8403( 3) - 06/24/99 07:09 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8403 Version: 3 Check-in Date: 24-Jun-1999 07:08:43 1.Proposal Title: NGC 2363 V1: a rare case of major LBV eruption ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Laurent Drissen Universite Laval CoI: Jean-Rene Roy Universite Laval N CoI: Carmelle Robert Universite Laval N CoI: Paul Crowther University College London N CoI: Linda Smith University College London N ------------------------------------------------------------------------------------ 5. Abstract In 1996 January, HST/WFPC2 images revealed the presence of a new bright, blue star in the extragalactic giant H II region NGC 2363. We have shown that this star is a Luminous Blue variable (LBV) undergoing a major outburst. Only a handful of major LBV eruptions have been observed, including those of P Cygni in the 17^th century and Eta Carina between 1840 and 1860. We therefore propose to follow in detail the spectrophotometric evolution of NGC2363-V1 until the end of its major eruption. STIS observations in Cycle 7 yielded crucial information on the star's mass loss rate, temperature, luminosity and chemical composition. Cycle 8 observations will monitor variations of these parameters with time. ------------------------------------------------------------------------------------ 8403( 3) - 06/24/99 07:09 - [ 2] Observations Description ------------------------ 1 - Imagery The WFPC2 observations are relatively simple. We want to determine the flux distribution from the UV to the near IR with an accuracy better than 10percent. The following exposure times were determined assuming that V1 is a B0 supergiant of magnitude V=18 (which was its status as of 1997 February, when we got the latest images with the CFHT). A S/N ratio of 50 is needed; this will assure us that if the star dims to its pre-outburst stage (V~ 21), it will still be visible on all images. We used the WFPC2 ETC on the WWW to obtain the following: F170W: 1000s; F336W, 60s; F547M, 10s; F1042M, 700s; the F547M and F336W exposure times were increased to 60S and 100S, respectively, to fill the orbit. The F170W and F1042M observations will be made with CR-split (default for exposures longer than 600S). Adding the GSAcq and the CCD readout time, one orbit is required for each series. The STIS observations will be done at the beginning of the cycle, and the two WFPC2 series will be spread over the rest of the cycle. 2 - Spectroscopy The acquisition will proceed 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' 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. Using the STIS ETC on the WWW, and assuming a B0I spectrum, 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. The times have been ajusted to fill the orbits efficiently. The STIS/CCD and STIS/MAMA observations were split into two visits, separated by less than 20 days in order to follow the new guidelines. One series of spectra for each of cycles 7, 8 and 9 will be obtained to monitor the long-term evolution of the star. Real Time Justification ----------------------- We would like to have the series of images separated as evenly in time as possible, and the STIS spectra taken as early as possible in Cycle 8, while the star is still in its outburst phase. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Paper Products: Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8403( 3) - 06/24/99 07:09 - [ 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 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 stable 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 8403( 3) - 06/24/99 07:09 - [ 4] Visit: 01 Visit Priority: Visit Requirements: GROUP 1-2 WITHIN 20 D BEFORE 01-Dec-1999 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. In 1998, our Cycle 7 HST images and spectra showed that NGC2363-V1 is still in it outburst phase. But we have no idea how long the outburst will last. Therefore, we request that the STIS observations be made as early as possible during cycle 8. 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 ONBOARD ACQ FOR 20 SET CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC2363-V1 STIS/C ACQ/PEA 52X0.2 MIRROR 1 25.0 S ONBOARD ACQ FOR 30 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 45 M CD ------------------------------------------------------------------------------------------------------------------------------------ 50 NGC2363-V1 STIS/C ACCUM 52X0.2 G750M 6768 CR-SPLIT=3 1 45 M CD ------------------------------------------------------------------------------------------------------------------------------------ 8403( 3) - 06/24/99 07:09 - [ 5] Visit: 02 Visit Priority: Visit Requirements: GROUP 1-2 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 ONBOARD ACQ FOR 2 SET CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC2363-V1 STIS/C ACQ/PEA 52X0.2 MIRROR 1 25.0 S ONBOARD ACQ FOR 3 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 ------------------------------------------------------------------------------------------------------------------------------------ 8403( 3) - 06/24/99 07:09 - [ 6] Visit: 03 Visit Priority: Visit Requirements: AFTER 02 BY 100 D TO 150 D 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC2363-V1 WFPC2 IMAGE PC1-FIX F170W 1 800 S ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC2363-V1 WFPC2 IMAGE PC1-FIX F1042M 1 800 S ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC2363-V1 WFPC2 IMAGE PC1-FIX F547M 1 100 S ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC2363-V1 WFPC2 IMAGE PC1-FIX F336W 1 100 S ------------------------------------------------------------------------------------------------------------------------------------ 8403( 3) - 06/24/99 07:09 - [ 7] Visit: 04 Visit Priority: Visit Requirements: AFTER 03 BY 100 D TO 150 D 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC2363-V1 WFPC2 IMAGE PC1-FIX F170W 1 800 S ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC2363-V1 WFPC2 IMAGE PC1-FIX F1042M 1 800 S ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC2363-V1 WFPC2 IMAGE PC1-FIX F547M 1 100 S ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC2363-V1 WFPC2 IMAGE PC1-FIX F336W 1 100 S ------------------------------------------------------------------------------------------------------------------------------------ 8403( 3) - 06/24/99 07:09 - [ 8] Summary Form for Proposal 8403 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.2 0.3X0.09 PC1-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/NUV-MAMA STIS/FUV-MAMA WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT CR-SPLIT=3 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GROUP 1-2 WITHIN 20 D BEFORE 01-Dec-1999 ONBOARD ACQ FOR 20 ONBOARD ACQ FOR 30 GROUP 1-2 WITHIN 20 D ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 3 AFTER 02 BY 100 D TO 150 D AFTER 03 BY 100 D TO 150 D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G750L G430L G750M G230L G140L F170W F1042M F547M F336W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC2363-OFFSET NGC2363-V1 CCDFLAT ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 7751 4300 6768 2376 1425 ------------------------------------------------------------------------------------------------------------------------------------