9339( 4) - 02/20/02 10:15 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9339 Version: 4 Check-in Date: 20-Feb-2002 10:15:09 1.Proposal Title: Physical Parameters of the Erupting Luminous Blue Variable NGC 2363-V1 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 11 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Laurent Drissen Universite Laval CoI: Dr. Paul Crowther University College London N CoI: Dr. Carmelle Robert Universite Laval N CoI: Dr. Linda Smith University College London N CoI: Dr. Luc Dessart Universite Laval N CoI: Dr. Jean-Rene Roy Gemini Observatory N ------------------------------------------------------------------------------------ 5. Abstract In 1996, we reported the discovery of a bright variable star in the giant extragalactic H , ii region NGC 2363. Subsequent photometry and high quality HST/STIS spectroscopy of this star, NGC 2363-V1, revealed that we are witnessing a significant event in the evolution of a massive star, namely a major eruption of a Luminous Blue Variable (LBV). A quantitative analysis of the STIS datasets gathered in 1997 and 1999 allowed us to determine the luminosity, mass loss rate, wind terminal velocity, surface temperature and even Fe content of this erupting LBV. Because such events are rare, continuous monitoring of the physical parameters of NGC 2363- V1 over the course of its present eruption will provide an invaluable set of constraints for theoretical models. We therefore propose to obtain high quality STIS spectra of this star once a year for the next three observing Cycles. ------------------------------------------------------------------------------------ 9339( 4) - 02/20/02 10:15 - [ 2] Observations Description ------------------------ underlineAcquisition: The acquisition procedure followed succesfully in previous cycles is as follows: since we know the relative position of V1 and other isolated stars in the field to better than 0.05'' from our cycle 6 WFPC2 images, we will first acquire an isolated star 1 arcmin from V1, then move to V1, peak-up on it and observe. The long slit will be used, with the 0.2'' width to exclude as much nebular background as possible. \medskip underlineExposure times: Using the STIS ETC on the WWW, and assuming a B5I spectrum and V=18.2, we have determined the following exposure times to get a S/N of 25-30: G140L: 130M; G230L: 90M; G430L: 35M; G750L: 30M; G750M: 50M; G430M: 130M. These exposure times yielded excellent quality spectra for the quantitative analysis in Cycles 7-9. The times have been ajusted to efficiently fill the orbits, and amount to a total of 11 orbits, including acquisition and overheads. The STIS/CCD and STIS/MAMA observations are split into two visits, separated by less than 3 weeks, in order to follow the SAA guidelines without being too sensitive to the star's variability. One series of spectra for each of cycles 10, 11 and 12 will be obtained to monitor the long-term evolution of the star. Real Time Justification ----------------------- Since the star is variable (on timescales of months), we would like to obtain the optical (STIS/CCD) and ultraviolet (STIS/NUV, STIS/FUV) spectra within three weeks of each other. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9339( 4) - 02/20/02 10:15 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC2363-V1 EXT-STAR, Luminous Blue RA=07H 28M 43.36S +/- 0.03S, J2000 V=+180 V = 18.0 Variable DEC=69D 11' 23.95" +/- 0.05", B-V = 0.0 PLATE-ID=01KS Coordinate Source: HST_IMAGE Comments: Long-term variable. Could vary between V=20 and V=17, spectral type from O5 (when faint) to A0 (when bright). This star has been more or less s table at V=18 since 1995, but could drop back to V=20 within a year or two. 2 NGC2363- EXT-STAR RA=07H 28M 46.48S +/- 0.05S, J2000 V=+180 V = 17.0 OFFSET DEC=69D 12' 38.03" +/- 0.1", B-V = 0.0 PLATE-ID=01KS Coordinate Source: HST_IMAGE 9339( 4) - 02/20/02 10:15 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.55 Coordinate_Frame POS-TARG Pattern_Orient 90 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 9339( 4) - 02/20/02 10:15 - [ 5] Visit: 01 Visit Priority: Visit Requirements: GROUP 01-02 WITHIN 20 D On Hold Comments: Additional Comments: The target star is variable; the amplitude and timescale of the spectroscopic variations are unknown. Therefore, the observations at short and long wavelength should be made within a few weeks of each other. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC2363-OFF STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 5.0 S SET CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC2363-V1 STIS/C ACQ/PEA 52X0.2 MIRROR 1 25.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC2363-V1 STIS/C ACCUM 52X0.2 G750L 7751 CR-SPLIT=3 1 37 M CD ------------------------------------------------------------------------------------------------------------------------------------ 35 CCDFLAT STIS/C ACCUM 0.3X0.0 G750L 7751 2 DEF CD 9 ------------------------------------------------------------------------------------------------------------------------------------ 40 NGC2363-V1 STIS/C ACCUM 52X0.2 G430L 4300 CR-SPLIT=3 1 3045 S CD ------------------------------------------------------------------------------------------------------------------------------------ 50 NGC2363-V1 STIS/C ACCUM 52X0.2 G750M 6768 CR-SPLIT=3 1 3045 S CD ------------------------------------------------------------------------------------------------------------------------------------ 60 NGC2363-V1 STIS/C ACCUM 52X0.2 G430M 4451 CR-SPLIT=3 1 3045 S PATTERN 1 CD ------------------------------------------------------------------------------------------------------------------------------------ 9339( 4) - 02/20/02 10:15 - [ 6] Visit: 02 Visit Priority: Visit Requirements: GROUP 01-02 WITHIN 20 D On Hold Comments: Additional Comments: The target star is variable; the amplitude and timescale of the spectroscopic variations are unknown. Therefore, the observations at short and long wavelength should be made within a few weeks of each other. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC2363-OFF STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 5.0 S SET CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC2363-V1 STIS/C ACQ/PEA 52X0.2 MIRROR 1 25.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC2363-V1 STIS/N ACCUM 52X0.2 G230L 2376 1 40 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC2363-V1 STIS/N ACCUM 52X0.2 G230L 2376 1 50 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC2363-V1 STIS/F ACCUM 52X0.2 G140L 1425 3 50 M UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9339( 4) - 02/20/02 10:15 - [ 7] Summary Form for Proposal 9339 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.2 0.3X0.09 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/NUV-MAMA STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT CR-SPLIT=3 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GROUP 01-02 WITHIN 20 D PATTERN 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G750L G430L G750M G430M G230L G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC2363-OFFSET NGC2363-V1 CCDFLAT ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 7751 4300 6768 4451 2376 1425 ------------------------------------------------------------------------------------------------------------------------------------