GMTNIRS Science - Centre for Astrophysics and · PDF fileBean et al. (2010 ApJ 713 410; 2010...

1

David Yong (ANU)

GMTNIRS Science

GMTNIRS Science: D Yong 2

Why IR? Why high resolution?

•Molecular lines from a variety of astrophysical sources (stellar, circumstellar, protostellar, interstellar, planetary, protoplanetary ...) are unique to the near IR (1-5 microns)

•High spectral resolution (R=100,000; 3 km/s) resolves most lines permitting detailed studies of line profiles (chemical abundances, rotational and radial velocities, magnetic fields, isotopic ratios ...)



Phoenix@Gemini-S 2010A

• The Dancing Partners of Seven Dwarfs• Chemical Abundances in Giant Stars of Newly Discovered Infrared

Globular Clusters• Radial Velocity of Low-mass Candidates Members of Nearby Young

Associations• Unveiling the central kinematics of Centaurus A• Origin and formation of circumstellar disks around B[e] supergiants• Multiple Stellar Populations in the Globular Cluster M22: a study of

C+N+O abundances• Pluto's Atmospheric CH4: Variations in time, space, and altitude



• Fluorine abundances in thin and thick disk stars• Chemical abundances of C, N, and F in M4 giant stars: The origin of

the multipopulations in Globular Clusters• Using H3+ Observations to Estimate the Interstellar H2

Temperature• Testing the Binary Hypothesis for Bipolar Proto-Planetery Nebulae• High resolution near-IR spectroscopic characterization of post-

common envelope low mass companions among nearby WDs• Testing for the existence of massive Population III stars with stellar

archaeology• Carbon Chain Circumstellar Chemistry in Carbon Stars

Phoenix@Gemini-S 2010A



CRIRES@VLT Period 85

• The distribution of Io's atmosphere from 4 mum spectroscopy• Individual dynamical mass determination of the binary brown dwarf

KELU-1,AB - , 8th epoch• Confirming the existence of a giant planet orbiting HD,192263• Protoplanetary disk rotation probed via spectroastrometry• The metallicity, mass-loss rates and dust-to-gas ratios of carbon

stars in the Galactic halo• Comprehensive study of M-dwarfs magnetic fields through atomic

and molecular lines with CRIRES• Addressing the O Star Weak-wind Problem Using Br-alpha• The isotopic and molecular composition of the first Herschel ToO

comet



• Measuring the magnetic fields of pre-main sequence stars• Using fluorine to probe intriguing differences in the chemical

enrichment history of field and cluster stars• Tracing the formation of the Galactic bulge from CNO abundance

trends in the Sagittarius window• Simultaneity of Accretion and Outflow in Young Stars• First Glimpse at Giant Planets Being Born: Multiepoch CRIRES

Observation of Two Transitional Protoplanetary Disks• A Deep Search for Biological Signatures on Mars critically

supporting the Herschel mission• A High Precision Radial Velocity Search for Planets Around the

Lowest Mass Stars




• Measuring the magnetic fields of pre-main sequence stars• Using fluorine to probe intriguing differences in the chemical

enrichment history of field and cluster stars• Tracing the formation of the Galactic bulge from CNO abundance

trends in the Sagittarius window• Simultaneity of Accretion and Outflow in Young Stars• First Glimpse at Giant Planets Being Born: Multiepoch CRIRES

Observation of Two Transitional Protoplanetary Disks• A Deep Search for Biological Signatures on Mars critically

supporting the Herschel mission• A High Precision Radial Velocity Search for Planets Around the

Lowest Mass Stars


GMTNIRS WILL DO ALL THIS AND MORE!

+ ALL THE PROJECTS BEING DONE WITH

KECK + NIRSPEC (R<25,000)SUBARU + IRCS (R<20,000)IRTF + CSHELL (R<30,000)



GMTNIRS: An unfair advantage

• 3-4 magnitudes deeper than CRIRES@VLT and 20 times more instantaneous wavelength coverage• 4-5 magnitudes deeper than PHOENIX@Gemini-S and 40 times more instantaneous wavelength coverage

• This represents a significantly larger improvement than achieved in optical high-resolution spectroscopy going from 4m telescopes to the Keck. • It is also a larger gain than for any other instrument contemplated for GMT


GMTNIRS Science: D Yong 8 Science Case

Slide from Dan Jaffe (UT)

Science Case: Protostars IGRINS and GMTNIRS will bring the study of young, obscured objects to the same level of precision as we have for MS and PMS stars.

