! $Id: 29,v 4.1 1994/07/26 20:56:29 pepsa Exp $ coverpage: title_1: ULTRAVIOLET SPECTROPOLARIMETRY OF AA AND IN ITS CURRENT ACTIVITY sci_cat: STELLAR ASTROPHYSICS sci_subcat: MASSIVE STARS proposal_for: GO/DD pi_title: DR. pi_fname: JOE pi_lname: ASTRONOMER pi_inst: STSCI pi_country: USA pi_phone: (301) 338-4700 keywords_1: MASS LOSS, MASSIVE STARS hours_pri: 1.11 num_pri: 2 fos: Y time_crit: Y pi_position: ASTRONOMER ! end of coverpage abstract: line_1: We propose to obtain high-resolution (R=1000) line_2: spectropolarimetry of the O-type variable AA And with the line_3: FOS. AA And undergoes quasi-periodic outbursts on a line_4: time-scale of about 45 years. The on-set of such an outburst line_5: has recently been detected. During the outburst, the stellar line_6: mass-loss rate increases by a factor of 2, leading to the line_7: ejection of discrete shells. It is intended to measure the line_8: linear polarization of strong ultraviolet resonance lines line_9: originating in the wind of AA And, such as line_10: 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 line_12: asymmetries in the wind by spectropolarimetric techniques. line_13: The scientific goal is to search for evidence for asymmetry line_14: in the stellar wind of AA And within 10 stellar radii. line_15: The results will be interpreted in terms of the outburst line_16: mechanism of AA Andr, and of O stars in general. ! ! end of abstract general_form_proposers: lname: ASTRONOMER fname: JOE title: DR. inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA esa: N ! ! 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 line_2: 0.5" aperture for AA AND: 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, line_5: step-size 0.7"; line_6: 0.5 aperture, 3x3 centered,stepsize 0.35"; line_7: 0.3 aperture, 3x3 centered, stepsize 0.2". line_8: For BD+55 (POL Standard) - three stage peakup into the 4.3": line_9: 4.3 aperture, a single line 3 point scan in the Y direction; line_10: 1.0 aperture, 2x6 scan to center in the X direction, line_11: step-size 0.7"; line_12: 0.5 aperture, 3x3 centered,stepsize 0.35" . line_13: Observations: line_14: Multiple visits, 800 seconds per POL series. An exposure time line_15: of 100 seconds per spectrum (100x8 waveplate positions) line_16: yields between 31,500 and 43,500 counts/diode (peak counts in line_17: spectra) depending on the brightness and stellar type of AA line_18: AND as it traverses it's phases. ! question: 4 section: 1 line_1: The best way to detect asymmetries in the outflow of AA And line_2: is by measuring the polarization of scattering lines formed line_3: in the wind. In AA And, strong scattering occurs only in line_4: resonance transitions of ions like Fe+, Mg+, and others of line_5: comparable ionization potential. All these transitions are line_6: situated in the ultraviolet below 3000 A. Therefore such line_7: observations can not be obtained from the ground. Currently line_8: HST is the only space-borne instrument capable of doing line_9: ultraviolet spectropolarimetry. ! question: 5 section: 1 line_1: The exposure time has been calculated with the FOS instrument line_2: simulator. Although AA And will continue to brighten in the line_3: visual during the next months, the flux at 2500 A will remain line_4: nearly constant. The reason is the flux redistribution from line_5: the region around the Lyman edge to the Paschen continuum, line_6: which accounts for the increase in V. The flux at the line_7: maximum of the energy distribution at about 2500 A, however, line_8: is largely unaffected when AA And varies from early B to late line_9: B. We computed the expected energy distribution in the line_10: ultraviolet for a given V magnitude and the corresponding line_11: spectral type, with the total bolometric luminosity being line_12: constant. V magnitude/Spectral Type:7.75/B0.5Ia,7.50/B0.7Ia, line_13: 7.25/B1Ia,7.00/B2Ia,6.75/B3Ia,6.50/B5Ia,6.25/B8Ia,6.00/A0Ia. line_14: (E(B-V) = 0.63). line_16: Note that the star is well below the B/O limit for the FOS - line_17: both with respect to the integrated rate as well to the count line_18: rate per diode - due to the strong reddening. We find an line_19: integration time of 800 sec per polscan in order to reach an line_20: error of 0.7% based on photon statistics. 