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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 ...)
Why IR? Why high resolution?
GMTNIRS Science: D Yong 3
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
Why IR? Why high resolution?
GMTNIRS Science: D Yong 4
• 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
Why IR? Why high resolution?
GMTNIRS Science: D Yong 5
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
Why IR? Why high resolution?
GMTNIRS Science: D Yong 6
• 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
CRIRES@VLT Period 85
Why IR? Why high resolution?
GMTNIRS Science: D Yong 6
• 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
CRIRES@VLT Period 85
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)
Why IR? Why high resolution?
GMTNIRS Science: D Yong 7
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
Why IR? Why high resolution?
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).
GMTNIRS Science: D Yong 9 Science Case
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.
Slide from Dan Jaffe (UT)
GMTNIRS Science: D Yong 10 Science Case
Slide from Dan Jaffe (UT)
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
GMTNIRS Science: D Yong 11 Science Case
Slide from Dan Jaffe (UT)
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
GMTNIRS Science: D Yong 12
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
Stellar Chemical Compositions
GMTNIRS Science: D Yong 14
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
Stellar Chemical Compositions
GMTNIRS Science: D Yong
• 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 ...
Stellar Chemical Compositions
GMTNIRS Science: D Yong
• 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 ...
Melendez et al. (2008)
Stellar Chemical Compositions
GMTNIRS Science: D Yong
• 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)
• 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
WHEN STAR FORMATION COMMENCES ...
Stellar Chemical Compositions
GMTNIRS Science: D Yong
• 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)
• 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
WHEN STAR FORMATION COMMENCES ...
Simmerer et al. (2004)
Stellar Chemical Compositions
GMTNIRS Science: D Yong
• 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)
• 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
• Only later (~109 years) do the Fe-peak elements arise in greater abundances as Type Ia supernovae enrich the interstellar medium
15
Chemical evolution
WHEN STAR FORMATION COMMENCES ...
Stellar Chemical Compositions
GMTNIRS Science: D Yong
• 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)
• 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
• Only later (~109 years) do the Fe-peak elements arise in greater abundances as Type Ia supernovae enrich the interstellar medium
15
Chemical evolution
WHEN STAR FORMATION COMMENCES ...
Melendez et al. (2008)
Stellar Chemical Compositions
GMTNIRS Science: D Yong 16
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
Stellar Chemical Compositions
GMTNIRS Science: D Yong 17
Two questions, one solution
Q1: FORMATION AND EVOLUTION OF GALAXIES
Q2: ORIGIN AND EVOLUTION OF THE CHEMICAL ELEMENTS
Stellar Chemical Compositions
A: MEASURE ELEMENTAL AND ISOTOPIC ABUNDANCES,IN ALL STELLAR POPULATIONS,
AND COMPARE THESE DATA TO PREDICTIONS
Red Giants
GMTNIRS Science: D Yong 18
Advantages of the infrared
1. FLUX DISTRIBUTION OF COOL STARS FAVOURS THE IR
IR Advantages
GMTNIRS Science: D Yong 19
Advantages of the infrared
2. CONTINUUM IDENTIFICATION (LINE DENSITY)
IR Advantages
Coelho et al. (2005)
GMTNIRS Science: D Yong 20
Advantages of the infrared
For cool stars,the optical regionis very crowded.
The IR is much cleaner
Identifying the continuum is critical for
reliable chemicalabundances
2. CONTINUUM IDENTIFICATION (LINE DENSITY)
SameStar
IR Advantages
Coelho et al. (2005)
GMTNIRS Science: D Yong 20
Advantages of the infrared
For cool stars,the optical regionis very crowded.
