! $Id: 5188,v 4.1 1994/07/27 15:49:10 pepsa Exp $ coverpage: title_1: EARLY RELEASE OBSERVATIONS OF ETA CARINA sci_cat: INTERSTELLAR MEDIUM sci_subcat: CIRCUMSTELLAR MATTER proposal_for: SMC/ERO pi_title: DR. pi_fname: WILLIAM pi_lname: SPARKS pi_inst: STSCI pi_country: USA hours_pri: 2.72 num_pri: 1 wf_pc: Y ! end of coverpage abstract: line_1: This proposal is to assess the high dynamic range and improved contrast line_2: of the refurbished HST by observing the extraordinary nebulosity line_3: surrounding the massive star Eta Carina. ! ! end of abstract general_form_proposers: lname: SPARKS fname: WILLIAM title: DR. inst: STSCI country: USA esa: N ! lname: WESTPHAL fname: JAMES title: DR. mi: A. inst: 1590 country: USA esa: N ! lname: HESTER fname: JEFF title: DR. mi: J. inst: 1220 country: USA esa: N ! lname: LIGHT fname: ROBERT title: DR. mi: M. inst: 1590 country: USA esa: N ! ! end of general_form_proposers block general_form_text: question: 2 section: 1 line_1: The star Eta Carinae is one of the most well studied and fascinating objects in line_2: the sky. The star itself is thought to be one of the most massive stars in the line_3: galaxy, with an estimated mass of perhaps 150 Msun and a luminosity of 10^6.6 line_4: Lsun. In 1841 Eta Car underwent a tremendous outburst, during which it reached line_5: a magnitude of -1, making it the second brightest star in the sky behind line_6: Sirius. Since that time the visual magnitude of the star has dropped to around line_7: 6 as a result of extinction from a massive dusty shell. However, at 10microns line_8: Eta Car remains the brightest object in the sky outside of our solar system. line_10: Today, Eta Car is surrounded by a rapidly expanding shell of material which was line_11: ejected during the last century's outburst. This expanding nebula, referred to line_12: as the ``homunculus'' or ``little man,'' was the target of observations with line_13: the WF/PC-I. The Homunculus is approximately 12" x 17" in size, and is line_14: expanding at a velocity of about 1200 km/s. The structure of the nebula as line_15: revealed by the WF/PC image is truly remarkable, showing a very sharply bounded line_16: shell which breaks up into many unresolved knots and filaments. The real line_17: surprise in the WF/PC-I observations was in the outer portion of the nebula, line_18: however. Here, what was previously thought to be simply an especially rapidly line_19: moving clump of ejecta turned out instead to be a jet of material emanating line_20: from the star and the bow shock formed where this jet interacts with line_21: surrounding interstellar material. The presence of this jet in what is line_22: generally assumed to be the equatorial plane of the object raises fundamental line_23: questions about the nature of the outflow. ! question: 2 section: 2 line_1: Perhaps the most surprising aspect of the HST observations of Eta Car is the line_2: presence of a series of 7 regularly spaced striations across the face of the line_3: bow shock. These have the appearance of the rungs of a ladder, and are line_4: perpendicular to the local radius vector from the star. These features are a line_5: puzzle. No good explanation for them exists. To be frank, no ``not so good'' line_6: explanation for them exists. A number of theorists who have looked at them line_7: want desperately to believe that they are not real, and hope to ascribe them to line_8: some difficulty with the data. line_10: Observations of Eta Car with the WFPC-2 would be a good candidate for the ERO line_11: program for a number of reasons. Initially, it will be a spectacular image -- line_12: well superior to the WF/PC-I image. With a very bright star in the center of line_13: the object and interest in low contrast features throughout the object, the line_14: nebula around Eta Car pushes even the capabilities of the WFPC-2 for dynamic line_15: range. There will without question be many interesting features of the object line_16: that are seen with WFPC-2 that were not apparent in the WF/PC-I data. line_17: Secondly, a WFPC-2 image should immediately clear up the controversy line_18: surrounding the reality of features seen in the WF/PC-I data. If these line_19: features are seen in WFPC-2 images, then this confirms an interesting and line_20: unexpected result from HST -- good news. If these features are not seen, then line_21: it points out the sort of difficulties that complicated interpretation of line_22: pre-fix HST data -- justification for the repair mission. ! question: 2 section: 3 line_1: Finally, the Eta Car system is evolving very rapidly. Even from the ground line_2: changes are seen in the structure of the object over time scales of a few line_3: years. Significant changes should be apparent in Eta Car at HST resolution line_4: over the time between the original images and the WFPC-2 images. Comparison of line_5: these data sets will answer many fundamental questions about the nature of the line_6: system. For example, non-radial motions of fragments in the main shell of the line_7: nebula would show that non-radially symmetrical pressure forces have been line_8: important in accelerating the shell over the lifetime of the structure. The line_9: northern jet and bow shock should have changed the most of any observed line_10: structures, and these changes should help to answer questions about the line_11: direction of shock propagation and other data relevant to understanding the line_12: manner in which this part of the system is evolving. Finally, assuming that line_13: the WFPC-2 observations also reveal the peculiar ``rungs'' across the face of line_14: the bow shock, motion or lack thereof of these features (i.e., are they line_15: convecting outward with the rest of the structure or do they appear to be some line_16: sort of standing wave phenomenon?) would provide some clues for what these line_17: features are and what causes them. ! question: 3 section: 1 line_1: Short description of proposed observations line_2: Place Eta Car in the center of one of the WFC chips. line_3: The nebulosity is strongest in [N II] (F658N). Even from the ground line_4: there are noticeable differences between [N II] and [O III] images, so line_5: these two filters should allow a nice color image to be produced. line_6: The field MUST be oriented so that chip bleeding and diffraction line_7: spikes avoid the region of the jet and the bow shock. line_8: Multiple exposures are required to obtain the overall dynamic range line_9: needed. These will be scaled and combined in similar fashion to the line_10: WF/PC-I images. If time is a major concern in these images, the line_11: CR-splits could be removed, but only at some risk of confusion with line_12: sharp features in the homunculus. ! question: 4 section: 1 line_1: (a) Justify the need for the capabilities if HST. line_7: (b) Justify the amount of exposure time. ! question: 5 section: 1 line_1: Special Scheduling line_2: The orientation must be constrained to avoid bleeding through line_3: regions of special interest, specifically the jet region. Four line_4: pointing / orientation combinations are specified to aid in scheduling line_5: the observations. ! question: 6 section: 1 line_1: Special calibrations line_3: PSF ! question: 7 section: 1 line_1: Data reduction and analysis line_3: The data will be rapidly processed for early assessment of the HST recovery. ! !end of general form text general_form_address: lname: Sparks fname: William title: Dr. category: PI inst: STScI addr_1: 3700 San Martin city: BALTIMORE state: MD zip: 21218 country: USA phone: 410-338-4827 telex: 410-338-1592 from_date: 21-MAR-88 to_date: 21-MAR-98 ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: ETA-CAR descr_1: A, 926 pos_1: RA= 10H 43M 06.87S +/-0.1", pos_2: DEC= -59D 25' 16" +/-0.1" equinox: 1950 comment_1: ERUPTIVE/VARIABLE STAR ! targnum: 2 name_1: PSF-ETA-CAR descr_1: A, 704 pos_1: RA= 10H 18M 38.60S +/- 0.1", pos_2: DEC= -56D 06' 34.269" +/- 0.1" equinox: 2000 comment_1: PSF STAR (SAO 237902) comment_2: F8 V=6.1 ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 