4 sequences are line_21: required for an accuracy of 0.3% so that the total line_22: integration time comes to 3200 sec per set of observations. line_23: 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 during line_2: the outburst, it is essential to obtain the first set of line_3: observations as soon as permitted by scheduling constraints. line_4: We expect to gain insight into the ejection mechanism close line_5: to the stellar photosphere by the observations. Observations line_6: performed later in the outburst will sample wind regions line_7: further downstream in the flow due to the increasing line_8: mass-loss rate and optical depth in the wind. Therefore we line_9: request the first observations to be scheduled in line_10: JUNE/JULY 1991. ! question: 7 section: 1 line_1: The data will be reduced and analysed at STScI as soon as line_2: they become available. ! question: 8 section: 1 line_1: The HST observations are supported by ground-based line_2: observations at the Kitt Peak National Observatory. ! question: 9 section: 1 line_1: A description of any previous HST data goes here. ! question: 10 section: 1 line_1: Resources provided by your home institution goes here. ! !end of general form text general_form_address: lname: ASTRONOMER fname: JOE title: DR. category: PI inst: STSCI addr_1: 3700 SAN MARTIN DRIVE city: BALTIMORE state: MD zip: 21218 country: USA phone: (301) 338-4700 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: AA-ANDROMEDAE name_2: HD99111 descr_1: A,105,148 pos_1: PLATE-ID=0TT5, pos_2: RA=01H 22M 17.55S +/- 0.05S, pos_3: DEC=+55D 47' 17.0" +/-0.4" equinox: 2000 fluxnum_1: 1 fluxval_1: V=8.3 +/- 0.5, TYPE=O4I, E(B-V)=0.33 ! targnum: 2 name_1: BD+55D101 descr_1: A,111 pos_1: PLATE-ID=7TY9, pos_2: RA=05H 27M 19.71S +/- 0.03S, pos_3: DEC=+55D 11' 45.1" +/-0.2" equinox: 2000 comment_1: POLARIZATION STANDARD fluxnum_1: 1 fluxval_1: V=11.4 +/- 0.2 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 10.000 targname: AA-ANDROMEDAE config: FOS/BL opmode: ACQ/PEAK aperture: 4.3 sp_element: G270H num_exp: 1 time_per_exp: 0.1S 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 1/10-74; comment_1: COARSE PEAK-UP IN 4.3. ! linenum: 12.000 targname: AA-ANDROMEDAE config: FOS/BL opmode: ACQ/PEAK aperture: 1.0 sp_element: G270H num_exp: 1 time_per_exp: 0.3S s_to_n: 20 fluxnum_1: 1 priority: 1 req_1: ONBOARD ACQ FOR 14; req_2: SPATIAL SCAN; req_3: CYCLE 1 / 12-74; comment_1: COARSE PEAK-UP IN 1.0 ! linenum: 14.000 targname: AA-ANDROMEDAE config: FOS/BL opmode: ACQ/PEAK aperture: 0.5 sp_element: G270H num_exp: 1 time_per_exp: 0.5S s_to_n: 20 fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE=3, param_2: SCAN-STEP=0.35 req_1: ONBOARD ACQ FOR 16; comment_1: FINE PEAK-UP IN 0.5 ! linenum: 16.000 targname: AA-ANDROMEDAE config: FOS/BL opmode: ACQ/PEAK aperture: 0.3 sp_element: G270H num_exp: 1 time_per_exp: 0.5S s_to_n: 20 fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE=3, param_2: SCAN-STEP=0.2 req_1: ONBOARD ACQ FOR 21-51; comment_1: PRECISE PEAK-UP IN 0.3. ! linenum: 21.000 targname: AA-ANDROMEDAE config: FOS/BL opmode: ACCUM aperture: 0.5 sp_element: G270H num_exp: 1 time_per_exp: 800S s_to_n: 300 fluxnum_1: 1 priority: 1 param_1: POLSCAN=8B ! linenum: 31.000 targname: AA-ANDROMEDAE config: FOS/BL opmode: ACCUM aperture: 0.5 sp_element: G270H num_exp: 1 time_per_exp: 800S s_to_n: 300 fluxnum_1: 1 priority: 1 param_1: POLSCAN=8B ! linenum: 41.000 targname: AA-ANDROMEDAE config: FOS/BL opmode: ACCUM aperture: 0.5 sp_element: G270H num_exp: 1 time_per_exp: 800S s_to_n: 300 fluxnum_1: 1 priority: 1 param_1: POLSCAN=8B ! linenum: 51.000 targname: AA-ANDROMEDAE config: FOS/BL opmode: ACCUM aperture: 0.5 sp_element: G270H num_exp: 1 time_per_exp: 800S s_to_n: 300 fluxnum_1: 1 priority: 1 param_1: POLSCAN=8B ! linenum: 70.000 targname: BD+55D101 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+55D101 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+55D101 config: FOS/BL opmode: ACQ/PEAK aperture: 0.5 sp_element: G570H num_exp: 1 time_per_exp: 2.0S s_to_n: 10 fluxnum_1: 1 priority: 1 param_1: SEARCH-SIZE=3, param_2: SCAN-STEP=0.35 req_1: ONBOARD ACQ FOR 74; comment_1: FINE PEAK-UP IN 0.5 ! linenum: 74.000 targname: BD+55D101 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 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: 0.10 scan_width: 0.0000 scan_length: 2.8660 sides_angle: 0.0000 number_lines: 1 scan_rate: 0.0000 first_line_pa: 0.0000 scan_frame: S/C len_offset: 1.433 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: 2.8660 sides_angle: 0.0000 number_lines: 1 scan_rate: 0.0000 first_line_pa: 0.0000 scan_frame: S/C len_offset: 1.433 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