! $Id: 6661,v 9.1 1996/06/28 18:44:19 pepsa Exp $
Proposal_Information
Title: UV Spectroscopy of face-on accretion disks
Proposal_Category: GO
Scientific_Category: BINARIES AND STAR FORMATION
Cycle: 6
Investigators
PI_Name: Richard Wade
PI_Institution: The Pennsylvania State University
CoI_Name: Marcos Diaz
CoI_Institution: Laboratorio Nacional de Astrofisica, Brazil
Contact:
CoI_Name: Ivan Hubeny
CoI_Institution: NASA/Goddard Space Flight Center
Contact:
CoI_Name: Knox Long
CoI_Institution: Space Telescope Science Institute
Contact:
Abstract:
We will obtain GHRS spectra at ~1 Angstrom\ resolution of
three novalike variables that have low orbital inclinations,
BD-7D3007 (= RW Sex), HD174107 (= V603 Aql), and MV-LYR. The
blending and broadening of absorption lines from the accretion
disk will not be as severe in these objects as in more edge-on
systems, and we expect to see individual lines or blends that
are distinctively characteristic of the varying projected
velocities at different temperatures ( i.e. radii) in the
disk. These aspects of the UV disk spectrum have not
previously been used as a tool to study accretion disk
physics. Comparison of line strengths with our detailed
models will indicate whether it is necessary to consider
irradiated or NLTE disks, and test in a new way whether the
disks are in steady state. The shapes of lines that would be
formed in the inner disk will tell whether the inner disk is
actually present, an important check on observational and
theoretical suggestions that the inner disk is missing in some
cataclysmic variables. The improved understanding and
characterization of the photospheric spectrum will aid in the
analysis of the wind-formed P Cygni lines that are seen in
these objects. We will use grating G140L, covering much of
the mid-UV spectrum with S/N up to 200.
Questions
Observing_Description:
We will observe three low-inclination cataclysmic variables,
BD-7D3007 (=RW Sex), HD174107 (=V603 Aql), and MV-LYR, to
study in detail the line spectrum and kinematically-broadened
line profiles of their accretion disks. These are the
brightest systems with low inclination, for which the orbital
periods are known. We will obtain HRS spectra of each target
using G140L. Table 1 gives basic information about the
orbital period, orbital inclination, visibility window, and
the predicted HRS count rate per diode at 1300 Angstrom
using G140L in the LSA. (This is near the peak continuum rate
for these stars, based on IUE low-dispersion data and the
published sensitivity tables for HRS. For G140L/LSA, one
resolution element ~eq 1.4 diode.)
--------------------------------------------------
begintable begincenter begintabularlrrrrrr multicolumn7c
Basic Data on Proposed Targets ,
Name& V Mag& CV Type & Period & Inclination &
Visibility & Count Rate ,
& & & (hours)& (degrees) &
(minutes) & (s^-1 diode^-1), ,
RW Sex & 10.6 &NL/UX& 5.88& 34& 52& 67,
V603 Aql& 11.7&NA & 3.31& 17& 52& 19,
MV Lyr& 13.3&NL/VY& 3.20& 12& 55& 2.3,
endtabular endcenter caption
Count rate is quoted for 1300 Angstrom using
GHRS +
G140L/LSA. CV types are: NL--Novalike, UX--UX UMa subclass,
VY--VY Scl subclass, NA--slow nova. endtable
---------------------------------------------------
We require high
S/N data throughout much of the mid-UV, to sample lines
formed at a broad range of effective temperatures in the
disks. This requires two wavelength settings using G140L,
covering 1150--1437 Angstrom and 1375--1662
Angstrom. The overlap of 54 Angstrom will be used to monitor
the small
variations in continuum flux level that are expected from one
exposure to the next. In addition to sampling the most
important diagnostic lines we will have a long enough
wavelength baseline to fit simultaneously the overall UV
energy distribution. The strongest lines in the IUE spectra
of these stars are the resonance lines of C IV, Si IV, etc.,
which are partially formed in a wind. They are not directly
useful for studying the disk photosphere; indeed, the disk
photospheric spectrum must be understood before the wind
profiles can be isolated. (The data collected on wind lines
through this proposal will be studied by Co-I Long's postdoc,
C. Knigge.) Our goal is to study the host of much weaker
lines and blends, which make a pseudocontinuum with bumps and
wiggles characteristic of a particular combination of white
dwarf mass, mass accretion rate, and inclination, which will
be different for each target. (See figures for examples of
calculated line depths, often <5%.) For this
reason we seek
a S/N of 200 per diode near 1300 Angstrom and
1520 Angstrom (the latter region includes C I and Si II lines). In other
parts of the spectrum the S/N will be below this by as much
as a factor of 3. Our criterion will allow the confident
detection of narrow structures with ~1-2%
depth. The S/N
goal is basically achievable for our two brighter targets,
using 2 orbits for BD-7D3007 (RW Sex) and 4 orbits for
HD174107 (V603 Aql). For our third target, MV-LYR, we must
settle for S/N ~ 100 (short wavelengths) and 65 (long) in
these regions, obtainable in 5 orbits, which should still
allow a good basic analysis. Although we have listed our
targets in priority order, it is important to study more than
one of the targets, especially since HD174107 and MV-LYR are
more nearly face-on. After target acquisition,
we will fill each visibility period on each target with
observations in both wavelength regions, so as to have interleaved
observations to guard against undetected variability.
