GMT2010: High-resolution Spectroscopy ofStars with GMTNIRS

GMT2010Seoul, Korea

David L. LambertMcDonald ObservatoryThe University of Texas at Austin

William Herschel (1738-1822)William Herschel (1738-1822) Discovered the infra-red in 1800Discovered the infra-red in 1800 “ “By placing one thermometer within By placing one thermometer within

the [solar] red rays, separated by a the [solar] red rays, separated by a prism, and another beyond them, he prism, and another beyond them, he found the temperature of the found the temperature of the outside thermometer raised by outside thermometer raised by more than that of the inside.” more than that of the inside.”

Humphrey Davy to Davies GiddyHumphrey Davy to Davies Giddy 3 July 18003 July 1800

IntroductionIntroductionCertain exciting problems in stellar astrophysics Certain exciting problems in stellar astrophysics

demanddemandhigh-resolution IR spectra for their solution.high-resolution IR spectra for their solution.

IR advantages include:IR advantages include: Cool starsCool stars

- bright in IR- bright in IR - IR spectra “simpler” than optical- IR spectra “simpler” than optical - key signatures in IR: molecules for elemental- key signatures in IR: molecules for elemental

and isotopic abundancesand isotopic abundances - H- H- - opacity minimum at 1.6 µmopacity minimum at 1.6 µm

- higher dust transparency- higher dust transparency Cool gas and dustCool gas and dust

- circumstellar envelopes- circumstellar envelopes - prestellar disks- prestellar disks

GMTNIRS: J, H, K, L, M (1.15-5.0GMTNIRS: J, H, K, L, M (1.15-5.0m) in a single exposurem) in a single exposure

IntroductionIntroductionSpectra must be paired with Spectra must be paired with

model model atmospheres and atmospheres and

atomic/molecularatomic/moleculardatadata Atomic spectroscopy: generally high-Atomic spectroscopy: generally high-

excitation excitation neutral atomic linesneutral atomic lines

- Quantitative lab spectroscopy limited - Quantitative lab spectroscopy limited (gf-values for LTE)(gf-values for LTE) - Expect theoretical gf-values to be fairly - Expect theoretical gf-values to be fairly reliablereliable - Astrophysical data (e.g., gf’s from Sun, - Astrophysical data (e.g., gf’s from Sun, Arcturus, etc.)Arcturus, etc.) Few resonance and low excitation lines.Few resonance and low excitation lines. Therefore - clean spectrum at low metallicity Therefore - clean spectrum at low metallicity

Molecular spectroscopyMolecular spectroscopy Mix of electronic and vibration-rotation transitionsMix of electronic and vibration-rotation transitions Molecular data generally good but incomplete, but there are few Molecular data generally good but incomplete, but there are few

active centers for lab/theoretical work on astrophysical moleculesactive centers for lab/theoretical work on astrophysical molecules Incomplete: stellar column densities Incomplete: stellar column densities »» laboratory possibilities laboratory possibilities

(beware of extrapolation)(beware of extrapolation) : dissociation energies?: dissociation energies?

: gf-values?: gf-values? : new molecules (ZrS, TiS) : new molecules (ZrS, TiS) Can usually predict isotopic wavelength shiftsCan usually predict isotopic wavelength shifts C, N, O and F including isotopes accessible (in principle)C, N, O and F including isotopes accessible (in principle)

chemical evolution of stellar systemschemical evolution of stellar systems stellar evolution, esp. dredge-upsstellar evolution, esp. dredge-ups

IntroductionIntroduction

GMTNIRS performance:GMTNIRS performance: Single exposure: J, H, K, L and M (1.15-5.0Single exposure: J, H, K, L and M (1.15-5.0m) m) at R = at R = λλ/∆ /∆ λλ = 50,000 (JHK) or 100,000 (LM) = 50,000 (JHK) or 100,000 (LM) SlitSlit 0.085 x 1.3 arc sec with pixel scale of 20 mas0.085 x 1.3 arc sec with pixel scale of 20 mas Limiting magnitudeLimiting magnitude

Special (unique) factors: All in one Special (unique) factors: All in one exposureexposure CNO as tracers of dredge-ups in starsCNO as tracers of dredge-ups in stars

CO CO = 1 in M, = 1 in M, = 2 in K, = 2 in K, = 3 in H = 3 in HCN Red system in JHKCN Red system in JHKOH OH = 1 in L, = 1 in L, = 2 in H = 2 in HNH NH = 1 in L = 1 in L

CC22 Ballik-Ramsay and Phillips in HK Ballik-Ramsay and Phillips in HK (also HF in K and HCl in L)(also HF in K and HCl in L)

Obtain CNO elemental and isotopic abundancesObtain CNO elemental and isotopic abundances Probe atmospheric dynamics and structure (MOLSPHERE)Probe atmospheric dynamics and structure (MOLSPHERE)

