Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 5358 Report Date: 18-Jul-95:17:14 Version: ********** Check-in Date: ********** 1.Proposal Title: THE CHROMOSPHERE OF ALPHA TAU - CYCLE 4 MEDIUM ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID COOL STARS GO Sub Category STELLAR ATMOSPHERES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Kenneth G. Carpenter NASA GODDARD LASP USA ------------------------------------------------------------------------------------ 7. Abstract We propose observations of the K5 III star Alpha Tau using the Goddard High- Resolution Spectrograph (GHRS), to follow-up on the exciting initial SAO observations of this star and the SV observations of the K5 III hybrid star Gamma Dra. These data will also allow a detailed comparison of its spectrum and the thermodynamic properties of its outer atmosphere with those of the cooler M giant and supergiant stars Gamma Cru and Alpha Ori, observed during previous cycles. We shall check for variations in the C II downflow discovered in the SAO observations and search for evidence of systematic flows in other emission lines. We shall make detailed comparisons of the chromospheric emission lines and wind signatures in the UV spectra of two stars of the same spectral class, where one is a hybrid and one is not. We shall search for evidence of shocks and/or propagating waves in the line variations predicted by our recent calculations. We will also determine the variation of wind velocity with height using semi-empirical non-LTE models assuming spherical symmetry, search for evidence of circumstellar and interstellar absorptions on resonance lines of O I, Fe II, and Mg II, and compare the short- wavelength continuum measured in this star with that detected in observations of Gamma Dra, Gamma Cru and Alpha Ori. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 6.00 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: HRS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 5358 PI: Kenneth G. Carpenter Proposal Title: THE CHROMOSPHERE OF ALPHA TAU - CYCLE 4 MEDIUM ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Pi Kenneth G. Carpenter NASA GODDARD LASP USA Philip G. Judge HIGH ALTITUDE OBSERVATORY USA Manfred Cuntz HIGH ALTITUDE OBSERVATORY USA Alexander Brown U.COLORADO JILA USA Richard D. Robinson COMPUTER SCIENCES CORPORATION USA Glenn M. Wahlgren COMPUTER SCIENCES CORPORATION USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. The observations requested are: GHRS Central grating Wavelength(s) Aperture Exposure Time(s) Strong Features G270M 2345 SSA 20 min C II]/Si II] G160M 1296 SSA 40 min Fe II/O I G160M 1550 SSA 60 min C IV/CO/contin. G160M 1655 SSA 40 min C I/O I/O III G200M 1994 SSA 20 min C III/C I] G270M 2753 SSA 10.9 min Fe II ECH-B 2799 SSA 14.51 min Fe II/Mg II G270M 2345 SSA 20 min C II]/Si II] The G270M 2345 A exposures will be taken at the start and end of the main observing session to check for short term changes in the chromospheric turbulence and flow velocities. Each exposure will be taken using FP-SPLIT=STD such that each of the subexposures will be no longer than five minutes in duration to minimize geomagnetic and thermal drifts in the spectrograph and to allow a search for chromospheric variations on a very short time scale. The project is pure Cycle 4: Primary Hours: Parallel Hours: Exposures: 5.96 0.0 8 ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The data required for this program consist of UV spectra not obtainable from the ground. IUE has been used to study this star to the limits of its ability (e.g. Brown and Jordan, 1981, MNRAS, 191,37; Judge, 1986, MNRAS, 223, 239). Further progress in the modelling process requires observations which only the GHRS can provide. For example, to search for weak