Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 1254c Report Date: 09-May-96:16:23 Version: ********** Check-in Date: ********** 1.Proposal Title: CENTRAL STARS OF PLANETARY NEBULAE ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID STELLAR ASTROPHYSICS GTO/FOC Sub Category SUBLUMINOUS STARS ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone T. M. Kamperman SRON SPACE RESEARCH UTRECHT NETHERLAND 3130535715 ------------------------------------------------------------------------------------ 7. Abstract It has proved impossible to detect the very hot exciting stars of some planetary neblae from the ground. This is probably because these stars emit a great many ionizing photons for each visible quantum. The ionized nebula is therefore so extensive that the nebular emission, both line and continuum, completely dominate the visual continuum emission of the central star, which becomes lost in the noise. Observing above the atmosphere increases the possibility of detection of these central star by a factor of at least 400. A factor ~ 100 because the light of the central star is within an image of. 1" instead of the ~ 1" ground seeing limitation allowing better discrimination of the star against the diffuse nebular continuum and a further factor ~ 4 occurs because the star is that much brighter, relative to the nebula, in the ultraviolet than it is in the visible. With the spherical abberation of HST, the above mentioned factor of 100 is reduced to about 15, but as the UV adventage remains, detectability is still several magnitudes beyond groundobservations. ------------------------------------------------------------------------------------ 8. Scientific Key Words: PLANETARY NEBULAE, HOT CENTRAL STARS. ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 1.00 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 1254c PI: T. M. Kamperman Proposal Title: CENTRAL STARS OF PLANETARY NEBULAE ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ N. K. Reay IMPERIAL COLLEGE, LONDON UNITED KING X P. D. Atherton GRONINGEN, UNIVERSITY OF NETHERLANDS X S. R. Pottasch GRONINGEN, UNIVERSITY OF NETHERLANDS X N. Walton GRONINGEN, UNIVERSITY OF NETHERLANDS X T. M. Kamperman SRON SPACE RESEARCH UTRECHT NETHERLANDS X ------------------------------------------------------------------------------------ 3. Description of proposed observations. For each object 3 exposure images will be taken through different narrow band U.V. filters. The filters are chosen so that we avoid areas of the spectrum with strong emission lines, and seperated by a reasonable wavelength interval. This serves two purposes. a) We will be able to discriminate between low temperature field stars and the true central star by measuring their colour temperature, b) If there is an enhancement in the nebular continuum surrounding the central star, we will be able to seperate the contributions from the nebular and stellar continuum surrounding the central star, we will be able to seperate the contributions from the nebular and stellar continuum by their different gradients. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The combination of ultraviolet sensitivity and the much higher spatial resolution compared to ground-based work will increase the sensitivity for detection of the central stars by a factor of at least 400. With the abberated mirror this factor is reduced to about 70. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). All three institutes have sufficient resources to support this project ------------------------------------------------------------------------------------ 13. UV OBSERVATION OF VERY HOT, HIGH MASS CENTRAL STARS OF PLANETARY NEBULAE ------------------------------------------------------------------------------------ 11. Address Information Name: T. M. KAMPERMAN Category: PI Institution: SRON SPACE RESEARCH UTRECHT Address: SORBONNELAAN 2 3584 CA City: UTRECHT State: Zip Code: Country: NETHERLANDS Telephone: Telex (or e-mail): NL 47224 ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 1254c [ 3] ------------------------------------------------------------------------------------------------------------------------------------ 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 NGC7027 CENTRAL STAR OF RA=21H07M1.7S+/-.5S, 2000 V=10 EXT 1 V=8.6+/-.2 PLANETARY NEBULA DEC=42D14'9.4"+/-2" 2 SURF(V)=14.4+/-1. 3 F(4861)=6.8+/-1.E-11 4 SURF(1500)=7.6+/-2.E-16 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1254c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 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 DEFINE # FOC/96 IMAGE 256X256 F130M 1 8M 4 # SIZE256 ------------------------------------------------------------------------------------------------------------------------------------ 2 DEFINE # FOC/96 IMAGE 256X256 F210M 1 8M 4 # SIZE256 ------------------------------------------------------------------------------------------------------------------------------------ 3 DEFINE # FOC/96 IMAGE 256X256 F278M 1 8M 4 # SIZE256 Comments: THIS 256 MODE APPLIES FOR SMALL NEBULAE WHERE CENTRAL OBJECT WILL BE WITHIN FIELD OF VIEW. MAGNITUDE CENTRAL STARS UNKNOWN. ------------------------------------------------------------------------------------------------------------------------------------ 4 USE NGC7027 1 CYCLE 1 SIZE256 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 1254c [ 5] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOC/96 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/FOC ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 1.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STELLAR ASTROPHYSICS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category SUBLUMINOUS STARS ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F130M F210M F278M ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC7027 ------------------------------------------------------------------------------------------------------------------------------------