Special (unique) factors: All in one Special (unique) factors: All in one exposureexposure HR4049, a very metal-poor 7500K giant HR4049, a very metal-poor 7500K giant in a binary with a circumbinary disk:in a binary with a circumbinary disk: [Fe/H] = -4.7, but [C, N, O / H] [Fe/H] = -4.7, but [C, N, O / H] 0.0 0.0

Cold CO in absorption at 2.3µmCold CO in absorption at 2.3µm

Lambert, Hinkle & Luck (1988)

Special (unique) factors: All in one Special (unique) factors: All in one exposureexposure(HR 4049 – continued)(HR 4049 – continued) Look for CO at 4.6µm to obtain Look for CO at 4.6µm to obtain 1212C/C/1313C and C and 1616O/O/1717O ratiosO ratios

Hinkle, Brittain & Lambert (2007)

C18O18COCO

H2OC17O

Special (unique) features: Angular Special (unique) features: Angular resolutionresolution(aperture, AO, pixel scale)(aperture, AO, pixel scale) Mass loss by red giant (or all) stars is very poorly understood Mass loss by red giant (or all) stars is very poorly understood

theoreticallytheoretically and observationally.and observationally.

Map circumstellar structure in CO 4.6µm linesMap circumstellar structure in CO 4.6µm lines

Smith et al. (2009)

Special (unique) features: Angular Special (unique) features: Angular resolutionresolution(aperture, AO, pixel scale)(aperture, AO, pixel scale)

HST/WFPC 2 Phoenix slit positions

Smith et al. (2009, AJ, 137, 3558)

Special (unique) features: Angular Special (unique) features: Angular resolutionresolution(aperture, AO, pixel scale)(aperture, AO, pixel scale)

Smith et al. (2009)

Special (unique) features: Angular Special (unique) features: Angular resolutionresolution(aperture, AO, pixel scale)(aperture, AO, pixel scale) Velocity-position mapsBetelgeuse VY CMaKI 7699 Å CO 1 – 0 R2 4.64μm

Slit 4'' from star x: 1 pixel = 1.3 km/s y: 1 pixel = 0''.27

Slit 33'' from star Plez & Lambert (2002)

Smith et al. (2009)

Special (unique) features: Angular Special (unique) features: Angular resolutionresolution(aperture, AO, pixel scale)(aperture, AO, pixel scale) Betelgeuse and VY CMa are SN II progenitorsBetelgeuse and VY CMa are SN II progenitors Maps of circumstellar envelopesMaps of circumstellar envelopes

clues to mass loss understandingclues to mass loss understanding environment in which SN II explodesenvironment in which SN II explodes

CO has advantages over KI or NaICO has advantages over KI or NaI GMTNIRS with JHKLM coverage will reveal completeGMTNIRS with JHKLM coverage will reveal complete circumstellar coverage (despite short slit)circumstellar coverage (despite short slit)

- will provide look at innermost regions- will provide look at innermost regions - larger number of giants in its grasp- larger number of giants in its grasp

Special (unique) features: Limiting Special (unique) features: Limiting magnitudemagnitude LMC, SMC, and just a little furtherLMC, SMC, and just a little further

Dredge-up in red giantsDredge-up in red giants

Special (unique) features: Limiting Special (unique) features: Limiting magnitudemagnitudeOrigins of Origins of FluorineFluorine FCNO and internal FCNO and internal

mixingmixing

Smith et al. (2005) Smith et al. (2002)

Special (unique) features: Limiting Special (unique) features: Limiting magnitudemagnitude

K- 12.5

- 15.5

- 15.5

Smith et al. (2002)

Special (unique) features: Limiting Special (unique) features: Limiting magnitudemagnitude Dwarf galaxies beyond the LMC at distance modulus of 18.5Dwarf galaxies beyond the LMC at distance modulus of 18.5

Sculptor 19.5Sculptor 19.5 Sextans 19.7Sextans 19.7 Carina 20.0Carina 20.0 Fornax 20.7Fornax 20.7

Large surveys of “nearby” systems and starsLarge surveys of “nearby” systems and stars - Our globular clusters- Our globular clusters - Field stars after GAIA- Field stars after GAIA

CNOF chemical evolution and internal mixingCNOF chemical evolution and internal mixing

DO NOT FORGET!DO NOT FORGET! Glorious puzzles remain in stellar astrophysics in this age of Glorious puzzles remain in stellar astrophysics in this age of

cosmologycosmology

The GMT and GMTNIRS will help solve many puzzlesThe GMT and GMTNIRS will help solve many puzzles

“ “Nature shows us of the lion Nature shows us of the lion only the tail. But there is no only the tail. But there is no doubt in my mind that the doubt in my mind that the lion belongs with it, even if he lion belongs with it, even if he cannot reveal himself to the cannot reveal himself to the eye all at once because of his eye all at once because of his huge dimensions.”huge dimensions.”

A. EinsteinA. Einstein

Even Einstein observed!Even Einstein observed!

The GMT will reveal the lions!