CO absorption features and to study the continuum shape in the far UV requires high sensitivity detector with a very low background noise and small fixed pattern noise. Studying the shapes af the spectral lines for turbulence and small amplitude bulk flows requires a high S/N, large dynamic range and a very accurate wavelength calibration. A small number of exposures have been obtained with the GHRS as part of the Science Assessment Program which clearly demonstrate the increased sensitivity, wavelength resolution, dynamic range and S/N characteristics of the GHRS over that obtainable with the IUE (Carpenter et al. 1991, Ap.J. (letters), 377, L45). ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. The two C II] G270M exposures (at 2345 A) should be taken at the beginning and end of the observation sequence to allow the study of changes in turbulence, flow velocities and line profiles, all of which are sensitive probes of shock and wave passage through the atmosphere. The exposure logsheet contains "SEQ" special requirements to ensure the proper scheduling and no special handling should be required. Page 3 ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. We require the highest possible wavelength accuracy in order to measure absolute flow velocities in the chromosphere, wind and circumstellar shell of our target star (down to the 1 km/sec level in the medium and echelle observations) as well as aiding in the identification of the many weak features we expect in the low resolution data. Experience with SV and SAO data (Carpenter et al. 1991, HST Workshop) has demonstrated that the default calibration will produce uncertainties of up to 3 diodes due to magnetic and thermal drifts within the spectrograph. Using internal Pt lamp spectra taken during the SPYBAL procedures we can estimate the amount of drift and can therefore reduce the degree of uncertainty to about 0.5 diodes. To obtain the greatest possible wavelength accuracy we require dedicated WAVECAL exposures using the internal Pt lamps to be connected to each GHRS science exposure. Experience has shown that with care calibrations good to 0.1 diode can be obtained using this data. To do this the wavelength calibrations must be taken at the same carrousel position and close in time to the science exposures to remove uncertainties caused by the geomagnetic (GIMP) and thermal drifts which move the image around on the GHRS photocathode. Long exposures must be broken into time sequences of 5 minute integrations so that the drifts can be identified and corrected. ------------------------------------------------------------------------------------ 8. Additional comments or special requests. none Page 4 ------------------------------------------------------------------------------------ 9. Description of previous HST work. a. List HST program numbers and titles, and specify whether they are related to this project or not. GTO 1195: Outer Atmospheres of Cool Luminous Stars - Cycle 0 (Alpha Ori) 3212: Outer Atmospheres of Cool Luminous Stars - Cycle 1 (Gamma Cru) GTO 1198/4251 & 3934: Physical Conditions and Velocity Structures in the Red Giant Winds in the Binaries CI Cyg and EG And - Cycle 2 (2 targets) GTO 1199: Alpha Ori Team Project - Cycle 1 These proposals represent the GTO science program, as adjusted for spherical aberration, of GHRS IDT Co-I K. Carpenter. Programs 1195, 3212, and 1199 are related to this proposal. Proposals 1198/4251 & 3934 are studies of symbiotic stars and not directly related to the current proposal. SAO program 3023 (Alpha Tau) observations have been used to assess the feasibility of programs such as these which involve observations of narrow emission-line sources (see the Ap.J. reference below). NO FURTHER OBSERVATIONS OF ALPHA TAU ARE