! Proposal 6770, submission 2 ! PI: Dr. Tim O'Brien ! Received Tue Feb 11 03:46:59 EST 1997 ! From: tob@staru1.livjm.ac.uk ! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /user3/tob/hst/6770.prop ! Generated by PREPROCESSOR, version 6.0e ! Date: Mon Feb 10 18:36:21 GMT 1997 Proposal_Information Title: Resolving the nature of nova shells Proposal_Category: GO Scientific_Category: INTERSTELLAR MEDIUM Cycle: 6 Investigators PI_Name: Dr. Tim O'Brien PI_Institution: Liverpool John Moores University CoI_Name: Dr. Huw Lloyd CoI_Institution: Liverpool John Moores University Contact: CoI_Name: Andrew Slavin CoI_Institution: Liverpool John Moores University Contact: CoI_Name: Prof. Mike Bode CoI_Institution: Liverpool John Moores University Contact: Abstract: We propose to conduct WFC observations of the nebular remnants of 11 novae. We have already demonstrated the usefulness of these observations with a deep, predominantly H alpha, imaging survey of 37 classical nova remnants using the William Herschel and Anglo-Australian Telescopes. This has resulted in the detection of new nebular remnants and the resolution of detailed structure in previously known remnants. The data indicate a strong correlation between nova speed class and the ellipticity of the resulting remnants - those of faster novae tend to comprise randomly distributed clumps of ejecta superposed on spherically-symmetric diffuse material, whilst slower novae produce more structured ellipsoidal remnants with at least one and sometimes several rings of enhanced emission. High-resolution optical images of these faint, and often rather small (several arcseconds) structures will enable us to classify them, thereby placing nova shell research on a similar footing to studies of the shaping of planetary nebulae. The results will have implications for the dynamics of common-envelopes, hydrodynamic instabilities and dust formation in novae, the calibration of the distance scale and the determination of ejecta masses. Questions Observing_Description: Our sample comprises 11 novae selected from those which we have recently observed using the WHT and AAT. The selection criteria are as follows: (i) The objects have not been previously observed or scheduled to be observed with the HST (excepting HR Del for which there is a pre-COSTAR saturated image in the data archive); (ii) A shell was detected in our ground-based survey; (iii) The objects cover a range of speed classes; (iv) The WFPC2 will provide an image of comparable quality (in terms of resolution) with our ground-based images of DQ Her. The exposure times for these observations have been calculated using our own ground-based images and the observed V magnitudes and colours of the central stars (from: Bruch & Engel 1994, A&A Supp. 104, 79; Szkody 1994, AJ, 108, 639; Warner 1986, MNRAS, 222, 11; AAVSO lists). We have compared the performance of the HST/WFC with the WHT in order to assess the relative quality of the ground-based and proposed HST images. Allowing for the differences in system throughput (effective areas, filter efficiency, instrument throughput, detector efficiency) we find that the WHT is 5* more efficient than the HST/WFC. For point sources, allowing for the difference in pixel scale and FWHM of the PSF, we find that the WHT is about 1.8* more efficient than the HST/WFC and about 2-3* more efficient than the HST/PC. This implies that if the emission from the shell of FH Ser were entirely contributed by point sources then a WFC image at the same signal to noise as our ground-based data but with 20* better resolution (assuming a dither) could be obtained with an HST exposure of about 500 seconds. However, the shell is unlikely to be composed entirely of unresolved point sources, hence this figure can only be considered a lower limit. As we have no way of knowing the actual structure of the shell before these observations are made we have taken total exposure times of one orbit. The larger remnants (RR Pic and T Aur) have been placed on the geometric centre of the WF3 chip. The smaller objects (diameters less than about 10") have been placed on the centre of the PC chip. For the WF3 observations we have specified a default line-type dither in order to improve the spatial resolution. However, because we are not only interested in spatial resolution but also in detecting faint features we have decided not to split each of these exposures in order to identify cosmic rays. Instead we propose to use the two dithered exposures -- we believe that cosmic ray removal by inspecting re-sampled images will be sufficient for our purposes. In the PC1 exposures we have specified a default cosmic-ray split into two sub-exposures. For HR Del, the nebular emission is relatively bright and so to be sure of avoiding saturation of the shell we have specified three separate exposures of this object within the orbit. We are only concerned with the extended faint nebular emission so saturation of the central system in several of these exposures is not avoided. The saturation is not extreme and so blooming will only affect a small region at the centre of the nebular remnants and will not compromise our scientific aims. All the images will use the F656N HAlpha filter. Experience has shown us that these nebular objects are brightest in this line; this will also reduce the relative contribution of the bluer central stars. The bandpass of this filter should enable us to image the whole of the principal ejecta in the majority of our targets. An ADC gain of 7 e/DN was chosen in every case in order to reduce the contribution of readout noise. Real_Time_Justification: Calibration_Justification: Additional_Comments: Fixed_Targets Target_Number: 1 Target_Name: FH-SER Alternate_Names: NOVA-SER-1970 Description: STAR,CLASSICAL NOVA,ISM,EJECTA Position: RA=18H 30M 47.06S +/- 3",DEC=02D 36' 52.71" +/- 3",PLATE-ID=050S Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 13.5+/-0.5 Comments: Target_Number: 2 Target_Name: V1500-CYG Alternate_Names: NOVA-CYG-1975 Description: STAR,CLASSICAL NOVA,ISM,EJECTA Position: RA=21H 11M 36.56S +/- 3",DEC=48D 09' 02.73" +/- 3",PLATE-ID=02RW Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 16.0+/-1.5 Comments: Target_Number: 3 Target_Name: HR-DEL Alternate_Names: NOVA-DEL-1967 Description: STAR,CLASSICAL NOVA,ISM,EJECTA Position: RA=20H 42M 20.38S +/- 3",DEC=19D 09' 39.72" +/- 3",PLATE-ID=02UR Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 12.0+/-0.5 Comments: Target_Number: 4 Target_Name: RR-PIC Alternate_Names: NOVA-PIC-1925 Description: STAR,CLASSICAL NOVA,ISM,EJECTA Position: RA=06H 35M 36.10S +/- 3",DEC=-62D 38' 23.7" +/- 3",PLATE-ID=00MS Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 12.0+/-0.5 Comments: Target_Number: 5 Target_Name: T-AUR Alternate_Names: NOVA-AUR-1891 Description: STAR,CLASSICAL NOVA,ISM,EJECTA Position: RA=05H 31M 59.13S +/- 3",DEC=30D 26' 44.98" +/- 3",PLATE-ID=00DH Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 15+/-1.0 Comments: Target_Number: 6 Target_Name: V533-HER Alternate_Names: NOVA-HER-1963 Description: STAR,CLASSICAL NOVA,ISM,EJECTA Position: RA=18H 14M 20.51S +/- 3",DEC=41D 51' 22.27" +/- 3",PLATE-ID=02S0 Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 14.8+/-0.5 Comments: Target_Number: 7 Target_Name: V842-CEN Alternate_Names: NOVA-CEN-1986-2 Description: STAR,CLASSICAL NOVA,ISM,EJECTA Position: RA=14H 35M 52.58S +/- 3",DEC=-57D 37' 34.9" +/- 3",PLATE-ID=039T Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 18.0+/-1.0 Comments: Central star likely to be brighter than quoted flux which is from quiescence. However exact brightness unknown and in any case saturation does not affect our scientific aims. Target_Number: 8 Target_Name: V476-CYG Alternate_Names: NOVA-CYG-1920 Description: STAR,CLASSICAL NOVA,ISM,EJECTA Position: RA=19H 58M 24.50S +/- 3",DEC=53D 37' 07.61" +/- 3",PLATE-ID=00VQ Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 15.0+/-1.0 Comments: Target_Number: 9 Target_Name: DK-LAC Alternate_Names: NOVA-LAC-1950 Description: STAR,CLASSICAL NOVA,ISM,EJECTA Position: RA=22H 49M 46.93S +/- 3",DEC=53D 17' 20.46" +/- 3",PLATE-ID=036H Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 14.0+/-1.0 Comments: Target_Number: 10 Target_Name: DY-PUP Alternate_Names: NOVA-PUP-1902 Description: STAR,CLASSICAL NOVA,ISM,EJECTA Position: RA=08H 13M 48.44S +/- 3",DEC=-26D 33' 56.9" +/- 3",PLATE-ID=04NO Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 16+/-1.0 Comments: Target_Number: 11 Target_Name: BT-MON Alternate_Names: NOVA-MON-1939 Description: STAR,CLASSICAL NOVA,ISM,EJECTA Position: RA=06H 43M 47.20S +/- 3",DEC=-02D 01' 14.46" +/- 3",PLATE-ID=02O8 Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 16+/-1.0 Comments: Solar_System_Targets Generic_Targets Scan_Data Visits Visit_Number: 01 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 10 Target_Name: FH-SER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 2400S Special_Requirements: Comments: Visit_Number: 02 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 20 Target_Name: V1500-CYG Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 2600S Special_Requirements: Comments: Visit_Number: 03 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 30 Target_Name: HR-DEL Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 1600S Special_Requirements: Comments: Exposure_Number: 31 Target_Name: HR-DEL Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 700S Special_Requirements: Comments: Visit_Number: 04 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 40 Target_Name: RR-PIC Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F656N Wavelength: Optional_Parameters: DITHER-TYPE=LINE,CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1200S Special_Requirements: Comments: Visit_Number: 05 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 50 Target_Name: T-AUR Config: WFPC2 Opmode: IMAGE Aperture: WF3-FIX Sp_Element: F656N Wavelength: Optional_Parameters: DITHER-TYPE=LINE,CR-SPLIT=NO Number_of_Iterations: 1 Time_Per_Exposure: 1100S Special_Requirements: Comments: Visit_Number: 06 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 60 Target_Name: V533-HER Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 2600S Special_Requirements: Comments: Visit_Number: 07 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 70 Target_Name: V842-CEN Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 2700S Special_Requirements: Comments: Visit_Number: 08 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 80 Target_Name: V476-CYG Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 2600S Special_Requirements: Comments: Visit_Number: 09 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 90 Target_Name: DK-LAC Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 2600S Special_Requirements: Comments: Visit_Number: 10 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 100 Target_Name: DY-PUP Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 2500S Special_Requirements: Comments: Visit_Number: 11 Visit_Requirements: On_Hold_Comments: Visit_Comments: Exposure_Number: 110 Target_Name: BT-MON Config: WFPC2 Opmode: IMAGE Aperture: PC1-FIX Sp_Element: F656N Wavelength: Optional_Parameters: CR-SPLIT=0.5 Number_of_Iterations: 1 Time_Per_Exposure: 2500S Special_Requirements: Comments: Data_Distribution ! 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