(Courtesy of K. Covey)

We can use the broad instantaneous spectral coverage to produce quantitative information about protostars, including magnetic field strength (Zeeman splitting), accretion rates (Brackett line profiles), cluster kinematics (radial velocities), and fundamental stellar parameters (Teff, log g, abundances).


Science Case: Protoplanetary DisksWe can determine gas chemistry and excitation as a function of radius and age.Spectroscopic techniques can be as valuable as imaging techniques in unveiling the details of the excitation and abundance distributions in disks

Water and CO lines in V1331 Cyg (Najita et al. 2009). The vertical lines show the positions of water features. MWC 480 for comparison.

Chemical evolution clearly plays a role in the formation of planets and other bodies, and in the issue of habitability. In analogy to what Prof. Lee and her collaborators are doing for the collapse phase, IR spectroscopy is the ideal tool for studying the chemical evolution of the planet forming regions of disks.




Science Highlights: Low mass stars in superstar clustersHow are the objects grouped kinematically? Are there local abundance variations? Are tight binaries common initially?

Core of NGC 3603Harayama et al. 2008

Massive clusters in our Galaxy are the closest analog to starbursts



Black holes in Galactic Center and Nearby Galaxies

With GMTNIRS, we can follow stars as they sweep past the 4 million solar mass black hole in the galactic center, measuring radial velocity and examining the effects of tidal distortion on the stellar atmospheres. Nowhere else in the universe can we study the interaction of black holes and the stellar nuclei of galaxies in such detail. In other nearby galaxies, we can use correlation techniques to find the highest velocity (closest orbits) by separating the sources in the spectral direction to beat confusion.

Paths of late-type stars orbiting the black hole in the Galactic Center. Closest approaches are <0.04 pc


Planets

Stellar Chemical Compositions

Information kindly provided by Jacob Bean (CfA)

• With CRIRES@VLT, Jacob Bean et al. are conducting a Large Progamme “A search for planets around the lowest mass stars”

• R=100,000, S/N=200, ammonia gas cell (which provides calibration lines near 2.3 microns), + stellar CO lines

• Obtained long-term (1+ year) velocity precision of 5 m/s: => 5 Mearth at P = 10d and 15 Mearth at P = 1yr around M = 0.15 MSun

• Limiting factors are (modelling) telluric lines and in the absence of an ultra-stable spectrograph, large wavelength coverage is only useful if combined with an appropriate gas cell

Bean et al. (2010 ApJ 713 410; 2010 ApJ 711 L19)

GMTNIRS Science: D Yong

Stellar Chemical Compositions with GMTNIRS

13

GMTNIRS & Stellar Alchemy

The Chemical Enrichmentof the

Milky Way GalaxyRingberg Castle, Germany - May 10-14, 2010



Two questions, one solution

Q1: FORMATION AND EVOLUTION OF GALAXIES

Q2: ORIGIN AND EVOLUTION OF THE CHEMICAL ELEMENTS

A: MEASURE ELEMENTAL AND ISOTOPIC ABUNDANCES,IN ALL STELLAR POPULATIONS,

AND COMPARE THESE DATA TO PREDICTIONS



• Gas is first enriched by the products of the shortest lived stars

• Massive stars produce and eject the so-called !-elements (O, Mg, Si, S, Ca and Ti[?]) and r(apid) neutron-capture process elements (Eu)

15

Chemical evolution

WHEN STAR FORMATION COMMENCES ...





15

Chemical evolution


Melendez et al. (2008)





• A little later (~108 years), intermediate-mass stars contribute ejecta from asymptotic giant branch (AGB) stars, and the s(low) neutron-capture process elements (Sr, Ba, La) begin to appear

15

Chemical evolution







15

Chemical evolution


Simmerer et al. (2004)






• Only later (~109 years) do the Fe-peak elements arise in greater abundances as Type Ia supernovae enrich the interstellar medium

15

Chemical evolution




Chemical evolution

KEY PROCESSES INVOLVED INCLUDE

• Star formation rate: how metal-rich does the [!/Fe] ratio extend, or where does the “knee” in [!/Fe] appear

