! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 5865,v 8.1 1996/01/07 21:15:05 pepsa Exp $ ! ! Subject: NGC 5809 proposal Vers March 10 17:00 CET ! ! For help call your Program Coordinator: Karla Peterson ! Phone: 410 338-4774, E-mail: peterson@stsci.edu ! ! This partially completed template was generated from your Phase I proposal. ! Drafted for Phase II: Version 24/2/95 15:00 CEuroT Proposal_Information Title: NLTE analysis of the hot post-AGB star ZNG1 in the galactic globular cluster M 5 and search for a nebula Proposal_Category: GO Scientific_Category: Hot Stars Cycle: 5 Investigators PI_name: Ulrich Heber PI_Institution: Astronomisches Institut der Universitaet Erlangen-Nuernberg CoI_Name: Ralf Napiwotzki CoI_Institution: Astronomisches Institut der Universitaet Erlangen-Nuernberg Contact: ! Y or N (designate at most one contact) CoI_Name: Stefan Haas CoI_Institution: Astronomisches Institut der Universitaet Erlangen-Nuernberg Contact: ! Y or N (designate at most one contact) CoI_Name: Joachim Koeppen CoI_Institution: Institut fuer Theoretische Physik u. Sternwarte der Universitaet Kiel Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) UV spectroscopy of the blue star ZNG1 in the galactic globular cluster M 5 shows striking similarities to the two known Central stars in globular clusters (K 648 in M15 and GJJC1 in M22). A forbidden ion NIV emission in the IUE spectrum has led Bohlin et al. (1983, ApJ 267, L89) to postulate a PN around ZNG1. If this could be confirmed, ZNG1 would be only the third known PNN in a globular cluster. Imaging with the ESO-NTT has demonstrated that ZNG1 is double with a cool companion separated by only 0sec point4. Optical spectroscopy of the hot star turned out to be impossible even with the NTT under good seeing conditions. The existing low resolution IUE spectra are of insufficient quality for a fine abundance analysis. We propose to search for a nebula around ZNG1 with PC narrowband photometry. A spectroscopic analysis of GHRS-UV-spectra with state-of-the-art NLTE models is proposed to search amongst halo PAGB stars for correlations with metallicity as predicted by stellar evolution theory. The metallicity of M 5 is considerably larger than of the previously studied stars in M 15 and M 22. Questions ! Free format text (please update) Observing_Description: The absolute magnitude of the star can be determined from archival PC images in the V filter by making use of the known cluster distance. An additional PC images will be exposed through the narrowband filters to search for HAlpha emission. The exposure times for these images are estimated not to saturate the possible central star. Exposure time 10 min. for HAlpha. The star is visible for 52min. per orbit. The PC observation can be done in one orbit. Two GHRS exposures using grating G140L are required to cover the strategic metal lines and ionHeII 1640Angstrom. We aim at a S/N=40 (reddest part) to 90 (blue end). UV fluxes are from the IUE low resolution spectrum described by Bohlin et al. (1983). The first setting of the grating will cover 1150 Angstrom to 1436 Angstrom, while the second setting shall cover 1464 Angstrom to 1750 Angstrom. Exposure times required are 11 minutes for the first and 23 min. for the second exposure. The GHRS observations can be carried out during the same visit in a second orbit (guide star reacquisition 6min. + exposure time 34 min. + instrument overhead 8min = 52 min.). The quide star acquisition can be done at the end of the first orbit. Fixed_Targets Target_Number: 1 Target_Name: NGC5904-ZNG1 Alternate_Names: Description: STAR,SDO Position: RA=15H 18M 34.073S +/- 0.01S, DEC=+02D 04' 59.43" +/- 0.01" Equinox: J2000 Epoch: Flux: V=14.2 +/- 0.2,B-V=-0.2 +/- 0.2,E(B-V)=0.03 +/-0.01 Comments: HRS TARGET ZNG1 IN GLOBULAR CLUSTER M5 Coordinates have been derived from an archival PC-U-frame Accuracy of the coords. need to be checked. Visits Visit_Number: 1 Visit_Requirements: Visit_Comments: Exposure_Number: 1 Target_Name: NGC5904-ZNG1 Config: HRS Opmode: ACQ Aperture: 2.0 Sp_Element: MIRROR-N1 Wavelength: Optional_Parameters: SEARCH-SIZE=3,BRIGHT=RETURN Number_of_Iterations: 1 Time_Per_Exposure: 13.5S Special_Requirements: ONBOARD ACQ FOR 2-3 Comments: STEP-TIME=1.5S, EXPECT 600 CNTS Exposure_Number: 2 Target_Name: NGC5904-ZNG1 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1150-1436 Optional_Parameters: FP-SPLIT=STD,COMB=FOUR,DOPPLER=ON Number_of_Iterations: 1 Time_Per_Exposure: 870.4s Special_Requirements: Comments: Exposure time may be cut to allow exposures#4+5 in orbit2. Cut such that expo#3 remains about 2*expo#2. If to be cut below 10MIN notify PI. Exposure_Number: 3 Target_Name: NGC5904-ZNG1 Config: HRS Opmode: ACCUM Aperture: 2.0 Sp_Element: G140L Wavelength: 1464-1750 Optional_Parameters: FP-SPLIT=STD,COMB=FOUR,DOPPLER=ON Number_of_Iterations: 1 Time_Per_Exposure: 1632s Special_Requirements: Comments: Exposure time may be cut to allow exposures#4+5 in orbit2. Cut such that expo#3 remains about 2*expo#2. If to be cut below 20MIN notify PI. Exposure_Number: 4 Target_Name: NGC5904-ZNG1 Config: WFPC2 Opmode: IMAGE Aperture: PC1 Sp_Element: F656N Wavelength: 6563 Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 200S Special_Requirements: Comments: Exposure split into two. Do not cut further. Exposure_Number: 5 Target_Name: NGC5904-ZNG1 Config: WFPC2 Opmode: IMAGE Aperture: PC1 Sp_Element: F656N Wavelength: 6563 Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 300S Special_Requirements: Comments: Exposure split into two. Do not cut further. Data_Distribution Medium: 8MM Blocking_Factor: 10 Ship_To: PI_Address