! Proposal 5838, submission 2 ! PI: Kailash Sahu ! Received Mon Oct 23 17:55:34 EDT 1995 ! From: ksahu@stsci.edu ! Proposal 5838, submission 1 ! PI: Kailash Sahu ! Received Sat Apr 1 15:27:23 EST 1995 ! From: ksahu@eso.org ! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 5838,v 4.1 1995/11/22 16:44:56 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: Andy Lubenow ! Phone: 410 338-4928 , E-mail: lubenow@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Name of Phase I Proposal: sahu-959.prop ! Date generated: Fri Dec 16 15:10:31 EST 1994 ! Proposal_Information ! Section 4 Title: The rapidly-evolving hypergiant IRC +10420 Proposal_Category: GO Scientific_Category: Cool Stars Cycle: 5 Investigators PI_name: Kailash Sahu PI_Institution: Space Telescope Science Institute CoI_Name: Rene Oudmaijer CoI_Institution: Kapteyn Laboratory Contact: N CoI_Name: Howard Bond CoI_Institution: Space Telescope Science Institute Contact: N ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) We propose to undertake a detailed study of the circumstellar envelope of the peculiar F hypergiant IRC +10420, which is a unique object, caught in the short transition phase between the red supergiant and the Wolf-Rayet stage. By performing high spatial resolution imaging in a number of emission lines that probe several parts of the wind we aim to determine the shape and the kinematic structure of the circumstellar envelope. In particular we wish to to investigate whether the geometry of the wind is disc-like or bipolar. The observations will help understanding the change in geometry of the circumstellar envelope as stars evolve from the Red Supergiant Stage to the Wolf-Rayet phase. Questions ! Free format text (please update) Observing_Description: The planetary camera images will enable us to identify the spatial extent and structure of the object. To distinguish between the disc and the bi-polar geometry, images need to be taken in different filters as follows: (i) to probe the outflow very close to the star, we will use the HBeta (filter F487N) and PDelta (filter F1042M) lines, (ii) to probe the larger ionised region, we will use the HAlpha (filter F656N), and (iii) to probe the ``lukewarm", lower density part of the envelope, we will use the OI 6300 Angstrom \ line (filter F631N). For continuum observations, we propose broad band images in UBVRI (filters F336W, F439W, F555W, F675W, F791W), to investigate the possible effects of scattering by circumstellar dust with wavelength. We emphasize that this is a bright source with most of the flux concentrated towards the central region, and faint structure extending up to about 2 arc sec. So the integration times are invariably very short, but it is important to take exposures in various filters which probe different parts of the structure. The object is fairly red, B=13, V=11, R=9 and I=8th magnitude. The observed line fluxes of IRC+10420 (Oudmaijer et al. 1994) were used to determine exposure times. As an example, we consider the HAlpha line, for which we propose to use the F656N filter. This filter has a system throughput of 12\ flux from IRC+10420 at HAlpha line is 0.9 * 10^-11 erg cm^-2 s^-1 and the continuum expected is 0.95 * 10^-11 erg cm^-2 s^-1; thus the total expected flux in the filter F656N is ~ 1.85 * 10^-11 erg cm^-2 s^-1. The number of quanta per unit of energy at this wavelength is ~ 3 * 10^11 photons erg^-1. The effective telescope collecting area is 3.9 * 10^4 cm^2. Multiplying all of these together and then dividing by gain of the CCD (14 e^-/DN), we get a total of 15.000 counts over the whole area of the object. Since a significant part of this flux is concentrated to the central region, we would need an integration time of 2 sec which, because of the very high signal to noise, will enable us to see the expected extended structure, without any saturation effects at the central region. The integration times for the other filters vary between 0.11 sec for the F675W filter to 2.5 min for the F336W filter. We aim for high signal-to-noise and propose to obtain 9 exposures in total, in various filters as mentioned above. Including overhead and detector read-out these observations will take slightly less than 1 orbit in total. Thus we request a total spacecraft time of 1 orbit., Real_Time_Justification: No Special Requirements We plan to continue to monitor IRC +10420 using ground-based telescopes. Calibration_Justification: No Special Requirements ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: IRC+10420 Alternate_Names: BD+11D3841 Description: STAR Position:RA=19H 26M 48.08S +/-0.1S, DEC=+11D 21' 16.8" +/- 0.2" ! PLATE-ID= ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox:2000.0 RV_or_Z:V=60 RA_PM: 0 ! Units are seconds of time per year Dec_PM: 0 ! Units are seconds of arc per year Epoch: 1950.0 Annual_Parallax:0 Flux: V=11+/-0.5, B-V=2+/-0.3 ! Include at least V and B-V Comments: ! 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 ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling ! PCS MODE [Fine | Gyro] ! GUIDing TOLerance ! ORIENTation TO ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! AFTER [BY [TO ]] ! AFTER ! BEFORE ! BETWEEN AND ! GROUP WITHIN