• Initial mass function: what is the level of [!/Fe]

• Infall and mixing: what is the scatter in [X/Fe] at a given metallicity

• Degree and extent of recycling of the products of stellar nucleosynthesis

• Yields of many elements depend on mass and metallicity, so [X/Fe] ratios probe the star formation and chemical enrichment history



Two questions, one solution

Q1: FORMATION AND EVOLUTION OF GALAXIES

Q2: ORIGIN AND EVOLUTION OF THE CHEMICAL ELEMENTS


A: MEASURE ELEMENTAL AND ISOTOPIC ABUNDANCES,IN ALL STELLAR POPULATIONS,

AND COMPARE THESE DATA TO PREDICTIONS

Red Giants


Advantages of the infrared

1. FLUX DISTRIBUTION OF COOL STARS FAVOURS THE IR

IR Advantages



2. CONTINUUM IDENTIFICATION (LINE DENSITY)

IR Advantages

Coelho et al. (2005)



For cool stars,the optical regionis very crowded.

The IR is much cleaner

Identifying the continuum is critical for

reliable chemicalabundances


SameStar

IR Advantages




For cool stars,the optical regionis very crowded.

The IR is much cleaner

Identifying the continuum is critical for

reliable chemicalabundances


Line strength depends on the ratio of line opacity to continuous opacity

SameStar

IR Advantages



Note minimumin total

continuousopacity @1.6

microns

21


3. MINIMUM IN CONTINUOUS OPACITY (CLOSE TO LTE)

David Gray (1992)

Continuumforms deepest,i.e., closer to

LTE

Teff=6428K

IR Advantages



Novotny (1973)

Teff=3880K




microns


LTE

IR Advantages



Novotny (1973)

Teff=3880K




microns


LTE

LTE = Local Thermodynamic Equilibrium

When LTE is valid, the analysis is greatly simplified

IR Advantages



4. ISOTOPES (CARBON)

Smith et al. (2002)

12C/13C

Isotopic shifts are larger for molecules compared to atoms

IR Advantages



Smith et al. (2002)

4. ISOTOPES (CARBON)

IR Advantages



Clayton et al. (2007)

18O 16O

4. ISOTOPES (OXYGEN)

IR Advantages



Harris et al. (1988)

4. ISOTOPES (OXYGEN)

IR Advantages



Tsuji et al. (1994)

29Si

28Si

4. ISOTOPES (SILICON)

IR Advantages



Tsuji et al. (1994)

30Si

28Si29Si

4. ISOTOPES (SILICON)

IR Advantages



5. REDDENING

E(B-V) = (B-V) - (B-V)0

AV = V - V0 = 3.12 ! E(B-V)

AK = K - K0 = 0.34 ! E(B-V)

AV/AK ~ 9

IR Advantages


Example of IR spectra

Ryde et al. (2010)

IR Advantages


Disadvantages of the infrared

1. ABSENCE (OR LACK) OF HEAVY ELEMENTS

Few, if any, lines from heavy elements such as the s-process (produced in AGB stars) and the

r-process (produced in massive stars).

Efforts are underway to find such lines in the IR, large increase in wavelength coverage is helpful.

IR Disadvantages


Other concerns

2. LACK OF COVERAGE BETWEEN 900NM AND 1.2MICRONS

The proposed high resolution spectrographs will not cover the region between 950(?) nm and 1.15(?)

microns.

In this region are atomic lines of the biogenic elements (Sulfur -- not depleted on dust -- and Phosphorus)

as well as molecular lines of FeH (from which Fe isotope ratios may be extracted)

and He 10830Å

IR Disadvantages


The competition(?)

3. APOGEE

Credit: Jennifer Johnson (OSU)

!!SDSS-III survey !!High-resolution H-band survey (15

elements) !!R~28,000, spectra on 3 chips, 300 fibers !!105 Galactic stars (mostly red giants) !!H < 12.5 (usually) !!S/N~100 per res. element !!May 2011-June 2014 !!Observations in highly reddened

regions !!All Galactic populations: disk, halo &

bulge

Apache Point Observatory Galactic Evolution Experiment

IR Disadvantages


Resolution is important!

Hinkle et al. (1995)

FTS

GMTNIRS

APOGEE

IR Disadvantages

Arcturus


3. APOGEE

Credit: Jennifer Johnson (OSU)

The competition(?)

