D spectral images of a well collimated jet from a very young BD candidate

– BLUE-shifted, collimated [Fe II] jet associated with the brighter lobe of the scattered light nebulosity - no redshifted jet detected

– Jet Orientation consistent w/ 63o viewing disk inclination

1.644m [Fe II](Jet!)

2m K-band(Scattered Light!)

2.12m H2

(Wide-Angle Outflow!)

100

AU

Beck et al. “Laser Fed Adaptive Optics Imaging Spectroscopy of the CandidateProto-Brown Dwarf IRAS 04158+2805” in Prep.

Laser-Fed Spectral Imaging of BD Laser-Fed Spectral Imaging of BD EnvironmentsEnvironments

• Laser-Fed AO on large ground-based telescopes is a powerful means to reveal the inner environments of BDs at high spatial resolution using IR emission lines…

• Complication = BDs are optically very faint, but you need an optical tip-tilt guide star! (TTGS)

• Observations of IRAS 04158+2805 were only possible with Gemini +LGS AO because of the nearby r~17.6 magnitude guide star

AO TTGS Area

TTGS r~17.6mag IRAS 04158+2805

K~11.6 mag, R~21

Gemini Observing Tool View

The Future: SF Science with the JWST and ELT IFUs

FAINTER!FAINTER!More Distant– Probe the Star

formation process to low mass M

stars, approaching the BD limit in the

LMC and SMC!

More Distant– Probe the Star

formation process to low mass M

stars, approaching the BD limit in the

LMC and SMC!

Higher Mass – Massive O&B stars form in very dense

cocoons of gas+dust, pierce

through the extinction to see

the forming stars!

Higher Mass – Massive O&B stars form in very dense

cocoons of gas+dust, pierce

through the extinction to see

the forming stars!

Lower Mass – BDs and Free-Floating Planets in nearby

star forming regions like Taurus

and Orion!

Lower Mass – BDs and Free-Floating Planets in nearby

star forming regions like Taurus

and Orion!

Younger – Sun-Like stars at earlier

epochs of formation – the

“Class I” phase w/ envelope material remaining, or even

younger!

Younger – Sun-Like stars at earlier

epochs of formation – the

“Class I” phase w/ envelope material remaining, or even

younger!

Spectral Imaging of young Star Spectral Imaging of young Star Environments with Environments with JWSTJWST

• The James Webb Space Telescope - operating at L2 in ~2014

• 6.5m Segmented Primary• 4 Science Instruments:

– NIRCam - Near-InfraRed Camera

– NIRSpec - Near-InfraRed Spectrograph w/ IFU!

– TFI - Tunable Filter Imager– MIRI - Mid-InfraRed

Instrument w/ IFU

The James Webb Space Telescope

NIRSpec and MIRI have Integral Field Units for very sensitive high-contrast spectral imaging of young star environments.

A schematic view of the JWST focal plane, including the placement of the science

entrance apertures for each instrument.

The Future: SF Science with IFUs on the ELTs

GMT

TMT

Nearby T Tauri stars are bright for large aperture telescopes – but we really need the ELT spatial resolution

to push our observations to the ~Jupiter environs!

When considering properties for IFUs for large telescopes, please don’t forget about star formation science! & Consider

a high spectral resolution IFU mode for the IR…!!

For Kinematics and spectral line detection/characterization, star formation science

greatly benefits from HIGH spectral resolution! (R~20,000 or greater)

Mandell et al. (2009) R~27,000

The Future: Next Generation Observations of T Tau?

Herbst et al. 1996Data from Jan.

1995 Beck et al. 2008Data from Oct. 2005

?THANKS!! For Your Attention!

Next GenerationIFU View of T Tau

Documents

Galactic Star Formation Science