! Proposal 6808, submission 1 ! PI: Andrea K. Dupree ! Received Fri Mar 8 16:31:33 EST 1996 ! From: gillil@stsci.edu ! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! $Id: 6808,v 3.1 1996/03/08 22:02:57 pepsa Exp $ ! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! $Id: 6808,v 3.1 1996/03/08 22:02:57 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Lucas ! Phone: 410-338-4716 , E-mail: lucas@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Name of Phase I Proposal: archive-1075.dupree.prop ! Date generated: Fri Dec 22 16:42:13 EST 1995 ! Proposal_Information ! Section 4 Title: Capella: Separating the Giants Proposal_Category: GO Scientific_Category: COOL STARS Cycle: 6 Investigators PI_name: Andrea K. Dupree PI_Institution: Smithsonian Astrophysical Observatory CoI_Name: Nancy S. Brickhouse CoI_Institution: Smithsonian Astrophysical Observatory Contact: ! Y or N (designate at most one contact) CoI_Name: Ronald L. Gilliland CoI_Institution: Space Telescope Science Institute Contact: Y ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) The bright giants in the Capella system form a test of the evolution of stellar magnetic activity: the primary star is a clump giant in the helium burning phase; the secondary star is a rapidly rotating star in the Hertzsprung Gap. Optical, ultraviolet, and EUV studies give differing and puzzling results as to the assignment of Capella's prodigious radiative output. We propose a unique use of the objective prism on the FOC in order to separate the two components, firmly identify the sources of emission, and answer fundamental questions about the presence and evolution of stellar chromospheres and coronae. Questions ! Free format text (please update) Observing_Description: The observations will be made at elongation when the stars are separated by their maximum amount (56.5 mas; Hummel Etal\ 1994). This occurs approximately every half-period or 52 days. We will select an appropriate time so that the major axis of the apparent orbit is perpendicular to the dispersion of the prisms. The first orbit will be an interactive Bright Target acquisition followed by direct imaging in the near ultraviolet continuum to define the stellar positions and separations. Although we expect the atmospheres to be extended, and hence appear larger in the ultraviolet, they will still have an apparent size less than or comparable to a pixel (14 mas) (If the ultraviolet continuum disk is twice the size of the star in the visible, the disk of the primary is 17.0 mas, and of the secondary 12.8 mas.) We plan to use the Objective Prisms on the FOC in order to obtain spectra of the regions \gl\gl1235--1425; \gl\gl1525-1675; and the 2800Angstrom\ region. The setup and exposures amount to one orbit for each of the 3 bands. We will use various crossed filter configurations to acquire our principal lines of interest (see Table 2), and to exclude the red spectral region. The major neutral density filters are located on the same filter wheel as the prisms, and so a mix of crossed wide and medium band filters will need to be set up. We are not concerned about the absolute calibration of the emission line flux since that has been well studied, but we wish to estimate the relative flux in each line from the two stars. A serious consideration is the dynamic range of the detectors, and the unknown relative contribution of the two giants. We will evaluate filter combinations and exposures at the top of the dynamic range for the total flux from the system which is well known; individual fluxes will be less. To isolate the important He II \gl1640 transition, two filter configurations will likely be needed, although it may be that two prism configurations will also be necessary. The FOC team has obtained prism spectra of standard stars, so those should serve to define the point spread function ( cf. Jakobsen Etal\ 1993; Paresce Etal\ 1995). We note that we detected a bug in the prism simulator program for the FOC when applied to line spectra in the far ultraviolet, so that detailed computations of many crossed filter configurations were not possible for this proposal. We have had discussions with the FOC team at the STScI and the computer program could not be modified in time to meet the Cycle 6 deadline for proposals. We are confident however that the spectra can be obtained as proposed in the requested time. =2pc centerline Table 2: Ultraviolet Fluxes from the Capella System def width 16.5 truecm # & # & # & # noalign 2pt noalign 4 pt Emission& Wavelength& multispan2 Observed Flux at Earth noalign\kern -2pt Feature&(AA)&(10^-12 erg\ cm^-2 s^- 1)&(photon\ cm^-2 s^-1) noalign 2pt noalign\kern 2pt N V& 1240. &8.8&0.55 O I& 1305. &31.4& 2.06 C II& 1335. &23.7&1.59 Si IV& 1400.& 23.9&1.68 C IV& 1549.& 41.0&3.20 He II& 1640.&6.7&0.55 Mg II&2800.&1400.&197. noalign\kern 2pt noalign 2pt \medskip ^\dagger Fluxes from from Linsky Etal\ 1995 and Ayres and Linsky 1980. Real_Time_Justification: Bright Target Acquisition Procedure for the FOC will be used. A real-time acquisition will be necessary. The brightness of Capella (V=0.08), and our desire to use the 128x128 IMAGE mode force real-time contacts to: 1) verify filter positions before a slew to the target can be made, and 2) perform an interactive acquisition to center the target for the 1.8'' square 128x128 IMAGE field. This program is Time-Critical because an observing date (~ +/- 3 days) must maximize the separation of the stars. We have time awarded on EUVE through 1995 to continue monitoring Capella; we are proposing for additional simultaneous time on ASCA and EUVE in order to better define the emission measure at high temperatures, and to determine the coronal abundances in the system. Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: HD34029 Alternate_Names: CAPELLA, GSC3358-03141 Description: STAR, G III-I Position: RA = 05H 16M 41.35S +/- 0.01S, DEC = 45D 59' 52.9" +/- 0.1" ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox: J2000 RV_or_Z: RA_PM: +0.0073 ! Units are seconds of time per year Dec_PM: -0.425 ! Units are seconds of arc per year Epoch: 2000.0 Annual_Parallax: 0.075 Flux: V = 0.08 +/- 0.01, B-V = 0.80 +/- 0.01, F-LINE(1335) = 21 +/- 2 E-12, F-LINE(1356) = 8 +/- 1 E-12, F-LINE(1394) = 15 +/- 1 E-12, F-LINE(1486) = 18 +/- 5 E-13, F-LINE(1640) = 10 +/- 1 E-12 Comments: Coords, PM from Hipparcos INCA (as given in GO-5886) ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number: 1 Visit_Requirements: ! Section 7.1 PERIOD 52.011D AND ZERO-PHASE JD2447502.44 ORIENT 171D TO 177D SCHED 90% ! ORIENT 342D to 348D ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling ! PCS MODE [Fine | Gyro] ! GUIDing TOLerance ! DROP TO GYRO IF NECESSARY [NO REACQuisition] ! ORIENTation TO ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! SCHEDulability ! AFTER [BY [TO ]] ! AFTER ! BEFORE ! BETWEEN AND ! GROUP WITHIN