IR Disadvantages


Old(?) Specs and TargetsJaffe

(circa Jan 2009)

Ryde (2010)

Science

Out of date(!) values

David Yong

David Yong

David Yong

David Yong

David Yong


Mixing and nucleosynthesis

Lederer et al. (2009)

DREDGE-UP IN LMC AGB STARS

Science


Chemical evolution of the bulge

INHOMOGENEOUS SAMPLE (DWARFS & GIANTS)

Zoccali et al. (2006)

Bulge giants

Thin disk dwarfs

Thick disk dwarfs

Science


Chemical evolution of the bulge


DIFFERENTIAL HOMOGENEOUS ANALYSIS OF GIANTS

Bulge

Thick disk

Thin disk

Halo

Science


Two distinct halo populations

Nissen & Schuster (2010)

MORE DIFFERENTIAL (OPTICAL) ANALYSES

5200 < Teff < 6300 Vtotal > 180 km/s[Fe/H] > -1.6

Science


Summary

GMTNIRS PROVIDES HIGH SPECTRAL RESOLUTION, LARGE WAVELENGTH COVERAGE, NEAR-IR SPECTRA

THIS WILL ENABLE STUDIES OF

Star formation Planet formation

Radial velocities Circumstellar disks

Planetary atmospheres Chemical abundances

Magnetic fields Mass-loss

+++ ...

Summary


Summary: chemical abundances

• ULTIMATELY, A DEFINITIVE STAR FORMATION AND CHEMICAL ENRICHMENT HISTORY OF THE DIFFERENT GALACTIC POPULATIONS IS LACKING.

• WHAT IS NEEDED IS TO STUDY DETAILED CHEMICAL ABUNDANCE RATIOS IN LARGE NUMBERS OF STARS IN ALL GALACTIC POPULATIONS AND IN LOCAL GROUP GALAXIES

• HIGH RESOLUTION IR SPECTROSCOPY OF RED GIANTS PRESENTS THE BEST OPPORTUNITY

• RED GIANTS ARE BRIGHT AND PROBE REGIONS NOT ACCESSIBLE BY F/G/K DWARFS (E.G., BULGE, EXTERNAL GALAXIES)

Summary


RED GIANTS FLUX DISTRIBUTION FAVOURS THE IR

LINE DENSITY OF RED GIANTS FAVOURS THE IR

IR RADIATION PENETRATES THROUGH GAS AND DUST

AO SYSTEMS ARE OPTIMAL IN THE IR, BETTER SPATIAL RESOLUTION FOR

CROWDING AND S/N CONSIDERATIONS

Summary: red giants + IR

Summary


Summary: analysis issues

MINIMUM IN H- CONTINUOUS OPACITY MEANS THE LINES FORM DEEPER AND CLOSER TO LTE

MANY DIATOMIC MOLECULES IN THE IR ARE “PURE” VIBRATION-ROTATION TRANSITIONS FOR WHICH LTE IS VALID

Summary


Summary: requirements

SPATIAL RESOLUTION (GMT-APERTURE)

SPECTRAL RESOLUTION (R=100,000)

WAVELENGTH COVERAGE (THE LARGER THE BETTER)

MULTIPLEXING HIGHLY DESIRED (!!!)

Summary

• Jaffe et al. (2006 SPIE 6269 E 143)

• Allende Prieto et al. (2008, Astronomische Nachrichten, 329, 1018)

• Ryde (2010, Astronomische Nachrichten, 331, 433)

• GMT Science Case http://www.gmto.org/sciencecase

• Talks by David Lambert and Peter McGregor at the Science with The Giant Magellan Telescope Canberra, Australia March 26-28, 2008

• CRIRES overview http://www.eso.org/sci/facilities/paranal/instruments/crires/overview.html

References

End

http://www.eso.org/sci/facilities/paranal/instruments/crires/overview.html

http://www.eso.org/sci/facilities/paranal/instruments/crires/overview.html

http://www.gmto.org/sciencecase

http://www.gmto.org/sciencecase

GMTNIRS Science - Centre for Astrophysics and · PDF fileBean et al. (2010 ApJ 713 410; 2010...

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Transcript of GMTNIRS Science - Centre for Astrophysics and · PDF fileBean et al. (2010 ApJ 713 410; 2010...