The IR is much cleaner
Identifying the continuum is critical for
reliable chemicalabundances
2. CONTINUUM IDENTIFICATION (LINE DENSITY)
Line strength depends on the ratio of line opacity to continuous opacity
SameStar
IR Advantages
Coelho et al. (2005)
GMTNIRS Science: D Yong
Note minimumin total
continuousopacity @1.6
microns
21
Advantages of the infrared
3. MINIMUM IN CONTINUOUS OPACITY (CLOSE TO LTE)
David Gray (1992)
Continuumforms deepest,i.e., closer to
LTE
Teff=6428K
IR Advantages
GMTNIRS Science: D Yong 22
Advantages of the infrared
Novotny (1973)
Teff=3880K
3. MINIMUM IN CONTINUOUS OPACITY (CLOSE TO LTE)
Note minimumin total
continuousopacity @1.6
microns
Continuumforms deepest,i.e., closer to
LTE
IR Advantages
GMTNIRS Science: D Yong 22
Advantages of the infrared
Novotny (1973)
Teff=3880K
3. MINIMUM IN CONTINUOUS OPACITY (CLOSE TO LTE)
Note minimumin total
continuousopacity @1.6
microns
Continuumforms deepest,i.e., closer to
LTE
LTE = Local Thermodynamic Equilibrium
When LTE is valid, the analysis is greatly simplified
IR Advantages
GMTNIRS Science: D Yong 23
Advantages of the infrared
4. ISOTOPES (CARBON)
Smith et al. (2002)
12C/13C
Isotopic shifts are larger for molecules compared to atoms
IR Advantages
GMTNIRS Science: D Yong 24
Advantages of the infrared
Smith et al. (2002)
4. ISOTOPES (CARBON)
IR Advantages
GMTNIRS Science: D Yong 25
Advantages of the infrared
Clayton et al. (2007)
18O 16O
4. ISOTOPES (OXYGEN)
IR Advantages
GMTNIRS Science: D Yong 26
Advantages of the infrared
Harris et al. (1988)
4. ISOTOPES (OXYGEN)
IR Advantages
GMTNIRS Science: D Yong 27
Advantages of the infrared
Tsuji et al. (1994)
29Si
28Si
4. ISOTOPES (SILICON)
IR Advantages
GMTNIRS Science: D Yong 28
Advantages of the infrared
Tsuji et al. (1994)
30Si
28Si29Si
4. ISOTOPES (SILICON)
IR Advantages
GMTNIRS Science: D Yong 29
Advantages of the infrared
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
GMTNIRS Science: D Yong 30
Example of IR spectra
Ryde et al. (2010)
IR Advantages
GMTNIRS Science: D Yong 31
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
GMTNIRS Science: D Yong 32
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
GMTNIRS Science: D Yong 33
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
GMTNIRS Science: D Yong 34
Resolution is important!
Hinkle et al. (1995)
FTS
GMTNIRS
APOGEE
IR Disadvantages
Arcturus
GMTNIRS Science: D Yong 35
3. APOGEE
Credit: Jennifer Johnson (OSU)
The competition(?)
IR Disadvantages
GMTNIRS Science: D Yong 36
Old(?) Specs and TargetsJaffe
(circa Jan 2009)
Ryde (2010)
Science
Out of date(!) values
GMTNIRS Science: D Yong 37
Mixing and nucleosynthesis
Lederer et al. (2009)
DREDGE-UP IN LMC AGB STARS
Science
GMTNIRS Science: D Yong 38
Chemical evolution of the bulge
INHOMOGENEOUS SAMPLE (DWARFS & GIANTS)
Zoccali et al. (2006)
Bulge giants
Thin disk dwarfs
Thick disk dwarfs
Science
GMTNIRS Science: D Yong 39
Chemical evolution of the bulge
Melendez et al. (2008)
DIFFERENTIAL HOMOGENEOUS ANALYSIS OF GIANTS
Bulge
Thick disk
Thin disk
Halo
Science
GMTNIRS Science: D Yong 40
Two distinct halo populations
Nissen & Schuster (2010)
MORE DIFFERENTIAL (OPTICAL) ANALYSES
5200 < Teff < 6300 Vtotal > 180 km/s[Fe/H] > -1.6
Science
GMTNIRS Science: D Yong 41
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
GMTNIRS Science: D Yong 42
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
GMTNIRS Science: D Yong 43
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
GMTNIRS Science: D Yong 44
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
GMTNIRS Science: D Yong 45
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
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