Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5727 Report Date: 18-Jul-95:17:54 Version: ********** Check-in Date: ********** 1.Proposal Title: ACCRETION DISK MAPPING IN ECLIPSING CATACLYSMIC VARIABLES - REPEAT FOR HOPR#85. ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID STELLAR ASTROPHYSICS GO/CAR 4914 Sub Category ERUPTIVE BINARIES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dr Keith D Horne UTRECHT NL DR ------------------------------------------------------------------------------------ 7. Abstract We will use the FOS in RAPID readout mode to obtain time-resolved ultraviolet spectrophotometry of accretion disk eclipses in a long-period cataclysmic variable, the dwarf nova IP Peg, in outburst and quiescence. From the eclipse data in the UV lines and continuum, we will map the structure of the hot inner accretion disk, boundary layer, and stream-disk interaction region using a combination of light- curve synthesis and maximum entropy mapping techniques. The principle goal of this experiment is to study the structure of accretion disks in order to test accretion disk models that are applied widely throughout astrophysics, e,g, in models of protostars and active galactic nuclei. The observations will also permit a study of the geometry of winds in these systems, and more accurate determinations of the masses, radii, and temperatures of the primary and secondary stars, which will contribute to our understanding of the evolution of close binary systems. NOTE: TAC has cut the UX UMa observations from this proposal. NOTE: This repeats 2 G160L eclipses ala HOPR#85. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 10.32 par: 0 10. Num targs pri: 2 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOS ------------------------------------------------------------------------------------ 12. Special sched req: Time Critical obs. ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5727 PI: Dr Keith D Horne Proposal Title: ACCRETION DISK MAPPING IN ECLIPSING CATACLYSMIC VARIABLES - REPEAT FOR HOPR#85. ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Keith D Horne UTRECHT UNIVERSITY NL Heinz Barwig UNIVERSITY OF MUNICH GERMANY X Knox Long STSCI USA Karl-Heinz Mantel UNIVERSITY OF MUNICH GERMANY X Thomas R Marsh OXFORD UNIVERSITY UK X Ronald S Polidan NASA/GSFC USA John C Raymond CENTER FOR ASTROPHYSICS USA Edward L Robinson UNIVERSITY OF TEXAS USA Rene Rutten STERRENKUNDIG INSTITUUT "ANTON NETHERLANDS X PANNEKOEK", AMSTERDAM Allen W Shafter SAN DIEGO STATE UNIVERSITY USA Paula Szkody UNIVERSITY OF WASHINGTON USA Richard A Wade PENN STATE UNIVERITY USA Janet H Wood UNIVERSITY OF KEELE UNITED KING X Er-Ho Zhang UNIVERSITY OF TEXAS AT AUSTIN USA Page 3 ------------------------------------------------------------------------------------ 3. Description of proposed observations. ******Section 3 text from 3683********************************************** We will observe 3 eclipses of IP Peg in quiescence, and 4 eclipses of IP Peg near the peak and on the decline from an outburst. We will rely upon the AAVSO to inform us when an outburst of IP Peg begins, and the HST observations of IP Peg declining from outburst should begin within 2-4 days later. For each eclipse, binary phases -0.15 thru +0.15 should ideally be covered to include the eclipse of the disk with enough baseline on either side to establish the out-of-eclipse spectrum. This would require 68 minutes for IP Peg (Porbit=228m). We settle here for ~49min exposures covering phases -0.10 to +0.11. IP Peg 's binary period is approximately 2.38 HST orbit periods, thus an opportunity to observe an eclipse may occur every 5 HST orbits. Observing a minimum of three eclipses will help us to distinguish systematic eclipse features from random flickering variations that are characteristic of cataclysmic variables. The mean of the three eclipses will be used to study the disk structure, while the residuals after subtracting the mean eclipse will inform us about the variability properties of different parts of the disk. For IP Peg in quiescence, the 3 eclipses should be obtained as close together in time