INCLUDED IN THE GTO PROPOSALS, AND NO ADDITIONAL GTO OBSERVATIONS, BEYOND THE CYCLE 0-1 OBSERVATIONS LISTED ABOVE, ARE PLANNED OF SINGLE COOL, LUMINOUS STARS. b. Summarize the main results obtained from previous related programs. Highlights include 1) the unambiguous detection of a far-UV continuum in Alpha Ori and Gamma Cru, which will provide a very important and previously unrecognized diagnostic of their chromospheric plasmas (formation temperature in Alpha Ori ranges from 3500-5000 K and increases steadily with decreasing wavelength), 2) the discovery of circumstellar CO (4th positive A-X system) absorption bands superposed on the far-UV continuum from Alpha Ori, providing a probe of regions of the circumstellar shell not available at visible or IR wavelengths (initial analysis indicates T=500 K, Vturb=5 km/s, N(CO)=1.0e18 cm-2), 3) detection of myriad new Fe II fluorescent line products, producing by Lyman Alpha radiation in Alpha Ori, 4) the determination that the O I and C I resonance line flux deficiencies are due to self-absorption in the chromosphere, 5) the determination that the differing Mg II (UV 1) line asymmetries are due to differing velocity shifts between the emission and self-absorption components rather than primarily due to overlying circumstellar absorption from Fe I and Mn I, and 5) the first direct measurement of the chromospheric turbulence (24 km/sec) and the detection of a downflow of about 4 km/sec in chromospheric C II] plasma in Alpha Tau. c. List publications resulting from the above data (Format: Title, Authors,Journal, Volume, Page, and Year.) Results have been presented: in the Ap.J. & MNRAS, at AAS meetings (1/91, 5/91 1/92, 1/93, & 6/93), the HST Joint Discussion at the IAU General Assembly (7/91), the 7th Cambridge Cool Star Workshop (10/91), and at both HST Workshops (5/91 & 7/92), including two invited reviews (AAS 1/91 and Cool Star Workshop 10/91). "GHRS Observations of Cool, Low-Gravity Stars. I. The Far-UV Spectrum of Alpha Ori (M2 Iab)", Carpenter, K., Robinson, R., Wahlgren, G., Linsky, J., and Brown, A., 1993 Ap.J., submitted. "A Search for Proton Beams Druing Flares on AU Mic", Robinson, R., Carpenter, K., Woodgate, B.W., and Maran, S.P. 1993 ApJ, in press. "Detection of A Proton Beam During the Impulsive Phase of A Stellar Flare," Woodgate, B., Robinson, R., Carpenter, K., Maran, S., and Shore, S. 1993 ApJ (Letters), 397, L95. "First Results from the Goddard High Resolution Spectrograph: The Chromosphere of Alpha Tauri", Carpenter, K., Robinson, R., Wahlgren, G., Ake, T., Linsky, J., Brown, A., and Walter, F., Ap.J. (Letters), 377, L45, 1991. "Si II Emission Line Diagnostics," Judge, P. G., Carpenter, K. G., and Harper, G.M., MNRAS, 253, 123, 1991. "Early Scientific Results from the Goddard High Resolution Spectrograph" Carpenter, K. G. , Invited Review presented at the AAS Meeting, 1/13-17/91. "GHRS Chromospheric Emission Line Spectra of the Red Giant Alpha Tau" Carpenter, K. G., Robinson, R. D., Ebbets, D. C., Brown, A., and Linsky, J., in `The First Year of HST Observations,' 1991. "Chromospheres and Winds of Cool Stars", Carpenter, K.G., IAU General Assembly Joint Discussion, 'First Results from the Hubble Space Telescope', 7/31/91. "HST Observations of Late-Type Stars," (Invited Review) Carpenter, K. G., in `Proceedings of the 7th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun,' eds. M. Giampapa & J. Bookbinder, A.S.P. Conference Series, 26, 17, 1992. "Molecular Absorption in the UV Spectrum of Alpha Ori," Wahlgren, G. M., Robinson, R. D., and Carpenter, K. G., Proceedings of the Seventh Cambridge Workshop on Cool Stars, Stellar Systems and the Sun, eds. M. Giampapa and J. Bookbinder, A.S.P. Conference Series, 26, 37, 1992. "The Chromosphere and Circumstellar