8300( 5) - 09/15/00 10:37 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8300 Version: 5 Check-in Date: 15-Sep-2000 10:36:38 1.Proposal Title: Testing the Falling Evaporating Bodies hypothesis on the Herbig star HD100546 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Anne-Marie Lagrange Groupe d'Astrophysique de Grenoble CoI: Dr Herve Beust Observatoire de Grenoble N CoI: Mr Jean-Charles Augereau Observatoire de Grenoble N CoI: Dr David Mouillet Observatoire de Grenoble N ------------------------------------------------------------------------------------ 5. Abstract It has been recently proposed that several Herbig stars exhibit spectroscopic variable features similar to those of the older, Main Sequence star, beta Pictoris, and by analogy attributed to evaporation of cometary-like bodies falling on to the star. The presence of such around Herbig stars is an important issue regarding the evolutionary timescales of planetary systems formation. However, this hypothesis is still controversial and needs to be tested. The only way to do so is to compare the observations with detailed, dedicated simulations, as we successfully did on beta Pictoris. This is also the only way to reliably estimate the physical (sizes, evaporation rates, etc) and orbital parameters of the suspected infalling bodies. We recently adopted this approach in one of the sofar most convincing cases of Herbig candidates for cometary infalls, namely HD100546, comparing IUE data with the predictions of our model. First tests could be done, eventhough limited, due to the lim it ed Signal/Noise provided by IUE and to the limited number of available data. Important differences have already been found between this object and beta Pictoris. We propose to record STIS data to test the cometary hypothesis for this star into more details and more quantitatively, from both dynamical and chemical points of view. ------------------------------------------------------------------------------------ 8300( 5) - 09/15/00 10:37 - [ 2] Observations Description ------------------------ We propose to make two visits on the star. First visit will consist of a full coverage of the spectrum, so as to make a complete analysis of the variable lines and to properly compute the radiation pressure (RP). The full coverage is expected to take 4 orbits (see below). In order to monitor short term variations, we will record a spectrum in the MgII at each orbit. The second visit will aim at studying the longer term variability of the strongest or most interesting features : CIV, AlIII, SiII, AlII, SiII, ZnII, FeII and MgII. Note that the optical survey shows variable lines at almost any time so we feel confident that variable lines will be present during the HST observations as well. Also, and very importantly, even a rather quiet spectra would enable to study the stable gas around this star, as done in beta Pictoris (Lagrange et al 1998a). Real Time Justification ----------------------- The spectral ranges will be scanned with the prime settings of Ech 230H and Ech 140H given in the STIS Instrument Handbook. The following table gives for each scan setting the observing time required to achieve a Signal-to-Noise of about 30, assuming either a flat continuum scaled to the flux on the IUE data or, for the 1234 Angstrom (A) wavelength setting, B8V spectrum scaled to the V magnitude, and that both sky background and the detector dark current are negligible. These values have been computed using the ETC.--------------------- ------------------------------------------------------------------------------- -------------- | Central Wavelength (A) | S/N | Exp. Time (s) | Lines---------- ------------------------------------------------------------------------------- ------------------------- | 1234 32 2350 NV, SiIII, SiIV, PI, PII, PIII, TiIII, SIII etc | 1416 30 5 00 SiIV, OIV, SIV, etc | 1598 29 985 NIV, CIV, CI, SiII, FeII, CO, etc | 1763 28 985 AlII, AlIII, CI, FeII, MgI, SiII, SI, etc | 2013 30 520 NiII, TiII, CIII ?, CrII, ZnII, etc | 2263 30 410 FeII (ground), AlI, MnI | 2513 30 310 FeI, AlI, MnII, FeII, FeII*, etc | 2762 30 310 MgII, MgI, FeII (MS), etc |-------------------------------------------------------------------- ----------------------------------------- Taking into account the visibility period of the star (58') and the various overheads described in STIS Instrument Handboo k, we need 6 orbits to perform the programm: visit 1 / orbit 1: 2762, 2513 and 2263 A visit 1 / orbit 2: 2762, 1763 and 1598 A visit 1 / orbit 3: 2762 and 1234 A visit 1 / orbit 4: 2762, 2013 and 1416 A visit 2 / orbit 1: 2762, 2513 and 2013 A visit 2 / orbit 2: 2762, 1763 and 1598 A So as to investigate the long term variability of the strongest or most interesting features, we request for a delay of at least 7 days between visit 1 and visit 2. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 8300( 5) - 09/15/00 10:37 - [ 3] Data Distribution Paper Products: YES Media: DAT Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8300( 5) - 09/15/00 10:37 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD100546 STAR, B6-B9.5 V-IV, RA=11H 33M 25.44S +/- 0.5", DEC= J2000 V = 6.8 EMISSION LINE STAR -70D 11' 41.2" +/- 0.5" TYPE=B9V B-V = 0.1 F(1416)=22+/-2e-12 F(1598)=20+/-2e-12 F(2513)=8+/-2e-12 F(2263)=8+/-2e-12 F(1763)=17+/-2e-12 F(2013)=12+/-3e-12 Coordinate Source: Comments: Coordinates from Hipparcos. V magnitude and Color F(2762)=8+/-1e-12 Index from the Simbad database. Flux from the IUE database. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J2000 -0.00763 -0.00005 0.00967 8300( 5) - 09/15/00 10:37 - [ 5] Visit: 01 Visit Priority: 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 HD100546 STIS/C ACQ F28X50O MIRROR ACQTYPE=POINT 1 0.2 S CD II Comments: ETC ID = 22081 for an A1V star , S/N = 98.5 ;;; ETC ID = 22086 for a B8V star , S/N = 99.5 ------------------------------------------------------------------------------------------------------------------------------------ 2 HD100546 STIS/C ACQ/PEA 0.2X0.0 G430M 4194 1 0.1 S CD K 5ND Comments: ETC ID = 22322 for an A1V star : counts = 12890 ;;; ETC ID = 22317 for a B8V star : counts = 13220 ------------------------------------------------------------------------------------------------------------------------------------ 10 HD100546 STIS/N ACCUM 0.2X0.0 E230H 2762 1 310 S UV-MAM 9 A Comments: ETC ID = 28336, Peak local count rate was 0.4833 counts/sec/pix at 2647 Angstrom, Global count rate = 5.091e+04 counts/sec ------------------------------------------------------------------------------------------------------------------------------------ 11 HD100546 STIS/N ACCUM 0.2X0.0 E230H 2513 1 310 S UV-MAM 9 A Comments: ETC ID = 28305, Peak local count rate was 0.4822 counts/sec/pix at 2647 Angstrom, Global count rate = 5.792e+04 counts/sec ------------------------------------------------------------------------------------------------------------------------------------ 12 HD100546 STIS/N ACCUM 0.2X0.0 E230H 2263 1 410 S UV-MAM 9 A Comments: ETC ID = 28265, Peak local count rate was 0.447 counts/sec/pix at 2401.5 Angstrom, Global count rate = 4.991e+04 counts/sec ------------------------------------------------------------------------------------------------------------------------------------ 20 HD100546 STIS/N ACCUM 0.2X0.0 E230H 2762 1 310 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 21 HD100546 STIS/N ACCUM 0.2X0.0 E230H 1763 1 985 S UV-MAM 9 A Comments: ETC ID = 26314, Peak local count rate was 0.2798 counts/sec/pix at 1901.5 Angstrom, Global count rate = 2.684e+04 counts/sec ------------------------------------------------------------------------------------------------------------------------------------ 8300( 5) - 09/15/00 10:37 - [ 6] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 22 HD100546 STIS/F ACCUM 0.2X0.0 E140H 1598 1 985 S UV-MAM 9 A Comments: ETC ID = 28326, Peak local count rate was 0.1412 counts/sec/pix at 1497 Angstrom, Global count rate = 1.677e+04 counts/sec ------------------------------------------------------------------------------------------------------------------------------------ 30 HD100546 STIS/N ACCUM 0.2X0.0 E230H 2762 1 310 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 31 HD100546 STIS/F ACCUM 0.2X0.0 E140H 1234 1 2350 S UV-MAM 9 A Comments: ETC ID = 26485 for a B8V star : Peak local count rate was 0.3531 counts/sec/pix at 1324.6 Angstroms , Global count rate: 3.395e+04 counts/sec ;;;; ETC ID = 26506 for an A0V STAR : Peak local count rate was 0.05302 counts/sec/pix at 1325.7 Angstroms , Global count rate: 2813 counts/sec. ------------------------------------------------------------------------------------------------------------------------------------ 40 HD100546 STIS/N ACCUM 0.2X0.0 E230H 2762 1 310 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 41 HD100546 STIS/N ACCUM 0.2X0.0 E230H 2013 1 520 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 42 HD100546 STIS/F ACCUM 0.2X0.0 E140H 1416 1 500 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 8300( 5) - 09/15/00 10:37 - [ 7] Visit: 02 Visit Priority: Visit Requirements: AFTER 01 BY 7 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 HD100546 STIS/C ACQ F28X50O MIRROR ACQTYPE=POINT 1 0.2 S CD II Comments: ETC ID = 22081 for an A1V star , S/N = 98.5 ;;; ETC ID = 22086 for a B8V star , S/N = 99.5 ------------------------------------------------------------------------------------------------------------------------------------ 2 HD100546 STIS/C ACQ/PEA 0.2X0.0 MIRROR 1 0.1 S CD K 5ND Comments: ETC ID = 22322 for an A1V star : counts = 12890 ;;; ETC ID = 22317 for a B8V star : counts = 13220 ------------------------------------------------------------------------------------------------------------------------------------ 10 HD100546 STIS/N ACCUM 0.2X0.0 E230H 2762 1 310 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 11 HD100546 STIS/N ACCUM 0.2X0.0 E230H 2513 1 310 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 12 HD100546 STIS/N ACCUM 0.2X0.0 E230H 2013 1 520 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 20 HD100546 STIS/N ACCUM 0.2X0.0 E230H 2762 1 310 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 21 HD100546 STIS/N ACCUM 0.2X0.0 E230H 1763 1 985 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 22 HD100546 STIS/F ACCUM 0.2X0.0 E140H 1598 1 985 S UV-MAM 9 A ------------------------------------------------------------------------------------------------------------------------------------ 8300( 5) - 09/15/00 10:37 - [ 8] Summary Form for Proposal 8300 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50OII 0.2X0.05ND 0.2X0.09 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/NUV-MAMA STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements AFTER 01 BY 7 D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G430M E230H E140H ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD100546 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 4194 2762 2513 2263 1763 1598 1234 2013 1416 ------------------------------------------------------------------------------------------------------------------------------------