as possible in order to minimize the effect of secular variations in the disk structure. For IP Peg in outburst we wish to obtain 4 eclipses spaced by about 1 day in order to follow the propogation of cooling fronts as the disk declines from outburst. We will use the Blue Digicon with G160L disperser, which gives spectral coverage at 6.5A/pixel from 1150 to 2300A, and the Red Digicon with PRISM disperser, which covers 1700 to 9000A with variable resolution. These low dispersions provide the broadest possible wavelength coverage with sufficient resolution to isolate the strong but widely- spaced emission lines from the continuum. Our interest lies primarily in eclipses of continuum and emission line fluxes rather than in velocity profiles of the lines. The zero-order spectrum available with the G160L grating will provide a simultaneous optical light curve. For IP Peg in quiescence we will observe the first and third eclipses with FOS,BLUE,G160L and the second with FOS,RED,PRISM. The red spectra covering the MgII emission line and the Balmer continuum and line emission will help to constrain optically-thin regions such as the disk chromosphere. Both the red and blue configurations cover the 1700-2300A region, from which we will construct the best mean UV continuum light curve. For IP Peg in outburst we use FOS,BLUE,G160L for all 4 eclipses. ***************************************************************************** This proposal, 4914, repeats 2 eclipses with G160L. Page 4 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. ******Section 3 text from 3683********************************************** We request time-critical observations for two reasons. First, the observations must cover specific orbital phases centered on eclipse. Second, we must observe three eclipses of each star so we can identify features in the light curves caused by flickering variations as opposed to eclipses. The cataclysmic variables vary secularly, and as the time interval between the eclipses increases, the size of secular changes in the systems will increase. All observations of a given target should, if possible, be obtained within a period of one or two weeks to minimize the effect of these secular variations. The secular variations also make it difficult to construct eclipse light curves by joining parts of many different eclipses. Whole eclipses must be observed whenever possible. To observe whole eclipse light curves, it is necessary to have uninterrupted long exposures. We request target of opportunity status for part of the observations intended to catch eclipses of IP Peg in outburst. The recurrence time for IP Peg is about 60- 100 days; the probability of occurrence is high, but our understanding of the outbursts is too primitive to predict in advance when outbursts will occur. We will arrange for the AAVSO to monitor IP Peg and alert us when an outburst occurs. The decline from outburst generally begins 3-5 days after the rise, so a 2-3-d response should make it possible for the eclipses to occur near the peak or early decline of the outburst. *********************************************************************** This proposal, 4914, repeats 2 eclispes with G160L. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. Instrument Mode Special Calibration Requirement __________ _______ ________________________________ FOS/BL G160L Observe a flux standard that does not saturate the zero-order spec ------------------------------------------------------------------------------------ 8. Additional comments or special requests. The proposed HST observations form a self contained experiment: the eclipse analyses will yield new and significant information even if no other data are available. We feel strongly, however, that the scientific results of the eclipse analyses will be enhanced if the spectrophotometry from HST is complemented by photometry or spectrophotometry at other wavelengths. We will therefore attempt to obtain contemporaneous or even simultaneous observations at other wavelengths. For this purpose we have access to ground-based telescopes at the McDonald, La