! File: 4468C.PROP ! Database: PEPDB ! Date: 22-FEB-1994:13:17:50 coverpage: title_1: ULTRAVIOLET SPECTROPOLARIMETRY OF AG CAR IN ITS CURRENT OUTBURST title_2: CYCLE3 -- MEDIUM sci_cat: HOT STARS sci_subcat: MASSIVE STARS proposal_for: GO cont_id: 3663 pi_title: DR. pi_fname: CLAUS pi_lname: LEITHERER pi_inst: STSCI pi_country: USA pi_phone: (410) 338-4425 keywords_1: LBV'S, MASS LOSS, MASSIVE STARS, JETS hours_pri: 4.45 num_pri: 2 fos: Y time_crit: Y ! end of coverpage abstract: line_1: We propose to obtain high-resolution (R=1000) spectropolarimetry of the line_2: Luminous Blue Variable AG Carinae with the FOS. AG Car undergoes quasi- line_3: periodic outbursts on a time-scale of about 15 years. The on-set of such line_4: an outburst has recently been detected. During the outburst, the stellar line_5: mass-loss rate increases by a factor of 100, leading to the ejection of line_6: discrete shells. The relicts of previous (10e4 yr ago) mass ejections line_7: are visible as a bipolar jet and other nebulous filaments within 30" line_8: around AG Car. It is intended to measure the linear polarization of line_9: strong ultraviolet resonance lines originating in the wind of AG Car, line_10: such as Fe II (1) and Mg II (1) in the wavelength region 2300A - 3100A. line_11: Such SCATTERING lines are the most sensitive probe to study asymmetries line_12: in the wind by spectropolarimetric techniques. The scientific goal is to line_13: search for evidence for asymmetry in the stellar wind of AG Car within line_14: 10 stellar radii and to correlate the derived geometry with the line_15: morphology of the bipolar, spatially resolved structures at a distance line_16: of 0.1 pc from the star. The results will be interpreted in terms of the line_17: outburst mechanism of AG Car, and of Luminous Blue Variables in general. line_18: We request a total of 2 sets of observations, separated in time by the line_19: flow-time scale of AG Car (6 months), in order to study the temporal line_20: evolution of the flow geometry. ! ! end of abstract general_form_proposers: lname: LEITHERER fname: CLAUS title: DR. inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA esa: Y ! lname: ALTNER fname: BRUCE title: DR. inst: APPLIED RESEARCH CORPORATION country: USA ! lname: DAMINELI NETO fname: AUGUSTO title: DR. inst: UNIVERSITY OF SAO PAULO country: BRAZIL ! lname: DRISSEN fname: LAURENT title: DR. inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA ! lname: LUPIE fname: OLIVIA title: DR. mi: L. inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA ! lname: NOTA fname: ANTONELLA title: DR. inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA esa: Y ! lname: ROBERT fname: CARMELLE title: DR. inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA ! lname: SCHMUTZ fname: WERNER title: DR. inst: ETH ZUERICH country: SWITZERLAND esa: Y ! lname: SHORE fname: STEVE title: DR. mi: N. inst: GODDARD SPACE FLIGHT CENTER country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: Target Acquisition Scenario: a four stage peak-up into the 0.5" aperture line_2: for AG CAR: line_3: 4.3 aperture, a single line 3 point scan in the Y direction; line_4: 1.0 aperture, 2x6 scan to center in the X direction, step-size 0.7"; line_5: 0.5 aperture, 3x3 centered,stepsize 0.35"; line_6: 0.3 aperture, 3x3 centered, stepsize 0.2". line_7: For BD+64 (POL Standard) - 3 stage peakup into the 4.3": line_8: 4.3 aperture, a single line 3 point scan in the Y direction; line_9: 1.0 aperture, 2x6 scan to center in the X direction, step-size 0.7"; line_10: 0.5 aperture, 3x3 centered,stepsize 0.35" . line_11: Observations: line_12: Multiple visits, 1800 seconds per POL series. An exposure time of line_13: 225 seconds per spectrum (225x8 waveplate positions) yields between line_14: 31,500 and 43,500 counts/diode (peak counts in spectra) depending on line_15: the brightness and stellar type of AG CAR as it traverses it's phases. ! question: 4 section: 1 line_1: The best way to detect asymmetries in the outflow of AG Car is by line_2: measuring the polarization of scattering lines formed in the wind. line_3: In AG Car, strong scattering occurs only in