13708( 3) - 18-Jul-2014 16:19:24 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13708 Version: 3 Check-in Time: 18-Jul-2014 16:19:24 STScI Edit Number: 1 Title Following the rapid evolution of the central star of the Stingray Nebula in real time ------------------------------------------------------------------------------------ Type Cycle GO 22 ------------------------------------------------------------------------------------ Investigators Contact? PI: Ms. Nicole Reindl Eberhard Karls Universitat, Tubingen Y CoI: Prof. Klaus Werner Eberhard Karls Universitat, Tubingen N CoI: Dr. Thomas Rauch Eberhard Karls Universitat, Tubingen N CoI: Dr. Marcelo Miguel Miller Max-Planck-Institut fur Astrophysik N Bertolami CoI: Dr. Mudumba Parthasarathy Indian Institute of Astrophysics N ------------------------------------------------------------------------------------ Abstract SAO 244567 is an unusually fast evolving star. Within twenty years only, it has turned from a B-type supergiant into the central star of the Stingray nebula. Space and ground-based observations obtained over the last decades have revealed that its spectrum changes noticeably over just a few years, showing stellar evolution in real time. Previous analysis indicates it must be a low mass star and thus the observed fast evolution is in strong contradiction with canonical post-asymptotic giant branch (AGB) evolution. A late He-shell flash is able to account for the rapid evolution. This scenario would predict an evolution back to the AGB, e.g. a decrease of the effective temperature (which is already indicated by the FUSE observations in 2006) and an increase of luminosity. With COS spectroscopy we want to follow the evolution of the surface properties of SAO 244567 to verify this thesis. The very compact nebula of SAO 244567 makes it impossible to derive these parameters from optical spectra, because most of the photospheric lines are blended by nebular emission lines thus they are not suitable for a spectral analysis. The derived surface parameters will establish constraints for late thermal pulse evolutionary calculations. With these calculations we aim not only to explain the nature of SAO 244567, but they also will provide a deeper insight in the formation process of hydrogen deficient stars, which make up 25% of the post AGB-stars and white dwarfs. ------------------------------------------------------------------------------------ Observations Description ------------------------ FUV (medium and low resolution) and NUV (low resolution) spectra of SAO244567 (star) shall be observed within 1 visit. Orbit 1 to 4: COS/PSA G130M with central wavelength 1222 A. One different FP-POS per orbit. Orbit 5: COS/PSA G140L with central wavelength 1280 A. COS/PSA G230L with central wavelengths 3360 A and 2635 A. ------------------------------------------------------------------------------------ 13708( 3) - 18-Jul-2014 16:19:24 - [ 2] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NAME-STINGRA STAR, PLANETARY NEBULA RA=17H16M21.0800S +/- 1", J2000 V = 15.0 +/- 0.8 f_max(at 1200A) = Y-NEBULA CENTRAL STAR DEC=-59D29'23.30" +/- 1" 3.2*10^-13 erg cm^2 s^-1 A^-1, f_min (at 1200A) = 0.8 *10^-13 erg cm^2 s^-1 A^-1 Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.0 0.0 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 13708( 3) - 18-Jul-2014 16:19:24 - [ 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 NAME-STINGR COS/FUV ACQ/SEA PSA G130M 1291 CENTER=FLUX-WT-FLR, 1 0.7 S (0.7 AY-NEBULA RCH SCAN-SIZE=4, STEP-SIZE=1.767, S) SEGMENT=BOTH ------------------------------------------------------------------------------------------------------------------------------------ 2 NAME-STINGR COS/FUV ACQ/PEA PSA G130M 1291 SEGMENT=BOTH 1 0.7 S (0.7 AY-NEBULA KXD S) ------------------------------------------------------------------------------------------------------------------------------------ 3 NAME-STINGR COS/FUV ACQ/PEA PSA G130M 1291 SEGMENT=BOTH, 1 0.7 S (0.7 AY-NEBULA KD CENTER=FLUX-WT-FLR, NUM-POS=5, S) STEP-SIZE=0.9 ------------------------------------------------------------------------------------------------------------------------------------ 4 NAME-STINGR COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=169, EXTENDED=NO, 1 2138 S AY-NEBULA G FLASH=YES, FP-POS=1, (2138 S) SEGMENT=BOTH ------------------------------------------------------------------------------------------------------------------------------------ 5 NAME-STINGR COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=169, EXTENDED=NO, 1 3184 S AY-NEBULA G FLASH=YES, FP-POS=2, (3184 S) SEGMENT=BOTH ------------------------------------------------------------------------------------------------------------------------------------ 6 NAME-STINGR COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=169, EXTENDED=NO, 1 3184 S AY-NEBULA G FLASH=YES, FP-POS=3, (3184 S) SEGMENT=BOTH ------------------------------------------------------------------------------------------------------------------------------------ 7 NAME-STINGR COS/FUV TIME-TA PSA G130M 1222 BUFFER-TIME=169, EXTENDED=NO, 1 3184 S AY-NEBULA G FLASH=YES, FP-POS=4, (3184 S) SEGMENT=BOTH ------------------------------------------------------------------------------------------------------------------------------------ 8 NAME-STINGR COS/FUV TIME-TA PSA G140L 1280 BUFFER-TIME=120, EXTENDED=NO, 1 187 S (748 AY-NEBULA G FLASH=YES, SEGMENT=BOTH, S) FP-POS=ALL ------------------------------------------------------------------------------------------------------------------------------------ 9 NAME-STINGR COS/NUV TIME-TA PSA G230L 3360 BUFFER-TIME=174, EXTENDED=NO, 1 500 S (500 AY-NEBULA G FLASH=YES, FP-POS=3 S) ------------------------------------------------------------------------------------------------------------------------------------ 10 NAME-STINGR COS/NUV TIME-TA PSA G230L 2635 BUFFER-TIME=374, EXTENDED=NO, 1 494 S (494 AY-NEBULA G FLASH=YES, FP-POS=3 S) ------------------------------------------------------------------------------------------------------------------------------------ 13708( 3) - 18-Jul-2014 16:19:24 - [ 4] 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 | ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ NAME-STINGRAY-NEBUL 1 COS/FUV ACQ/SEA PSA G130M 1291 none none none none 1 N/A A RCH NAME-STINGRAY-NEBUL 2 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A A KXD NAME-STINGRAY-NEBUL 3 COS/FUV ACQ/PEA PSA G130M 1291 none none none none 1 N/A A KD NAME-STINGRAY-NEBUL 4 COS/FUV TIME-TA PSA G130M 1222 none none none none 1 N/A A G NAME-STINGRAY-NEBUL 5 COS/FUV TIME-TA PSA G130M 1222 none none none none 2 N/A A G NAME-STINGRAY-NEBUL 6 COS/FUV TIME-TA PSA G130M 1222 none none none none 3 N/A A G NAME-STINGRAY-NEBUL 7 COS/FUV TIME-TA PSA G130M 1222 none none none none 4 N/A A G NAME-STINGRAY-NEBUL 8 COS/FUV TIME-TA PSA G140L 1280 none none none 1 5 N/A A G NAME-STINGRAY-NEBUL 8 COS/FUV TIME-TA PSA G140L 1280 none none none 2 5 N/A A G NAME-STINGRAY-NEBUL 8 COS/FUV TIME-TA PSA G140L 1280 none none none 3 5 N/A A G NAME-STINGRAY-NEBUL 8 COS/FUV TIME-TA PSA G140L 1280 none none none 4 5 N/A A G NAME-STINGRAY-NEBUL 9 COS/NUV TIME-TA PSA G230L 3360 none none none none 5 N/A A G NAME-STINGRAY-NEBUL 10 COS/NUV TIME-TA PSA G230L 2635 none none none none 5 N/A A G 13708( 3) - 18-Jul-2014 16:19:24 - [ 5] Summary Form for Proposal 13708 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAKD, ACQ/PEAKXD, ACQ/SEARCH, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=120, BUFFER-TIME=169, BUFFER-TIME=174, BUFFER-TIME=374, CENTER=FLUX-WT-FLR, EXTENDED=NO, FLASH=YES, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4, FP-POS=ALL, NUM-POS=5, SCAN-SIZE=4, SEGMENT=BOTH, STEP-SIZE=0.9, STEP-SIZE=1.767 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, G140L, G230L ------------------------------------------------------------------------------------------------------------------------------------ Target Names NAME-STINGRAY-NEBULA ------------------------------------------------------------------------------------------------------------------------------------