Palma, Mt. Laguna, Mt. Wendelstein, Manastash Ridge, Mount Hopkins, and Kitt Peak observatories, and we will request observing time on these telescopes for supporting eclipse observations at visual and near-infrared wavelengths. We also have access to the Voyager spacecraft with which we will attempt to obtain far-UV coverage of UX UMa eclipses. Our team has experience from several previous experiments involving simultaneous ground- and satellite-based observations. (NOTE: TAC has cut the UX UMa observations from this proposal.) ------------------------------------------------------------------------------------ 11. Address Information Name: KEITH HORNE Category: PI Institution: University of Utrecht Address: Astronomical Institute Postbus 8000 Pricnetonplein 5 City: Utrecht State: Zip Code: 3508-TA Country: NL Telephone: 31-30-535234 Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5727 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 IP-PEG A,149,161 PLATE-ID = 02BB, J2000 1 V = 15 +/- 1 RA = 23H 23M 8.61S +/- 0.5", 1 B-V = 0.2 DEC = +18D 24' 59.5" +/- 1 F-CONT(1500) = 1 +/- 1 E-14 0.5" 2 V = 11 +/- 1 2 B-V = 0.0 2 F-CONT(1500) = 1 +/- 1 E-13 Comments: DWARF NOVA V=11 IN OUTBURST, V=14-16 IN QUIESCENCE. ECLIPSING STAR, V=18 IN ECLIPSE. ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5727 [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 IP-PEG FOS/BL ACQ/ 4.3 G160L SEARCH-SIZE-X=1 1 15S 1 1 ONBOARD ACQ FOR 2 PEAK SEARCH-SIZE-Y=3 SEQ 1-6 WITHIN 1D SCAN-STEP- CYCLE 4 / 1-6 Y=1.204 ------------------------------------------------------------------------------------------------------------------------------------ 2 IP-PEG FOS/BL ACQ/ 1.0 G160L SEARCH-SIZE-X=6 1 15S 1 1 ONBOARD ACQ FOR 3 PEAK SEARCH-SIZE-Y=2 SCAN-STEP- X=.602 SCAN-STEP- Y=.602 ------------------------------------------------------------------------------------------------------------------------------------ 3 IP-PEG FOS/BL RAPID 4.3 G160L 1500 READ-TIME=6.18 1 2447.28 1 NON-INT PERIOD 0.15820613D +/- 0.00000004D ZERO-PHASE JD2445615.4156 +/- 0.001D Comments: MUST COVER PHASES -0.08 TO PHASE 0.92 +/- +0.10. BINARY PERIOD IS NEAR 0.025 2.36 HST ORBITS, THUS ECLIPSE WINDOW OCCURS EVERY 5TH HST ORBIT. ------------------------------------------------------------------------------------------------------------------------------------ 4 IP-PEG FOS/BL ACQ/ 4.3 G160L SEARCH-SIZE-X=1 1 15S 1 1 ONBOARD ACQ FOR 5 PEAK SEARCH-SIZE-Y=3 SCAN-STEP- Y=1.204 ------------------------------------------------------------------------------------------------------------------------------------ 5 IP-PEG FOS/BL ACQ/ 1.0 G160L SEARCH-SIZE-X=6 1 15S 1 1 ONBOARD ACQ FOR 6 PEAK SEARCH-SIZE-Y=2 SCAN-STEP- X=.602 SCAN-STEP- Y=.602 ------------------------------------------------------------------------------------------------------------------------------------ 6 IP-PEG FOS/BL RAPID 4.3 G160L 1500 READ-TIME=6.18 1 2447.28 1 NON-INT PHASE 0.92 +/- 0.025 OF REF 3 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5727 [ 7] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/PEAK RAPID ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE-X=1 SEARCH-SIZE-Y=3 SCAN-STEP-Y=1.204 SEARCH-SIZE-X=6 SEARCH-SIZE-Y=2 SCAN-STEP-X=.602 SCAN-STEP-Y=.602 READ-TIME=6.18 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO/CAR ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 10.32 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR ASTROPHYSICS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ERUPTIVE BINARIES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2; SEQ 1-6 WITHIN 1D; CYCLE 4 / 1-6 ONBOARD ACQ FOR 3; NON-INT; PERIOD 0.15820613D +/- 0.00000004D; ZERO-PHASE JD2445615.4156 +/- 0.001D; PHASE 0.92 +/- 0.025; ONBOARD ACQ FOR 5; ONBOARD ACQ FOR 6; PHASE 0.92 +/- 0.025 OF REF 3; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G160L ------------------------------------------------------------------------------------------------------------------------------------ Target Names IP-PEG ------------------------------------------------------------------------------------------------------------------------------------