! File: 1207C.PROP ! Database: PEPDB ! Date: 16-FEB-1994:05:59:58 coverpage: title_1: ULTRAVIOLET TOMOGRAPHY OF V471 TAURI, CYCLE 3 sci_cat: STELLAR ASTROPHYSICS sci_subcat: COOL STARS proposal_for: AUG/HRS pi_fname: FREDERICK pi_mi: M. pi_lname: WALTER pi_inst: STONY BROOK, STATE UNIVERSITY OF NEW YORK pi_country: USA pi_phone: (516)632-8232 keywords_1: TRANSITION REGIONS; STELLAR ATMOSPHERIC PROFILES; keywords_2: STELLAR TOMOGRAPHY; ECLIPSING BINARIES hours_pri: 2.50 num_pri: 1 time_crit: X pi_position: ASSISTANT PROFESSOR ! end of coverpage abstract: line_1: The V471 Tau system consists of a very active K2 dwarf which line_2: totally eclipses a hot white dwarf every 12.5 hours. We shall line_3: use the passage of the white dwarf behind the K dwarf to line_4: probe the temperature and density structure of the line_5: atmosphere with height above the surface of the K dwarf. We line_6: will use 0.5 second rapid readouts to probe the K2V line_7: atmosphere on a linear scale of about 1% of the radius of line_8: the white dwarf. Observations at ingress and egress will line_9: probe lines of sight through opposite hemispheres of the line_10: K2V atmosphere; a repeat observations after a year will line_11: reveal changes in the atmospheric structure. ! ! end of abstract general_form_proposers: lname: WALTER fname: FREDERICK mi: M. inst: SUNY, STONY BROOK country: USA ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: ! question: 3 section: 1 line_1: The pair of observations consists of an ingress observation, line_2: commencing at phase 0.935, or 25m prior to first contact, line_3: and egress observation commencing at phase 0.029, or 2m line_4: prior the third contact. If the pair cannot be obtained on line_5: one orbit (it would require 97m with a 43m gap in the middle line_6: -- earth occultation may preclude this), then the pair must line_7: be obtained on succeeding orbits (~ 12h apart). While the line_8: exposure logsheet specifies observation 1 precedes 2, line_9: observation 2 can precede 1 if the proper phases are line_10: observed at an ~ 12h interval. line_11: The timing is crucial: Exposures must begin with a line_12: tolerance of ~+/-20s. ! question: 4 section: 1 line_1: The far UV chromospheric and transition region lines are line_2: inaccessible from the ground. ! question: 5 section: 1 line_1: The continuous time resolution herein necessitates use of HRS rapid read line_2: out. No real time dumps are needed - a tape recorder dump is sufficient. line_3: Based on the IUE spectra of V471 Tau, a 10 A EW C IV absorption line line_4: (which has been observed) is detectable at 3 sigma in about 2 second using the line_5: HRS at low resolution. Two second time resolution corresponds to ~1% of the K line_6: star radius or 500 km. To achieve this spatial resolution we will require rapid line_7: readout on a 1 sec timescale. line_8: The time of zero phase given in the exposure logsheet is heliocentric. The line_9: heliocentric correction (<=+/-8m) must be applied to this time to insure proper line_10: phase coverage. The phases listed in the exposure logsheet are for the start of line_11: the observation. ! question: 6 section: 1 line_1: There are no special calibration requirements. ! question: 7 section: 1 line_1: The data will be reduced as a time ordered series of spectra, and co-added line_2: to obtain optimum S/N and time resolution. The chromospheric and transition line_3: region lines of K dwarf will go into absorption as the white dwarf transverses line_4: the K star atmosphere. Variations in the equivalent widths of the lines with line_5: time will be translated into column densities as a function of height. ! question: 8 section: 1 line_1: V471 Tau does exhibit small period changes. We shall supply an updated line_2: ephemeris, prior