Shell of Alpha Orionis as Observed with the Goddard High Resolution Spectrograph," Carpenter, K. G., Robinson, R. D., Wahlgren, G. M., Linsky, J. L., Brown, A., in Science with the Hubble Space Telescope, eds. P. Benvenuti and E. Schreier, ESO Conference and Workshop Proceedings No. 44, 387, 1992. "Plasma Flows in the Outer Atmosphere of Alpha Ori," Carpenter, K. G., Robinson, R. D., Wahlgren, G. M., Brandt, J.C., Linsky, J. L., Ebbets, D. and Weymann, R., BAAS, 24, #4, 1207, 1992. "The Ultraviolet Photospheric Spectrum of Alpha Orionis," Wahlgren, G. M., Robinson, R. D., and Carpenter, K. G., BAAS, 24, #4, 1280, 1992. "GHRS Spectroscopy of Cool Stars. I. O I and CO as Diagnostics of Winds and Circumstellar Shells" Carpenter, K., Robinson, R., Ebbets, D., Brown, A., Linsky, J., BAAS, 23, #2, 910, 1991. "GHRS Spectroscopy of Cool Stars. II. Gamma Draconis," Brown, A., Linsky, J., Carpenter, K., Robinson, R., Ebbets, D., BAAS, 23, #2, 910, 1991. "Molecular Absorption in the Ultraviolet Spectrum of Alpha Ori," Wahlgren, G.M., Robinson, R. D., and Carpenter, K. G., BAAS, 23, #4, 1386, 1991. (plus others) Page 5 ------------------------------------------------------------------------------------ 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 VAX cluster is available for data reduction and analysis at GSFC. ------------------------------------------------------------------------------------ 11. Address Information Name: KENNETH G. CARPENTER Category: PI Institution: NASA Goddard LASP Address: CODE 681 NASA/GSFC - LAB. FOR ASTRONOMY AND SOLAR PHYSICS City: GREENBELT State: MD Zip Code: 20771 Country: USA Telephone: (301)-286-3453 Telex (or e-mail): 89675 ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 5358 [ 6] ------------------------------------------------------------------------------------------------------------------------------------ 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 HD29139 A,140 RA=04H35M55.24S+/-0.1", 2000.0 V=+54 1 V=0.84+/-.2,TYPE=K5 III ALPHA-TAU DEC=+16D30'33.39"+/-0.1" 2 F(1314)=3.E-14 3 F(1655)=7.7E-13 4 F(1994)=4.E-13 5 F(2327)=4.E-12 6 F(2759)=1.5E-12 7 F(2770)=1.5E-12 8 F(2799)=8.E-11 Comments: NOTE: RA PROPER MOTION IS IN SEC OF TIME/YR **** COORDINATES ARE FROM HIPPARCOS CAT. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) B 2000.00 0.0045 +/- 0.0010 -0.1890 +/- 0.0010 0.0540 +/- 0.0050 ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5358 [ 7] ------------------------------------------------------------------------------------------------------------------------------------ 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 HD29139 HRS ACQ 2.0 MIRROR-A2 SEARCH-SIZE=5 1 10S 1 1 CYCLE 4 / 10-61 BRIGHT=RETURN ONBOARD ACQ FOR 11 SEQ 10-61 NO GAP Comments: STEP TIME = 0.4 SEC EXPECT 226 CTS/400 MSEC ------------------------------------------------------------------------------------------------------------------------------------ 11 HD29139 HRS ACQ/ 0.25 MIRROR-A2 SEARCH-SIZE=5 1 40.0S 1 1 ONBOARD ACQ FOR 12 PEAKUP -61 Comments: STEP-TIME=1.6SEC; EXP. TIME ASSUMES 3X3 SEARCH. ------------------------------------------------------------------------------------------------------------------------------------ 12 WAVE HRS ACCUM SC2 G270M 2345.0 STEP-PATT=3 1 3.2S 1 CALIB FOR 13 NO SLEW SEQ 12-13 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 13 HD29139 HRS ACCUM 0.25 G270M 2345.0 STEP-PATT=5 1 20.0M 35 5 1 FP-SPLIT=STD Comments: FIRST C II EXPOSURE (1 OF 2) ------------------------------------------------------------------------------------------------------------------------------------ 31 WAVE HRS ACCUM SC2 G160M 1296 STEP-PATT=3 1 3.2S 1 CALIB FOR 32 NO SLEW SEQ 31-32 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 32 HD29139 HRS ACCUM 0.25 G160M 1296 