5885( 4) - 09/22/95 11:34 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5885 Version: 4 Check-in Date: ********** 1.Proposal Title: GHRS-Observations of candidate Beta Pictoris-like circumstellar gaseous disk ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Interstellar Medium GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Alain Lecavelier Des Etangs Institut d'Astrophysique de Paris CoI: D Backman NASA Ames Research Center N CoI: A. Vidal-Madjar Institut d'Astrophysique de Paris N CoI: R. Ferlet Institut d'Astrophysique de Paris N CoI: A. Lagrange-Henri Observatoire de Grenoble N CoI: H. Beust Observatoire de Grenoble N CoI: D. Mouillet Observatoire de Grenoble N CoI: M. Deleuil Laboratoire d'Astrophysique de Marseille N CoI: J Lissauer State University of New-York N ------------------------------------------------------------------------------------ 6. Abstract The gaseous parts of dust disks surrounding main sequence stars have been the subject of intense investigations since 1985. The spectral signatures of Beta Pictoris led to the explanation that the gas content whose origin was a puzzle in such an evolved disk is produced by the evaporation of many small bodies. A way to progress in that field is to search for gas signatures in the environment of other stars presenting known IR excesses or shell characteristics. This study was started from the ground and should be continued now in the UV where stronger lines are available. From ground- based observations, we have shown that four stars present weak circumstellar gas signatures (Lagrange-Henri et al 1990). More recently, two additionnal candidates were discovered in an optical survey of the local interstellar medium. But from the ground, it is clear that having access to essentially only the CaII lines is a strong limitation. The UV observation of these lines of sight will give us a detailed view of the circumstellar material. The inconsistent conclusions about possible gas absorption towards Alpha PsA with IUE and GHRS show the limitation of IUE Studies. Here we propose GHRS observations of four of these stars in order to confirm the existence of the circumstellar gas, to improve our knowledge of such gaseous disk, and to understand the origin of this gas at somewhat later stages of the stellar evolution. ------------------------------------------------------------------------------------ 5885( 4) - 09/22/95 11:34 - [ 2] Observations Description ------------------------ To detect the gaseous atmosphere of the disk and to have a view of the physical state of the circumstellar material around the selected stars, we propose to look at the following very strong UV lines with LSA and ECH-B: Fe II fine structure (385 cm-1) 2598.4A. and (667 cm-1) 2607A., in the same domain the Mn II multiplet at 2600A. The Mg II doublet 2802.7A and 2795.5A. The presence of gas absorption from Fe II excited levels is a strong signature of the circumstellar origin while absorptions from excited fine-structure levels require densities incompatible with those find in the interstellar medium., The following table presents the flux (10E-11erg.s-1.cm-2A.-1), the exposure time (t_e) and S/N at the bottom of the lines. star (HR) 10 2174 6519 8675, ---- -------------------------------------------------- Flux at 2600A. 0.10 0.24 1.1 1.8 Flux at 2800A. 0.09 0.20 0.7 1.5 S/N 20 30 40 50 t_e (s) at 2600A. 326.4 326.4 108.8 108.8 t_e (s) at 2800A. 389 391 202 108.8 In addition and for only the two best candidates (HR 8675 and HR 6519: 51 Oph), we propose to observe with G160M the 1550A. region to search for CO, C I and C IV signatures. star Lambda S/N t_e ----------------------------------------- ---------- HR 6519 GM160 1550 A 40 108.8 HR 8675 GM160 1550 A 50 407 These observations will allow to compare the velocity field of different species. Indeed, these stars have already shown redshift variable absorption features (Lagrange-Henri et al. 1990b and Grady et al. 1993), and from our Beta Pic analysis, we have shown that there are strong differences between the ionised species like C IV or Al III which show very large redshift and are probably associated with comets-size bodies (Beust et al 1991, Beust and Tagger 1993), and the other species like C I which are mainly at rest. Real Time Justification ----------------------- None None. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5885( 4) - 09/22/95 11:34 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD256 STAR, DISK RA=00H 07M 18.27S +/- 0.01S, J2000 V=0 V=6.2 DEC=-17D 23' 13.1" +/- 0.1" TYPE=A6V B-V=0.14 F-CONT(2600)=0.42E-11 F-CONT(2800)=0.53E-11 Comments: Coordinates from Hipparcos INCA 4/12/95 2 HD42111 STAR, DISK RA=06H 08M 57.88S +/- 0.01S, J2000 V=+34 V=5.7 DEC=02D 29' 58.9" +/- 0.1" TYPE=A3V B-V=0.07 F-CONT(2600)=0.95E-11 F-CONT(2800)=1.2E-11 Comments: Coordinates from Hipparcos INCA 4/12/95 3 HD158643 STAR, DISK RA=17H 31M 24.96S +/- 0.01S, J2000 V=-12 V=4.8 DEC=-23D 57' 45.7" +/- 0.1" TYPE=B9.5V B-V=0.00 F-CONT(2600)=4.3E-11 F-CONT(2800)=4.3E-11 Comments: Coordinates from Hipparcos INCA 4/12/95 4 HD215789 STAR, DISK RA=22H 48M 33.30S +/- 0.01S, J2000 V=-3 V=3.49 DEC=-51D 19' 0.6" +/- 0.1" TYPE=A3V B-V=0.08 F-CONT(2600)=7.1E-11 F-CONT(2800)=9.0E-11 Comments: Coordinates from Hipparcos INCA 4/12/95 5885( 4) - 09/22/95 11:34 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD256 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN 1 1.8S ONBOARD ACQ FOR 20 LOCATE=DEF SEARCH-SIZE=3 Comments: STEP-TIME=0.2 => Count=1.8e5 ------------------------------------------------------------------------------------------------------------------------------------ 20 