resonance transitions of line_4: ions like Fe+, Mg+, and others of comparable ionization potential. All line_5: these transitions are situated in the ultraviolet below 3000 A. line_6: Therefore such observations can not be obtained from the ground. line_7: Currently HST is the only space-borne instrument capable of doing line_8: ultraviolet spectropolarimetry. ! question: 5 section: 1 line_1: The exposure time has been calculated with the FOS instrument simulator. line_2: Although AG Car will continue to brighten in the visual during the next line_3: months, the flux at 2500 A will remain nearly constant. The reason is line_4: the flux redistribution from the spectral region around the Lyman line_5: edge to the Paschen continuum, which accounts for the increase in V. line_6: The flux at the maximum of the energy distribution at about 2500 A, line_7: however, is largely unaffected when AG Car varies from early B to late line_8: B. We computed the expected energy distribution in the ultraviolet for line_9: a given V magnitude and the corresponding spectral type, with the total line_10: bolometric luminosity being constant. line_11: V magnitude/Spectral Type:7.75/B0.5Ia,7.50/B0.7Ia,7.25/B1Ia, line_12: 7.00/B2Ia,6.75/B3Ia,6.50/B5Ia,6.25/B8Ia,6.00/A0Ia. (E(B-V) = 0.63). line_14: Note that the star is well below the B/O limit for the FOS --- both line_15: with respect to the integrated rate as well to the count rate per line_16: diode --- due to the strong reddening. We find an integration time of line_17: 1800 sec per polscan in order to reach an error of 0.5% based on photon line_18: statistics. 4 sequences are required for an accuracy of 0.2% so that line_19: the total integration time comes to 7200 sec per set of observations. line_20: The standard star will be measured for 800 sec per visit. ! question: 6 section: 1 line_1: Since we intend to study the evolution of asymmetries line_2: during the outburst, it is essential to obtain the first set of line_3: observations as soon as permitted by scheduling constraints. We line_4: expect to gain insight into the ejection mechanism close to the line_5: stellar photosphere by the earlier observations. Observations line_6: performed later in the outburst will sample wind regions further line_7: downstream in the flow due to the increasing mass-loss rate and optical line_8: depth in the wind. Therefore we request that the first visit be line_9: scheduled in early 1993, and the last at the end of Cycle 3. We line_10: assumed that Cycle 3 will approximately end in December 1993 and line_11: chose the window for the REPEAT accordingly. If Cycle 3 ends line_12: later, then the last visit could also be moved to a later time. ! question: 7 section: 1 line_1: The data will be reduced and analysed at STScI as soon as they become line_2: available. The observational aspects will be addressed by L. Drissen, line_3: O. Lupie, A. Nota, F. Paresce, and C. Robert, who are experts in the line_4: field of polarization. line_5: Theoretical modeling will be done by C. Leitherer and W. Schmutz. ! question: 8 section: 1 line_1: The HST observations are supported by ground-based observations line_2: at the Brazilian National Observatory. line_3: The 1.6m telescope will be used with a Cassegrain spectrograph + line_4: CCD detector. In addition, IUE high-dispersion data will be taken line_5: during the same epoch. ! !end of general form text general_form_address: lname: LEITHERER fname: CLAUS title: DR. category: PI inst: STSCI addr_1: 3700 SAN MARTIN DRIVE city: BALTIMORE state: MD zip: 21218 country: USA phone: (410) 338-4425 telex: 684-9101-STSCI ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: HD94910 name_2: AG-CARINAE descr_1: A,148,159,905,917,926 pos_1: RA=10H 56M 11.54S +/- 0.05S, pos_2: DEC=-60D 27' 13.0" +/-0.4" equinox: 2000 pos_epoch_bj: J pos_epoch_yr: 1987.10 fluxnum_1: 1 fluxval_1: V=6.9 +/- 0.5, TYPE=B2I, E(B-V)=0.63 ! targnum: 2 name_1: BD+64D106 descr_1: J,706 pos_1: RA=00H 57M 36.71S +/- 0.03S, pos_2: DEC=+64D 51' 35.1" +/-0.2" equinox: 2000 pos_epoch_bj: J pos_epoch_yr: 1983.90 comment_1: POLARIZATION STANDARD fluxnum_1: 1 fluxval_1: V=10.4 +/- 0.2 