STEP-PATT=5 1 20.0M 10 2 1 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 32.1 HD29139 HRS ACCUM 0.25 G160M 1296 STEP-PATT=5 1 20.0M 10 2 1 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 32.3 WAVE HRS ACCUM SC2 G160M 1550 STEP-PATT=3 1 3.2S 1 CALIB FOR 32.7 NO SLEW SEQ 32.3-32.7 NON- INT ------------------------------------------------------------------------------------------------------------------------------------ 32.7 HD29139 HRS ACCUM 0.25 G160M 1550 STEP-PATT=5 1 20.0M 8 1 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 32.8 HD29139 HRS ACCUM 0.25 G160M 1550 STEP-PATT=5 2 20.0M 8 1 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 34.3 WAVE HRS ACCUM SC2 G160M 1655 STEP-PATT=3 1 3.2S 1 CALIB FOR 34.7 NO SLEW SEQ 34.3-34.7 NON- INT ------------------------------------------------------------------------------------------------------------------------------------ 34.7 HD29139 HRS ACCUM 0.25 G160M 1655 STEP-PATT=5 1 20.0M 10 3 1 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 34.8 HD29139 HRS ACCUM 0.25 G160M 1655 STEP-PATT=5 1 20.0M 10 3 1 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 5358 [ 8] ------------------------------------------------------------------------------------------------------------------------------------ 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 ------------------------------------------------------------------------------------------------------------------------------------ 37 WAVE HRS ACCUM SC2 G200M 1994 STEP-PATT=3 1 3.2S 1 CALIB FOR 38.0 NO SLEW SEQ 37-38 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 38 HD29139 HRS ACCUM 0.25 G200M 1994 STEP-PATT=5 1 20.0M 4 1 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 39 WAVE HRS ACCUM SC2 G270M 2753 STEP-PATT=3 1 3.2S 1 CALIB FOR 40 NO SLEW SEQ 39-40 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 40 HD29139 HRS ACCUM 0.25 G270M 2753 STEP-PATT=5 1 10.9M 30 6 1 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 53 WAVE HRS ACCUM SC2 ECH-B20 2799.0 STEP-PATT=3 1 3.2S 1 CALIB FOR 54 NO SLEW SEQ 53-54 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 54 HD29139 HRS ACCUM 0.25 ECH-B20 2799.0 STEP-PATT=7 1 14.51M 8 1 FP-SPLIT=STD ------------------------------------------------------------------------------------------------------------------------------------ 60 WAVE HRS ACCUM SC2 G270M 2345.0 STEP-PATT=3 1 3.2S 1 CALIB FOR 61 NO SLEW SEQ 60-61 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ 61 HD29139 HRS ACCUM 0.25 G270M 2345.0 STEP-PATT=5 1 20.0M 35 5 1 FP-SPLIT=STD Comments: SECOND C II EXPOSURE (2 OF 2) ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 5358 [ 9] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAKUP ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE=5 BRIGHT=RETURN STEP-PATT=3 STEP-PATT=5 FP-SPLIT=STD STEP-PATT=7 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 6.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category COOL STARS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category STELLAR ATMOSPHERES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 4 / 10-61; ONBOARD ACQ FOR 11; SEQ 10-61 NO GAP ONBOARD ACQ FOR 12-61 CALIB FOR 13 NO SLEW; SEQ 12-13 NON-INT CALIB FOR 32 NO SLEW; SEQ 31-32 NON-INT CALIB FOR 32.7 NO SLEW; SEQ 32.3-32.7 NON-INT CALIB FOR 34.7 NO SLEW; SEQ 34.3-34.7 NON-INT CALIB FOR 38.0 NO SLEW; SEQ 37-38 NON-INT CALIB FOR 40 NO SLEW; SEQ 39-40 NON-INT CALIB FOR 54 NO SLEW; SEQ 53-54 NON-INT CALIB FOR 61 NO SLEW; SEQ 60-61 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-A2 G270M G160M G200M ECH-B20 ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD29139 ALPHA-TAU ------------------------------------------------------------------------------------------------------------------------------------