Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 2009c Report Date: 09-May-96:16:51 Version: ********** Check-in Date: ********** 1.Proposal Title: MASS LOSS IN LUMINOUS GLOBULAR CLUSTER STARS ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID STELLAR ASTROPHYSICS GO Sub Category STELLAR ATMOSPHERES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Prof. Erika Bohm-vitense WASHINGTON, UNIVERSITY OF USA (206) 543-4858 PROFESSOR ------------------------------------------------------------------------------------ 7. Abstract We want to study the mass loss for stars at the tip of the red giant branch in globular clusters. It is well known that red giant stars in globular clusters need to lose mass in order to become blue horizontal branch stars. While we do not yet understand the mass loss mechnism we suspect that it takes place at the tip of the red giant branch where the gravitational binding of the atmospheric layers becomes small. Gratton,Pilachowski and Sneden (1984)find a correlation between H-alpha emission being observed for luminous stars on the red giant branch in globular clusters and the existence of a blue horizontal branch. We therefore suspect that mass loss and H-alpha emission are correlated. We want to check this by observing the Mg II line profiles at 2800 A in order to see whether "blue" shifted absorption components can be seen which are indicative of a strong mass loss and whether this mass loss, if present, is correlated with H-alpha emission and with the existence of a blue horizontal branch. ------------------------------------------------------------------------------------ 8. Scientific Key Words: STARS, POPULATION II, GIANTS, MASS LOSS ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 3.00 par: 0 10. Num targs pri: 3 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS WF/PC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 2009c PI: Prof. Erika Bohm-vitense Proposal Title: MASS LOSS IN LUMINOUS GLOBULAR CLUSTER STARS ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ P.I. Erika Bohm-Vitense WASHINGTON, UNIVERSITY OF USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We would like to take 1 WFC image of the star W 76 in 47 Tuc and the field around it at 2800 A for better target recognition and in order to see whether anything peculiar occurs in the surroundings of the target. This image will also give us a better estimate for the fluxes at 2800 A. The main object is the study of the MG II line profiles at 2800 A of the 4 target stars. We threfore want to take spectra of the target stars with the HRS and the G270M grating. ------------------------------------------------------------------------------------ 11. Address Information Name: ERIKA BOHM-VITENSE Category: PI Institution: UNIVERSITY OF WASHINGTON Address: ASTRONOMY DEPT. FM-20 City: SEATTLE State: WA Zip Code: 98195 Country: USA Telephone: (206) 543-4858 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 2009c [ 3] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC6397-211 STAR:RED GIANT:POP II PLATE-ID=8729, 2000 1 F-CONT(2800) = 1.2 +/- 0.9 E-14 RA = 17H 41M 25.56S +/- 2 V =10.2 +/- 0.3, B-V=1.5, E(B- 0.3", DEC = V)=0.17 -53D 37' 38.43" +/- 0.3" ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC6397-603 STAR: RED GIANT: POP II PLATE-ID=8729, 2000 1 F-CONT(2800) = 1.0 +/- 0.8 E-14 RA = 17H 40M 38.82S +/- 2 V = 10.4 +/- 0.3, B-V=1.33, E(B- 0.3", DEC = V)=0.17 -53D 45' 25.51" +/- 0.3" ------------------------------------------------------------------------------------------------------------------------------------ 3 47TUC-W76 STAR: RED GIANT: POP II PLATE-ID=9173, 2000 1 F-CONT(2800) = 3.0 +/- 2.3 E-15 RA = 00H 24M 03.21S +/- 5", 2 V = 11.5 +/- 0.3, B-V=1.58, E(B- DEC = -71D V)=0.04 55' 47.04" +/- 5" ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 2009c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 47TUC-W76 WFC IMAGE ALL F284W 1 6.0M 15 1 1 EARLY ACQ FOR 7 Comments: EARLY ACQUISITION FOR 7 EARLY FLUX ESTIMATE FOR 7 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC6397-211 HRS ACQ 2.0 MIRROR-N2 FAINT=60 1 54.0S 5 1 1 ONBOARD ACQ FOR 3 DARK TIME ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC6397-211 HRS ACCUM 2.0 G270M 2800 3 10.6M 10 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC6397-603 HRS ACQ 2.0 MIRROR-N2 FAINT=60 1 60.S 5 2 1 ONBOARD ACQ FOR 5 DARK TIME ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC6397-603 HRS ACCUM 2.0 G270M 2800 3 11.7M 10 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 6 47TUC-W76 HRS ACQ 2.0 MIRROR-N2 FAINT=60 1 72S 5 1 2 ONBOARD ACQ FOR 7 DARK TIME ------------------------------------------------------------------------------------------------------------------------------------ 7 47TUC-W76 HRS ACCUM 2.0 G270M 2800 3 13.3M 10 1 2 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 2009c [ 5] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFC HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FAINT=60 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR ASTROPHYSICS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category STELLAR ATMOSPHERES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements EARLY ACQ FOR 7; ONBOARD ACQ FOR 3; DARK TIME ONBOARD ACQ FOR 5; DARK TIME ONBOARD ACQ FOR 7; DARK TIME ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F284W MIRROR-N2 G270M ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC6397-211 NGC6397-603 47TUC-W76 ------------------------------------------------------------------------------------------------------------------------------------