Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5495 Report Date: 18-Jul-95:17:31 Version: ********** Check-in Date: ********** 1.Proposal Title: UV EMISSION LINE FORMATION PROCESSES AROUND THE BRIGHTEST HERBIG AE STAR HD104237 CYCLE 4 - MED ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID COOL STARS GO Sub Category EARLY EVOLUTION ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dr. Alexander Brown U. OF COLORADO USA (303) 492-7810 SENIOR RES ASSOCIATE ------------------------------------------------------------------------------------ 7. Abstract Herbig Ae stars are intermediate mass pre-main sequence (PMS) stars, and the more massive counterparts of the well-known T Tauri stars. Their evolution and atmospheric properties are still poorly understood. We propose to study the profiles of emission lines formed in the outer atmosphere/ circumstellar regions of the brightest and closest Herbig Ae star, HD104237, using GHRS spectra at moderate and high resolution of selected high temperature emission lines. At present it is not clear if these lines form in a stellar wind, an accretion disk, or a classical transition region (TR)/chromosphere. The emission line profiles will be analyzed to investigate atmospheric (density and temperature structure) and wind (mass loss rate, velocity and density laws) properties of this star. One goal is to discover if the winds from Herbig Ae stars can totally dominate the atmospheric structure of the star with TR plasma forming an integral part of the stellar wind or if physically separate, stationary, confined regions exist at the base of the wind. We shall determine quantitative constraints on the non-radiative heating, accretion and mass loss processes in the atmosphere, which will allow a better understanding of the evolution of PMS stars, since the heating and mass loss are driven by processes related to the sub-photospheric stellar structure. ------------------------------------------------------------------------------------ 8. Scientific Key Words: HERBIG AE STAR ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 3.99 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5495 PI: Dr. Alexander Brown Proposal Title: UV EMISSION LINE FORMATION PROCESSES AROUND THE BRIGHTEST HERBIG AE STAR HD104237 CYCLE 4 - MED ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Alexander Brown 1764 USA Jeffrey L. Linsky 1764 USA Philip Bennett 1764 USA Stephen L. Skinner 6510 JAPAN Peter Blondel 6810 NETHERLANDS Herman R. Tjin A Djie 6810 NETHERLANDS ------------------------------------------------------------------------------------ 3. Description of proposed observations. Our proposed observations will provide the first high-quality (S/N = 15- 100) line profiles for emission lines of H I (1216A), Si III (1206A), O V (1218A),O I (1302,4,6 + S I, Si II), C II (1335A), Si IV (1396,1403A) O IV (1402,140)7, C IV (1548,1550A) and Mg II (2796,2803A). All of these spectra will be obtained with the G160M grating, except for Mg II which will be obtained with ECH-B. G140L spectra of the 1170-1700 A region will be obtained so that emission lines too weak to be detected by IUE can be measured. The observations requested in Phase 1 were: Central Strong GHRS grating Wavelength(s) Aperture Exposure S/N Features Time G160M 1216 LSA 11 min 30 H I/Si III/O V G160M 1302 LSA 12 min 30 O I/S I G160M 1335 LSA 20 min 15 C II G160M 1400 LSA 45 min 31 Si IV 10 O IV G160M 1550 LSA 34 min 20 C IV ECH-B 2799 LSA 5 min 100 Mg II G140L 1305,1575 LSA 5,10min 50 ...... The quoted signal-to-noise values refer to the peak of the strongest emission line in the particular spectrum. TO FIT OUR ALLOCATION THE 1335 A EXPOSURE IS ELIMINATED AND THE 1216 A EXPOSURE HALVED ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The data required for this program consists of UV spectra not obtainable from the ground. IUE has been used extensively to study this target to the limits of its capability (including high resolution exposures up to 16 hours), and further observational advances depend on the acquisition of higher S/N spectra with GHRS. The increased sensitivity, wavelength resolution, dynamic range and S/N characteristics of the GHRS over those obtainable with the IUE (Carpenter et al. 1992, Ap.J. Lett., 377, L45.) will allow more accurate and detailed modelling of physical processes occurring in the outer atmosphere of HD104237. Only the GHRS is capable of providing us with the high precision line profiles, fluxes, and absolute velocities required for our program. ONLY GHRS CAN PROVIDE THE LINE PROFILES OF OPTICALLY-THIN, DENSITY-SENSITIVE EMISSION LINES. . The exposures requested are summarized in section 2. The exposure times have been estimated using absolute fluxes previously measured with the IUE. For the first order and echelle gratings we used sensitivity values given in the GHRS instrument handbook. The LSA is used. ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. No real-time observations or special scheduling is required. Page 3 ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. Internal Pt lamp SPYBAL spectra should provide a sufficiently accurate wavelength scale for our first order grating observations. We include a WAVE observation for our single echelle (Mg II 2800 A) observation, so that precise measurements of the interstellar and circumstellar absorption velocities can be made. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. None. ------------------------------------------------------------------------------------ 9. Description of previous HST work. GO Program 3626 - Empirical determination of the wind velocity and density laws for the K supergiant Zeta Aurigae from eclipse ingress Spectra (A. Brown PI, J. Linsky, R. Weyman, D. Reimers, R. Baade, T. Kirsch) ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Software developed by the GHRS IDT and the proposers will be used in the reduction and analysis of these observations. A workstation at JILA connected to the CASA cluster is available for data reduction and analysis. ------------------------------------------------------------------------------------ 11. Address Information Name: Alexander Brown Category: PI Institution: Joint Institute for Laboratory As Address: University of Colorado City: Boulder State: CO Zip Code: 803090440 Country: USA Telephone: (303) 492-7810 Telex (or e-mail): 755842 JILA ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5495 [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 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 HD104237 A,127 RA=11H57M33.47S+/-0.15S, 1950 V=0.0 1 V=6.5 DEC=-77D54'50.5"+/-0.5" Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) B 1950.00 -0.0162 +/- 0.0010 0.0140 +/- 0.0070 0.0000 +/- 0.0000 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5495 [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 HD104237 HRS ACQ 2.0 MIRROR-A2 SEARCH-SIZE=3 1 9S 1 ONBOARD ACQ FOR 12 BRIGHT=RETURN CYCLE 4/10-55 GROUP 10-55 NO GAP Comments: STEP TIME = 1 SEC EXPECTED A2 COUNTS ARE APPROX. 1500 PER SECOND ------------------------------------------------------------------------------------------------------------------------------------ 12 HD104237 HRS ACQ/ 2.0 MIRROR-A2 1 163.2S 1 1 ONBOARD ACQ FOR PEAKUP 21.0-55.0 Comments: STEP-TIME=1.6 SEC CENTER IN LSA AFTER NEW DEFCAL ------------------------------------------------------------------------------------------------------------------------------------ 21 HD104237 HRS ACCUM 2.0 G160M 1222.5 STEP-PATT=5 1 871.0S ^ FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 26 HD104237 HRS ACCUM 2.0 G160M 1302.0 STEP-PATT=5 1 762.0S ^ FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 36 HD104237 HRS ACCUM 2.0 G160M 1401.0 STEP-PATT=5 2 1415.0S ^ FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 41 HD104237 HRS ACCUM 2.0 G160M 1548.0 STEP-PATT=5 2 1088.0S ^ FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 45 WAVE HRS ACCUM SC2 ECH-B20 2800 STEP-PATT=3 1 32S ^ CALIB FOR 46 NO SLEW SEQ 45-46 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ 46 HD104237 HRS ACCUM 2.0 ECH-B20 2800 STEP-PATT=7 1 327S ^ FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 47 HD104237 HRS ACCUM 2.0 G140L 1305.0 STEP-PATT=5 1 436.0S ^ FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 55 HD104237 HRS ACCUM 2.0 G140L 1575.0 STEP-PATT=5 1 654.0S 1 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5495 [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAKUP ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE=3 BRIGHT=RETURN STEP-PATT=5 FP-SPLIT=STD STEP-PATT=3 STEP-PATT=7 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.99 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category COOL STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category EARLY EVOLUTION ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 12; CYCLE 4/10-55 ; GROUP 10-55 NO GAP ONBOARD ACQ FOR 21.0-55.0 CALIB FOR 46 NO SLEW; SEQ 45-46 NO GAP ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-A2 G160M ECH-B20 G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD104237 ------------------------------------------------------------------------------------------------------------------------------------