sequence_1: DEFINE sequence_2: ECARSEQ targname: ETA-CAR config: WFPC2 opmode: IMAGE aperture: # sp_element: F658N num_exp: 2 time_per_exp: 0.11S priority: 1 param_1: ATD-GAIN=15 req_1: SAME POS FOR 2.000-9.000 AS 1.000 ; req_2: SAME ORIENT FOR 2.000-9.000 AS 1.000 ; req_3: NON-INT / 1.000; req_4: SEQ 2.000-3.000 NO GAP ; req_5: GROUP 2.000-11.000 WITHIN 3D ; req_6: CYCLE 4/1-14; ! linenum: 2.000 sequence_1: DEFINE sequence_2: ECARSEQ targname: ETA-CAR config: WFPC2 opmode: IMAGE aperture: # sp_element: F658N num_exp: 2 time_per_exp: 4S priority: 1 param_3: CLOCKS=YES, param_4: ATD-GAIN=7 req_1: NON-INT / 2.000; ! linenum: 3.000 sequence_1: DEFINE sequence_2: ECARSEQ targname: ETA-CAR config: WFPC2 opmode: IMAGE aperture: # sp_element: F658N num_exp: 2 time_per_exp: 200S priority: 1 param_3: CLOCKS=YES, param_4: ATD-GAIN=7 req_1: NON-INT / 2.000; ! linenum: 4.000 sequence_1: DEFINE sequence_2: ECARSEQ targname: ETA-CAR config: WFPC2 opmode: IMAGE aperture: # sp_element: F375N num_exp: 2 time_per_exp: 0.11S priority: 1 param_3: ATD-GAIN=15 req_1: SEQ 4.0-6.0 NO GAP ; req_2: NON-INT / 4.000; ! linenum: 5.000 sequence_1: DEFINE sequence_2: ECARSEQ targname: ETA-CAR config: WFPC2 opmode: IMAGE aperture: # sp_element: F375N num_exp: 2 time_per_exp: 4S priority: 1 param_3: CLOCKS=YES, param_4: ATD-GAIN=7 req_1: NON-INT / 5.000; ! linenum: 6.000 sequence_1: DEFINE sequence_2: ECARSEQ targname: ETA-CAR config: WFPC2 opmode: IMAGE aperture: # sp_element: F375N num_exp: 2 time_per_exp: 200S priority: 1 param_3: CLOCKS=YES, param_4: ATD-GAIN=7 req_1: NON-INT / 6.000; ! linenum: 7.000 sequence_1: DEFINE sequence_2: ECARSEQ targname: ETA-CAR config: WFPC2 opmode: IMAGE aperture: # sp_element: F502N num_exp: 2 time_per_exp: 0.11S priority: 1 param_3: ATD-GAIN=15 req_1: SEQ 7.0-9.0 NO GAP ; req_2: NON-INT / 7.0; ! linenum: 8.000 sequence_1: DEFINE sequence_2: ECARSEQ targname: ETA-CAR config: WFPC2 opmode: IMAGE aperture: # sp_element: F502N num_exp: 2 time_per_exp: 4S priority: 1 param_3: CLOCKS=YES, param_4: ATD-GAIN=7 req_1: NON-INT / 8.000; ! linenum: 9.000 sequence_1: DEFINE sequence_2: ECARSEQ targname: ETA-CAR config: WFPC2 opmode: IMAGE aperture: # sp_element: F502N num_exp: 2 time_per_exp: 200S priority: 1 param_3: CLOCKS=YES, param_4: ATD-GAIN=7 req_1: NON-INT / 9.000; ! linenum: 10.000 sequence_1: DEFINE sequence_2: ECARSEQ targname: PSF-ETA-CAR config: WFPC2 opmode: IMAGE aperture: # sp_element: F658N num_exp: 2 time_per_exp: 0.11S priority: 1 req_1: SEQ 10.0-11.0 NO GAP ; req_2: NON-INT / 10.0; comment_1: PSF STAR TO MAP OUTER PARTS OF comment_2: ETA CARINAE PSF. THIS STAR comment_3: MUST BE IN THE SAME POSITION ON comment_4: THE SAME CHIP AS THE ETA CAR comment_5: EXPOSURE, **BUT DOES NOT HAVE TO comment_6: FULFILL THE ORIENT REQUIREMENT**. ! linenum: 11.000 sequence_1: DEFINE sequence_2: ECARSEQ targname: PSF-ETA-CAR config: WFPC2 opmode: IMAGE aperture: # sp_element: F658N num_exp: 2 time_per_exp: 200S priority: 1 param_3: CLOCKS=YES, param_4: ATD-GAIN=7 req_1: NON-INT /11.000; comment_1: PSF STAR SHOULD REALLY BE comment_2: OBSERVED IN F502N AND F375N comment_3: AS WELL... ! linenum: 11.500 sequence_1: USE sequence_2: ECARSEQ aperture: WF2-FIX req_1: SELECT 1 OF 11.5 OR 12 OR 13 OR 14 ; req_2: ORIENT 350D +/- 32D ; req_3: COND IF ORIENTATION CAN BE SCHEDULED; comment_1: PLACE ETA CARINAE IN THE CENTER comment_2: OF THE WFC CHIP WHICH BLEEDS TO THE comment_3: SOUTH OF THE STAR. ORIENTATION comment_4: IS CONSTRAINED SO THAT BLEEDING comment_5: DOES NOT AFFECT THE NN "JET." comment_6: SELECT SCHEDULEABLE ROLL ANGLE. ! linenum: 12.000 sequence_1: USE sequence_2: ECARSEQ aperture: WF2-FIX req_1: ORIENT 217D +/- 8D ; req_2: COND IF ORIENTATION CAN BE SCHEDULED; ! linenum: 13.000 sequence_1: USE sequence_2: ECARSEQ aperture: WF3-FIX req_1: ORIENT 127D +/- 8D ; req_2: COND IF ORIENTATION CAN BE SCHEDULED; ! linenum: 14.000 sequence_1: USE sequence_2: ECARSEQ aperture: WF4-FIX req_1: ORIENT 37D +/- 8D ; req_2: COND IF ORIENTATION CAN BE SCHEDULED; ! ! end of exposure logsheet ! No scan data records found