to scheduling. This a side 1 proposal, and line_3: is to be scheduled ONLY if side 1 is repaired during cycle 3. line_4: The spectral elements need to be changed to N1 and G140L line_5: prior to scheduling. ! question: 9 section: 1 line_1: GTO programs 1208,1210. Data are being analyzed. The line_2: preliminary analysis of the 1210 observations was presented line_3: at the 7th Cambridge Cool Stars Workshop (October 1991); line_4: premininary interpretation of the spectra from program 1208 line_5: were presented in February 1992 at the 10th International line_6: Colloquium on X-Ray and Ultraviolet Observations of line_7: Laboratory and Astrophysical Plasmas. ! question: 10 section: 1 line_1: SUNY will supply an office and electricity. We have computing line_2: capacity here, and at GSFC, for scientific analysis of these data. ! question: 13 section: 1 line_1: The passage of the hot white dwarf in the V471 system behind line_2: the K star will be used to probe the temperature and density line_3: structure of the atomsphere of an active K dwarf. The line_4: observation consists of an ingress and an egress observation line_5: to yield 2 lines of sight through the K star atmosphere ! !end of general form text general_form_address: lname: WALTER fname: FREDERICK mi: M. category: PI inst: SUNY, STONY BROOK addr_1: ESS DEPARTMENT city: STONY BROOK state: NY country: USA phone: 516-632-8232 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: BD+16D516 name_2: V471-TAURI descr_1: A,120,139 pos_1: RA=3H50M24.786S+/-0.2S, pos_2: DEC=17D14'47.85"+/-1" equinox: 2000 comment_1: POSITION FROM GSC PLATE 00FH fluxnum_1: 1 fluxval_1: V=9.40 fluxnum_2: 2 fluxval_2: B=10.32 fluxnum_3: 3 fluxval_3: F-CONT (1550) = 1.0 E-12 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: V-ACQ targname: BD+16D516 config: HRS opmode: ACQ aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 1.8S fluxnum_1: 1 fluxnum_2: 2 priority: # param_1: FAINT=100., param_2: BRIGHT=RETURN, param_3: SEARCH-SIZE=3, req_1: ONBOARD ACQ FOR 1.1; comment_1: STEP-TIME=0.2 comment_2: ****************************** comment_3: THIS IS A SIDE 1 PROPOSAL comment_4: SP_ELEMENT SHOULD BE N1 comment_5: ****************************** ! linenum: 1.100 sequence_1: DEFINE sequence_2: V-ACQ targname: BD+16D516 config: HRS opmode: ACQ/PEAKUP aperture: 2.0 sp_element: MIRROR-N2 num_exp: 1 time_per_exp: 163.2S priority: ^ comment_1: ****************************** comment_2: THIS IS A SIDE 1 PROPOSAL comment_3: SP_ELEMENT SHOULD BE N1 comment_4: ****************************** ! linenum: 2.000 sequence_1: DEFINE sequence_2: ECLIPSE targname: ^ config: HRS opmode: RAPID aperture: 2.0 sp_element: G160M wavelength: 1430 num_exp: 1 time_per_exp: 35M fluxnum_1: 3 priority: ^ param_1: SAMPLE-TIME=0.5 req_1: NON-INT /2 comment_1: ****************************** comment_2: THIS IS A SIDE 1 PROPOSAL comment_3: SP_ELEMENT SHOULD BE G140L comment_4: ****************************** ! linenum: 10.000 sequence_1: USE sequence_2: V-ACQ priority: 1 req_1: PERIOD 0.52118308D +/- 0.01S; req_2: ZERO-PHASE JD2440612.67079 +/- 25.0S; req_3: PHASE 0.5+/-0.46; req_4: CYCLE 3 / 10-10.1; req_5: ONBOARD ACQ FOR 10.1; comment_1: ZERO-PHASE WILL BE UPDATED LATER comment_2: ACQUISITION OF WHITE DWARF. comment_3: ACQUISITION WILL FAIL IF comment_4: SCHEDULED DURING WD ECLIPSE, comment_5: PHASES .969-0.031 ! linenum: 10.100 sequence_1: USE sequence_2: ECLIPSE priority: 1 req_1: PHASE 0.930+/-0.001 OF REF 10; ! linenum: 11.000 sequence_1: USE sequence_2: V-ACQ priority: 1 req_1: PHASE 0.5+/-0.46 OF REF 10; req_2: CYCLE 3 / 11-11.1; req_3: ONBOARD ACQ FOR 11.1 ! linenum: 11.100 sequence_1: USE sequence_2: ECLIPSE priority: 1 req_1: GROUP 10-11.1 WITHIN 15H; req_2: PHASE 0.025+/-0.001 OF REF 10; ! ! end of exposure logsheet ! No scan data records found