ASTRONOMICAL APPLICATIONS OF NEW LINE LISTS FOR CN, C 2 AND THEIR ISOTOPOLOGUES P. F. Bernath Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA C. Sneden Department of Astronomy, The University of Texas at Austin, Austin, Texas J. S. A. Brooke and R.S. Ram Department of Chemistry, University of York, Heslington, York, UK

Interstellar CN Violet 0-0 B 2 Σ + -X 2 Σ + Diffuse interstellar cloud absorption towards the star HD Gredel et al. AA, 251, 625 (1991) Linelist is needed to get temperature and abundance (column density). T rot = 3 K (same temperature as the cosmic background radiation) [CN]/[ 13 CN]=38

Astronomical Requirements  From Beer-Lambert law: Need a lineshape function g( ν-ν 10 ) (assumed to be Voigt, etc.) and a line strength S ’ given by (SI units at temperature T, from Bernath, Spectra of Atoms and Molecules):  Therefore need a line position, ν 10, partition function, Q T (calculated), line intensity, S J′J″ (or S′), and the lower state energy, E low.  Linelist consists of (at a minimum): ν 10, S′ or A 10 and E low for each line

Selected New Astronomical Linelists 1. MgH B' 2 Σ + -X 2 Σ +, A 2 Π-X 2 Σ + GharibNezhad et al. MNRAS 432, 2043 (2013); 25,26 MgH Hinkle et al. ApJS 207, 26 (2013). 2. CN, 13 CN, C 15 N B 2 Σ + -X 2 Σ +, A 2 Π-X 2 Σ +, Brooke et al. ApJS 210, 23 (2014); Sneden et al., ApJS (submitted). 3. C 2, C 13 C d 3 Π-a 3 Π (Swan system), Brooke et al. JQSRT 124, 11 (2013); Ram et al. ApJS 211, 5 (2014). 4. CP A 2 П-X 2 Σ +, Ram et al. JQSRT 138, 107 (2014). 5. NH, vibration-rotation, Brooke et al. JCP (submitted). 6. OH, vibration-rotation (Meinel bands), Brooke et al. JQSRT (in preparation). 7. CH, 13 CH C 2 Σ + -X 2 Π, B 2 Σ - -X 2 Π, A 2 Δ-X 2 Π, vibration- rotation, Masseron et al. AA (in press).

Sunspot MgH A 2 Π-X 2 Σ Hinkle et al. ApJS 207, 26 (2013) On Earth and in Sun 24 Mg: 25 Mg: 26 Mg abundance is 79:10:11. The magnesium isotopic ratios are probes of the heavy element enrichment of the Universe. 25 Mg and 26 Mg are produced during He burning; 24 Mg is produced during carbon burning. Low abundances of heavy elements will result in more 24 Mg relative to 25 Mg and 26 Mg.

Full Calculation Method (James Brooke) Ab initio Electronic (transition) dipole moment function Case (b) vibrational wavefunctions and transition dipole moment matrix elements Einstein As and f-values – line list with positions and intensities + LEVEL Start PGOPHER Spectrum Molecular constants Line assignment and fit RKR 1 Potential energy curve fit Equilibrium constants End Case (a) matrix elements Hund’s case (b) to (a)

C 13 C d 3 Π-a 3 Π (Swan system) Ram et al. ApJS 211, 5 (2014) Fit of lines of Amiot (1983) for 0-0 Swan System and Islami and Amiot (1986), Amiot and Verges (1982) for Ballik-Ramsay System (b 3 Σ - -a 3 Π ) with PGOPHER. Used ab initio transition dipole moment function for C 2 from Brooke et al. JQSRT 124, 11 (2013). In addition used isotope relations as needed.

Carbon-Enhanced Metal Poor Stars (CEMP)  Big Bang created only the elements H, He and a trace of Li 13.7 billion years ago.  After few hundred million years first stars form (“Population III”) and heavy elements are synthesized by nuclear fusion, neutron reactions and supernova explosions.  Next generation of stars forms from interstellar clouds of ejected material (“Population II”); then same cycle as above.  Third generation of stars form like our Sun (“Population I”). Metallicity: Population I: [Fe/H]=~0; Population II: [Fe/H]<-1; Population III: [Fe/H]<-6

HE is CEMP star with [Fe/H]=-3.45 (i.e., Fe is depleted by more than 1000 relative to Sun) but [C/Fe]=1.8 (i.e., C is enhanced relative to Fe by a factor of 100, relative to Sun). 12 C/ 13 C is 3.5 (solar is 90). Probably mass transfer occurred from an AGB star in a binary system. Sneden’s MOOG code used.

CN B 2 Σ + -X 2 Σ + Δv=+2 Sequence CN lab spectra were recorded by S. Davis with Kitt Peak FTS using a microwave discharge of nitrogen with a trace of methane. Data was analyzed in a series of papers: Ram et al. JMS 263, 82 (2010); Ram et al. ApJS 188, 500 (2010); Ram & Bernath, ApJ 194, 34 (2011); Colin & Bernath, JMS 273, 30 (2012). Transition dipole moment calculated by Schwenke used to generate linelists for CN, 13 CN, C 15 N B 2 Σ + -X 2 Σ +, A 2 Π-X 2 Σ + transitions by Brooke et al. ApJS 210, 23 (2014); Sneden et al., ApJS (submitted).

Solar CN (Fraunhofer Lines) Absorption in photosphere of the Sun L. Wallace, Kitt Peak Solar Atlas T rot = 6000 K in the solar photosphere; [CN]/[ 13 CN]=90, same as on Earth; “Absolute” abundance is: log ε(X) = log 10 (N X /N H ) + 12 Asplund et al. (2009) recommend log ε(N) = 7.83±0.05 CN, 13 CN, C 15 N B 2 Σ + -X 2 Σ +, A 2 Π-X 2 Σ +, Brooke et al. ApJS 210, 23 (2014); Sneden et al., ApJS (submitted). B 2 Σ + -X 2 Σ +, 0-0 A 2 Π-X 2 Σ +, 2-0 A 2 Π-X 2 Σ +, 0-0

Nitrogen Abundance of Two CEMP Stars CN B 2 Σ + -X 2 Σ +, 0-1 band (Sneden et al. ApJS, submitted)

CH, A 2 Δ-X 2 Π Transition (G band) Constants for v’=4 and 5 derived from stellar spectra by Masseron et al. AA (in press).

CH in CEMP Stars CH, A 2 Δ-X 2 Π, Masseron et al. AA (in press); 4-4 and 5-5 bands identified for the first time A 2 Δ-X 2 Π 5-5 A 2 Δ-X 2 Π 4-4

Solar CH (1-0 Fundamental) ACE solar spectrum: Hase et al. JQSRT 111, 521 (2010) Herman-Wallis effect must be included using LEVEL (i.e., J-dep. of vibrational wavefunction)

APOGEE: Apache Point Observatory Galactic Evolution Experiment APOGEE will survey over 100,000 red giant stars and record spectra with R~22,500 in the μm region to obtain abundance of 15 chemical species.