! File: 3238C.PROP ! Database: PEPDB ! Date: 18-FEB-1994:23:10:56 coverpage: title_1: ECLIPSES OF CATACLYSMIC VARIABLE STARS sci_cat: STELLAR ASTROPHYSICS proposal_for: GTO/HSP cont_id: 1092 pi_fname: ROBERT pi_mi: C. pi_lname: BLESS pi_inst: WISCONSIN, UNIVERSITY OF pi_country: USA keywords_1: CATACLYSMIC VARIABLE STARS hours_pri: 5.33 num_pri: 2 time_crit: X ! end of coverpage abstract: line_1: The cataclysmic variables are close binary stars line_2: consisting of a late-type star and white dwarf. Mass line_3: is being transferred from the late-type star to the line_4: white dwarf. Unless the white dwarf has an extremely line_5: strong magnetic field, the transferred mass forms an line_6: accretion disk around the white dwarf. An important line_7: reason to observe the cataclysmic variables is that line_8: they provide an unparalled way to study nearly all line_9: aspects of the accretion of gas onto compact line_10: objects. We propose to observe the eclipses of line_11: several cataclysmic variables. The eclipse light line_12: curves can be used to find information about the line_13: geometry and physical conditions in the accretion line_14: disk. One star we propose to observe, Z Cha, is a line_15: dwarf nova. Eclipse observations of this star will line_16: provide information about changes in the structure line_17: of the accretion disk over the outburst cycle. line_18: Revision History: Prepared for future cycles line_19: submission--BJW 4/22/92; ! ! end of abstract general_form_proposers: lname: ROBINSON fname: EDWARD mi: L. inst: TEXAS, UNIVERSITY OF country: USA ! lname: BLESS fname: ROBERT mi: C. inst: WISCONSIN, UNIVERSITY OF country: USA ! lname: VAN CITTERS fname: G. mi: W. inst: NATIONAL SCIENCE FOUNDATION country: USA ! lname: DOLAN fname: JOSEPH mi: F. inst: NASA, GODDARD SPACE FLIGHT CENTER country: USA ! lname: WHITE fname: RICHARD mi: L. inst: SPACE TELESCOPE SCIENCE INSTITUTE country: USA ! lname: ELLIOT fname: JAMES mi: L. inst: MASSACHUSETTS INSTITUTE OF TECHNOLOGY country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: We propose to obtain high speed ultraviolet line_2: photometry of the two eclipsing cataclysmic line_3: variables Z Cha (orbital P = 1 hr. 47 min.) and line_4: V2051 Oph (orbital P = 1 hr. 30 min.). Z Cha is an line_5: erupting dwarf nova with outbursts approximately line_6: every 60 days; V2051 Oph is a nova-like variable line_7: which does not erupt and will serve as a "control". line_8: We plan to obtain 20 observations of Z Cha, at line_9: approximately 3 day intervals, each observation line_10: lasting for two hours. Similarly, we plan to line_11: observe V2051 Oph at four times separated by one to line_12: three weeks during this same period. Cycle 1 ! question: 4 section: 1 line_1: The eclipses of the white dwarf and surrounding line_2: accretion disk by the late type secondary will have line_3: the greatest contrast in the ultraviolet where the line_4: peak flux is emitted. The functional dependance of line_5: disk temperature on radius reveals that observations line_6: at 1200 A probe a region of the disk 4 times closer line_7: to the white dwarf than observations at 3500 A. line_8: Furthermore, accurate eclipse profiles can be line_9: obtained from ST, undistorted by transparency line_10: changes and scintillation noise, which affect ground line_11: based data. ! question: 13 section: 1 line_1: Multicolor ultraviolet photometry of the two line_2: eclipsing cataclysmic variables Z Cha (dwarf nova line_3: with orbital P = 1 hr. 47 min.) and V2051 Oph line_4: (nova-like with orbital P = 1hr. 30 min.) is line_5: proposed. A differential analysis of Z Cha in line_6: eruption, compared to V2051 Oph, will yield line_7: important clues as to the changes in the physical line_8: and geometric properties of accretion disks. ! !end of general form text general_form_address: lname: ROBINSON fname: EDWARD mi: L. category: CON inst: UNIVERSITY OF TEXAS addr_1: ASTRONOMY DEPARTMENT city: AUSTIN state: TX zip: 78712 country: USA phone: (512)471-4461 ! lname: BLESS fname: ROBERT mi: C. category: PI inst: UNIVERSITY OF WISCONSIN addr_1: WASHBURN OBSERVATORY addr_2: 475 N. CHARTER STREET city: MADISON state: WI zip: 53706 country: USA phone: (608)262-1715 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: V2051-OPH descr_1: A,151 pos_1: RA = 17H 8M 19.126S +/- .5", pos_2: DEC = -25D 48' 28.873" +/- .5" equinox: 2000 pm_or_par: NO plate_req: NO comment_1: POSREF = SIMBAD comment_2: NOVA-LIKE VARIABLE fluxnum_1: 1 fluxval_1: V = 15 +/- 2 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.500 targname: V2051-OPH config: HSP/UV1 opmode: ACQ num_exp: 1 time_per_exp: 72S fluxnum_1: 1 priority: 2 param_1: DATA-FORMAT=WORD, req_1: ONBOARD ACQ FOR 2; req_2: CYCLE 2 / 1.5-2; req_3: PCS MODE FINE / 1.5-2; ! linenum: 2.000 targname: V2051-OPH config: HSP/UV1 opmode: SINGLE aperture: 1.0 sp_element: F145M num_exp: ^ time_per_exp: 45M fluxnum_1: ^ priority: ^ req_1: REPEAT 1.5-2 EVERY 14D +/- req_2: 7D FOR 1 MORE TIMES; req_3: PHASE 0.8 +/- 0.1; req_4: PERIOD 0.062427887D +/- 0.000000008D; req_5: ZERO-PHASE JD2444043.68012 +/- 0.00012D; comment_1: FOR LINE 2, GAPS DUE TO EARTH comment_2: OCCULTATION SHOULD BE MINIMIZED. comment_3: MAX OBS W/IN ONE ORBIT. comment_4: OF EACH TARGET, UNTIL THE SYSTEM IS comment_5: CAPABLE OF RE-USING GUIDE STARS. comment_6: ORBITAL EPHEMERIS IS HELIOCENTRIC. ! ! end of exposure logsheet ! No scan data records found