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 10.000 targname: HD94910 config: FOS/BL opmode: ACQ/PEAK aperture: 4.3 sp_element: G190H num_exp: 1 time_per_exp: 0.2S s_to_n: 20 fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 12; req_2: SEQ 10-74 NO GAP; req_3: SPATIAL SCAN; req_4: CYCLE 3/10-74; comment_1: COARSE PEAK-UP IN 4.3. ! linenum: 12.000 targname: HD94910 config: FOS/BL opmode: ACQ/PEAK aperture: 1.0 sp_element: G190H num_exp: 1 time_per_exp: 0.6S s_to_n: 20 fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 14; req_2: SPATIAL SCAN; comment_1: COARSE PEAK-UP IN 1.0 ! linenum: 14.000 targname: HD94910 config: FOS/BL opmode: ACQ/PEAK aperture: 0.5 sp_element: G190H num_exp: 1 time_per_exp: 1.0S s_to_n: 20 fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE-X=3, param_2: SCAN-STEP-X=0.35, param_3: SEARCH-SIZE-Y=3, param_4: SCAN-STEP-Y=0.35 req_1: ONBOARD ACQ FOR 16; comment_1: FINE PEAK-UP IN 0.5 ! linenum: 16.000 targname: HD94910 config: FOS/BL opmode: ACQ/PEAK aperture: 0.3 sp_element: G190H num_exp: 1 time_per_exp: 1.0S s_to_n: 20 fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE-X=3, param_2: SCAN-STEP-X=0.2, param_3: SEARCH-SIZE-Y=3, param_4: SCAN-STEP-Y=0.2 req_1: ONBOARD ACQ FOR 21-51; comment_1: PRECISE PEAK-UP IN 0.3. ! linenum: 21.000 targname: HD94910 config: FOS/BL opmode: ACCUM aperture: 0.5 sp_element: G270H num_exp: 1 time_per_exp: 1800S s_to_n: 300 fluxnum_1: 1 priority: 1 param_1: POLSCAN=8B ! linenum: 31.000 targname: HD94910 config: FOS/BL opmode: ACCUM aperture: 0.5 sp_element: G270H num_exp: 1 time_per_exp: 1800S s_to_n: 300 fluxnum_1: 1 priority: 1 param_1: POLSCAN=8B ! linenum: 41.000 targname: HD94910 config: FOS/BL opmode: ACCUM aperture: 0.5 sp_element: G270H num_exp: 1 time_per_exp: 1800S s_to_n: 300 fluxnum_1: 1 priority: 1 param_1: POLSCAN=8B ! linenum: 51.000 targname: HD94910 config: FOS/BL opmode: ACCUM aperture: 0.5 sp_element: G270H num_exp: 1 time_per_exp: 1800S s_to_n: 300 fluxnum_1: 1 priority: 1 param_1: POLSCAN=8B ! linenum: 70.000 targname: BD+64D106 config: FOS/BL opmode: ACQ/PEAK aperture: 4.3 sp_element: G570H num_exp: 1 time_per_exp: 1.0S s_to_n: 10 fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 71; req_2: SPATIAL SCAN comment_1: COARSE PEAKUP IN 4.3 ! linenum: 71.000 targname: BD+64D106 config: FOS/BL opmode: ACQ/PEAK aperture: 1.0 sp_element: G570H num_exp: 1 time_per_exp: 2.0S s_to_n: 10 fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 72; req_2: SPATIAL SCAN; comment_1: COARSE PEAKUP IN 1.0 ! linenum: 72.000 targname: BD+64D106 config: FOS/BL opmode: ACQ/PEAK aperture: 0.5 sp_element: G570H num_exp: 1 time_per_exp: 4.0S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE-X=3, param_2: SCAN-STEP-X=0.35, param_3: SEARCH-SIZE-Y=3, param_4: SCAN-STEP-Y=0.35 req_1: ONBOARD ACQ FOR 74; comment_1: FINE PEAK-UP IN 0.5 ! linenum: 74.000 targname: BD+64D106 config: FOS/BL opmode: ACCUM aperture: 4.3 sp_element: G270H num_exp: 1 time_per_exp: 800S s_to_n: 100 fluxnum_1: 1 priority: 1 param_1: POLSCAN=8B req_1: REPEAT 10-74 EVERY 200D +/- 100D req_2: FOR 1 MORE TIMES comment_3: HIGH POLARIZATION STANDARD TARGET. ! ! end of exposure logsheet scan_data: line_list: 10 fgs_scan: N cont_dwell: D dwell_pnts: 3 dwell_secs: 1.00 scan_width: 0.0000 scan_length: 2.8000 sides_angle: 90.0000 number_lines: 1 scan_rate: 0.0000 first_line_pa: 0.0000 scan_frame: S/C len_offset: 1.400 wid_offset: 0.0 ! line_list: 12 fgs_scan: N cont_dwell: D dwell_pnts: 6 dwell_secs: 0.30 scan_width: 0.7000 scan_length: 3.5000 sides_angle: 90.0000 number_lines: 2 scan_rate: 0.0000 first_line_pa: 90.0000 scan_frame: S/C len_offset: 1.75 wid_offset: 0.35 ! line_list: 70 fgs_scan: N cont_dwell: D dwell_pnts: 3 dwell_secs: 1.00 scan_width: 0.0000 scan_length: 2.8000 sides_angle: 90.0000 number_lines: 1 scan_rate: 0.0000 first_line_pa: 0.0000 scan_frame: S/C len_offset: 1.400 wid_offset: 0.0 ! line_list: 71 fgs_scan: N cont_dwell: D dwell_pnts: 6 dwell_secs: 2.00 scan_width: 0.7000 scan_length: 3.5000 sides_angle: 90.0000 number_lines: 2 scan_rate: 0.0000 first_line_pa: 90.0000 scan_frame: S/C len_offset: 1.75 wid_offset: 0.35 ! ! end of scan data