13827( 3) - 28-Sep-2015 18:12:08 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13827 Version: 3 Check-in Time: 28-Sep-2015 18:12:08 STScI Edit Number: 0 Title A New Opportunity to Detect Iron in the Most Iron-Poor Star Known ------------------------------------------------------------------------------------ Type Cycle GO 22 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Ian U. Roederer University of Michigan Y ------------------------------------------------------------------------------------ Abstract At present, there are three stars known in the Milky Way with Fe/H ratios less than 1/100, 000 times the Solar Fe/H ratio. These stars were almost certainly formed during the earliest epochs of star formation in the Milky Way, and their metals were formed from the yields of just one zero-metallicity Population III supernova. High-quality optical spectroscopy reveals the presence of C, Mg, Ca, Fe, and other metals in two of these stars. In the most iron-poor star, SMSS J031300-670839, only Li, C, Mg, and Ca are detected. Not a single iron line can be detected in the optical spectral range. The Fe/H ratio of this star is currently estimated to be less than 1/13, 000, 000 times the Solar Fe/H ratio. I propose to obtain a high-resolution COS spectrum of this star to attempt to detect Fe II lines in the NUV near 2400 Angstroms. These Fe II lines are the strongest of any iron-group element, and they present the best opportunity to detect iron in this star. My proposed observations would tighten the constraint on the Fe/H ratio by a factor of 50, and a detection would be possible if the Fe/H ratio in this star is 1/1, 000, 000, 000 times the Solar Fe/H ratio or greater. NUV observations with COS provide the only opportunity to perform this study. ------------------------------------------------------------------------------------ Observations Description ------------------------ This program will obtain R~22, 000 COS spectra around several Fe II absorption lines near 2400 Angstroms in a very metal-poor late-G-type star. The goal is to obtain the highest S/N possible (target: S/N ~ 20/1) in this one setup within the 10 orbits allocated. ------------------------------------------------------------------------------------ 13827( 3) - 28-Sep-2015 18:12:08 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 SMSS-J031300 STAR, G III-I, HALO, RA=03H13M0.3600S +/- 0.2", J2000 V = -334 V = 14.7 +/- 0.1 E(B-V) = 0.04; B = -670839 POPULATION II DEC=-67D08'39.33" +/- 0.2" 15.36 (USNO-B); R = 14.10 (USNO-B); J = 13.181 (2MASS); H = 12.692 (2MASS); K = 12.661 (2MASS) Reference Frame: ICRS Extended: NO Comments: The coordinates are taken from the USNO-B catalog accessed through IRSA on 07 July 2014. The proper motions derived by the PPMXL catalog (USNO-B plus 2MASS) are PMRA = -0.000002 +/- 0.000003 deg/yr and PMDEC = 0.000002 +/- 0.000003 deg/yr. Neither one is significant, so I have entered 0.0 for both values in the APT table. The coordinate uncertainties are given as 0.000018 deg (*cos(DEC)), which I convert to 0.17 arcsec. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1994.35 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 13827( 3) - 28-Sep-2015 18:12:08 - [ 3] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SMSS-J03130 COS/NUV ACQ/IMA PSA MIRRORA 1 66 S (66 0-670839 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SMSS-J03130 COS/NUV TIME-TA PSA G225M 2390 BUFFER-TIME=948, FLASH=YES, 1 2953 S 0-670839 G FP-POS=1 see below (2828 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SMSS-J03130 COS/NUV TIME-TA PSA G225M 2390 BUFFER-TIME=1071, FLASH=YES, 1 3323 S 0-670839 G FP-POS=2 see below (3307 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 SMSS-J03130 COS/NUV TIME-TA PSA G225M 2390 BUFFER-TIME=1071, FLASH=YES, 1 3323 S 0-670839 G FP-POS=3 see below (3307 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 SMSS-J03130 COS/NUV TIME-TA PSA G225M 2390 BUFFER-TIME=1071, FLASH=YES, 1 3323 S 0-670839 G FP-POS=3 see below (3307 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 SMSS-J03130 COS/NUV TIME-TA PSA G225M 2390 BUFFER-TIME=1071, FLASH=YES, 1 3323 S 0-670839 G FP-POS=4 see below (3307 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SMSS-J031300-670839 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE SMSS-J031300-670839 2 COS/NUV TIME-TA PSA G225M 2390 none none none none 1 2828.0 S G SMSS-J031300-670839 3 COS/NUV TIME-TA PSA G225M 2390 none none none none 2 3307.0 S G SMSS-J031300-670839 4 COS/NUV TIME-TA PSA G225M 2390 none none none none 3 3307.0 S G SMSS-J031300-670839 5 COS/NUV TIME-TA PSA G225M 2390 none none none none 4 3307.0 S G SMSS-J031300-670839 6 COS/NUV TIME-TA PSA G225M 2390 none none none none 5 3307.0 S G 13827( 3) - 28-Sep-2015 18:12:08 - [ 4] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 SMSS-J03130 COS/NUV ACQ/IMA PSA MIRRORA 1 66 S (66 0-670839 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 SMSS-J03130 COS/NUV TIME-TA PSA G225M 2390 BUFFER-TIME=948, FLASH=YES, 1 2953 S 0-670839 G FP-POS=1 see below (2828 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 SMSS-J03130 COS/NUV TIME-TA PSA G225M 2390 BUFFER-TIME=1071, FLASH=YES, 1 3323 S 0-670839 G FP-POS=2 see below (3307 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 SMSS-J03130 COS/NUV TIME-TA PSA G225M 2390 BUFFER-TIME=1071, FLASH=YES, 1 3323 S 0-670839 G FP-POS=2 see below (3307 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 SMSS-J03130 COS/NUV TIME-TA PSA G225M 2390 BUFFER-TIME=1071, FLASH=YES, 1 3323 S 0-670839 G FP-POS=3 see below (3307 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 SMSS-J03130 COS/NUV TIME-TA PSA G225M 2390 BUFFER-TIME=1071, FLASH=YES, 1 3323 S 0-670839 G FP-POS=4 see below (3307 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ SMSS-J031300-670839 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE SMSS-J031300-670839 2 COS/NUV TIME-TA PSA G225M 2390 none none none none 1 2828.0 S G SMSS-J031300-670839 3 COS/NUV TIME-TA PSA G225M 2390 none none none none 2 3307.0 S G SMSS-J031300-670839 4 COS/NUV TIME-TA PSA G225M 2390 none none none none 3 3307.0 S G SMSS-J031300-670839 5 COS/NUV TIME-TA PSA G225M 2390 none none none none 4 3307.0 S G SMSS-J031300-670839 6 COS/NUV TIME-TA PSA G225M 2390 none none none none 5 3307.0 S G 13827( 3) - 28-Sep-2015 18:12:08 - [ 5] Summary Form for Proposal 13827 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1071, BUFFER-TIME=948, FLASH=YES, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G225M, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names SMSS-J031300-670839 ------------------------------------------------------------------------------------------------------------------------------------