HD256 HRS ACQ/PEA 0.25 MIRROR-N2 1 5S ONBOARD ACQ FOR 32-42 KUP Comments: STEP-TIME=0.2 => Count=1.2e5 ------------------------------------------------------------------------------------------------------------------------------------ 32 HD256 HRS ACCUM 0.25 ECH-B 2603.5 FP-SPLIT=STD 1 326.4S STEP-PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 42 HD256 HRS ACCUM 0.25 ECH-B 2800.5 FP-SPLIT=STD 1 389S STEP-PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5885( 4) - 09/22/95 11:34 - [ 5] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD42111 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN 1 1.8S ONBOARD ACQ FOR 20 LOCATE=DEF SEARCH-SIZE=3 Comments: STEP-TIME=0.2 => Count=3.4e5 ------------------------------------------------------------------------------------------------------------------------------------ 20 HD42111 HRS ACQ/PEA 0.25 MIRROR-N2 1 5S ONBOARD ACQ FOR 32-42 KUP Comments: STEP-TIME=0.2 => Count=2.2e5 ------------------------------------------------------------------------------------------------------------------------------------ 32 HD42111 HRS ACCUM 0.25 ECH-B 2603.5 FP-SPLIT=STD 1 326.4S STEP-PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 42 HD42111 HRS ACCUM 0.25 ECH-B 2800.5 FP-SPLIT=STD 1 391S STEP-PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5885( 4) - 09/22/95 11:34 - [ 6] Visit: 03 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD158643 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN 1 1.8S ONBOARD ACQ FOR 20 LOCATE=DEF SEARCH-SIZE=3 Comments: STEP-TIME=0.2 => Count=1.2e6 ------------------------------------------------------------------------------------------------------------------------------------ 20 HD158643 HRS ACQ/PEA 0.25 MIRROR-N2 1 5S ONBOARD ACQ FOR 32-52 KUP Comments: STEP-TIME=0.2 => Count=8.0e5 ------------------------------------------------------------------------------------------------------------------------------------ 32 HD158643 HRS ACCUM 0.25 ECH-B 2603.5 FP-SPLIT=STD 1 108.8S STEP-PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 42 HD158643 HRS ACCUM 0.25 ECH-B 2800.5 FP-SPLIT=TWO 1 252S STEP-PATT=DEF Comments: The time is computed in order to use the target visibility as much as possible and must be expanded to 5x54.4s= 272s if possible. ------------------------------------------------------------------------------------------------------------------------------------ 52 HD158643 HRS ACCUM 0.25 G160M 1550 FP-SPLIT=STD 1 108.8S STEP-PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5885( 4) - 09/22/95 11:34 - [ 7] Visit: 04 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD215789 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN 1 1.8S ONBOARD ACQ FOR 20 LOCATE=DEF SEARCH-SIZE=3 Comments: STEP-TIME=0.2 => Count=2.5e6 ------------------------------------------------------------------------------------------------------------------------------------ 20 HD215789 HRS ACQ/PEA 0.25 MIRROR-N2 1 5S ONBOARD ACQ FOR 32-52 KUP Comments: STEP-TIME=0.2 => Count=1.6e6 ------------------------------------------------------------------------------------------------------------------------------------ 32 HD215789 HRS ACCUM 0.25 ECH-B 2603.5 FP-SPLIT=STD 1 108.8S STEP-PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 42 HD215789 HRS ACCUM 0.25 ECH-B 2800.5 FP-SPLIT=STD 1 108.8S STEP-PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 52 HD215789 HRS ACCUM 0.25 G160M 1550 FP-SPLIT=STD 1 407S STEP-PATT=DEF Comments: The time is computed in order to use the target visibility as much as possible and must be expanded to 4x108.8s= 435.2s if possible. ------------------------------------------------------------------------------------------------------------------------------------ 5885( 4) - 09/22/95 11:34 - [ 8] Visit: 05 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD158643 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN 1 1.8S ONBOARD ACQ FOR 20 LOCATE=DEF SEARCH-SIZE=3 Comments: STEP-TIME=0.2 => Count=1.2e6 ------------------------------------------------------------------------------------------------------------------------------------ 20 HD158643 HRS ACQ/PEA 0.25 MIRROR-N2 1 5S ONBOARD ACQ FOR 32-52 KUP Comments: STEP-TIME=0.2 => Count=8.0e5 ------------------------------------------------------------------------------------------------------------------------------------ 32 HD158643 HRS ACCUM 0.25 ECH-B 2603.5 FP-SPLIT=STD 1 108.8S STEP-PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 42 HD158643 HRS ACCUM 0.25 ECH-B 2800.5 FP-SPLIT=TWO 1 252S STEP-PATT=DEF Comments: The time is computed in order to use the target visibility as much as possible and must be expanded to 5x54.4s= 272s if possible. ------------------------------------------------------------------------------------------------------------------------------------ 52 HD158643 HRS ACCUM 0.25 G160M 1550 FP-SPLIT=STD 1 108.8S STEP-PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5885( 4) - 09/22/95 11:34 - [ 9] Summary Form for Proposal 5885 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAKUP ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN LOCATE=DEF SEARCH-SIZE=3 FP-SPLIT=STD STEP-PATT=DEF FP-SPLIT=TWO STEP-PATT=DEF ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Interstellar Medium ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 20 ONBOARD ACQ FOR 32-42 ONBOARD ACQ FOR 32-52 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 ECH-B G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD256 HD42111 HD158643 HD215789 ------------------------------------------------------------------------------------------------------------------------------------