Each observing period on a given wavelength setting will
be divided into 108.8 intervals, to further explore the
variability issue. There is an overlap region between
our "red" and "blue" settings. The
estimated total exposure time in the short and long regions
is 600 s + 2220 s for BD-7D3007, 1800 s + 4860 s for
HD174107, and 4700s + 4800 s for MV-LYR. We will use
FP-SPLIT=STD to help achieve the high S/N desired.
Because our original third target, MV-LYR, has gone into an extended
faint state, we are substituting in its place the similar system
BZ-CAM. The overall UV flux is similar but redder, and the exposure
sequence has been modified slightly to compensate. Similar S/N is
expected to result.
Real_Time_Justification:
None.
We will seek contemporaneous visual photometry and
spectroscopy to confirm that our targets are in their normal,
bright states. (Only MV-LYR has ever shown brightness levels
significantly below its normal state, in the visible band,
but these occurrences are quite rare.) These visible
observations are not essential to the successful use of HST
observations, but would possibly enhance interpretations of
the HRS data.
Calibration_Justification:
Additional_Comments:
Fixed_Targets
Target_Number: 1
Target_Name: BD-7D3007
Alternate_Names: GSC5490-556,RW-SEX
Description: STAR,NOVA-LIKE,ACCRETION DISK,INTERACTING BINARY,
Position: RA=10H 19M 56.61S +/- 1",DEC=-08D 41' 56.0" +/- 1.0",PLATE-ID=0185
Equinox: J2000
RV_or_Z:
RA_PM:
Dec_PM:
Epoch:
Annual_Parallax:
Flux:
V = 10.4+/-0.3
F(1300)=3+/-0.5e-12
F(1520)=2.4+/-0.6e-12
Comments: Coordinates from GSC, retrieved by R. Downes.
Target_Number: 2
Target_Name: HD174107
Alternate_Names: GSC0448-423,V603-AQL
Description: STAR,CLASSICAL NOVA,ACCRETION DISK,INTERACTING BINARY,
Position: RA=18H 48M 54.61S +/- 1",DEC=00D 35' 03.0" +/- 1.0",PLATE-ID=050T
Equinox: J2000.
RV_or_Z:
RA_PM: 0.0
Dec_PM: 0.0
Epoch:
Annual_Parallax: 0.0
Flux:
V = 11.7+/-0.2
F(1300)=1.15+/-0.1e-12
F(1520)=7.5+/-1.0e-13
Comments: Coordinates from GSC, retrieved by R. Downes.
Target_Number: 3
Target_Name: BZ-CAM
Alternate_Names:
Description: STAR,NOVA-LIKE,ACCRETION DISK,INTERACTING BINARY,
Position: RA=06H 29M 33.95S +/- 1",DEC=71D 04' 37.1" +/- 1.0",PLATE-ID=00M8
Equinox: J2000
RV_or_Z:
RA_PM:
Dec_PM:
Epoch:
Annual_Parallax:
Flux:
V = 13.0+/-0.5
F(1300)=1.5+/-0.5e-13
F(1520)=1.5+/-0.5e-13
Comments: Coordinates are measured by R. Downes.
UV flux varies somewhat, approx 1-sigma range indicated with error bars.
Solar_System_Targets
Generic_Targets
Scan_Data
Visits
Visit_Number: 01
Visit_Requirements:
BETWEEN 01-May-1996 AND 31-May-1996
On_Hold_Comments:
Visit_Comments: The between requirement is to allow for coordination
with some ground observations in April.
Exposure_Number: 10
Target_Name: BD-7D3007
Config: HRS
Opmode: ACQ
Aperture: 2.0
Sp_Element: MIRROR-N1
Wavelength:
Optional_Parameters: BRIGHT=RETURN,SEARCH-SIZE=3
Number_of_Iterations: 1
Time_Per_Exposure: 9S
Special_Requirements:
ONBOARD ACQ FOR 30-71
Comments: STEP-TIME=1S,expected acq count rate is 2000 per second.
Exposure_Number: 30
Target_Name: BD-7D3007
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 5
Time_Per_Exposure: 108.8S
Special_Requirements:
Comments:
Exposure_Number: 31
Target_Name: BD-7D3007
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 5
Time_Per_Exposure: 108.8S
Special_Requirements:
Comments:
Exposure_Number: 50
Target_Name: BD-7D3007
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 5
Time_Per_Exposure: 108.8S
Special_Requirements:
Comments:
Exposure_Number: 51
Target_Name: BD-7D3007
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 5
Time_Per_Exposure: 108.8S
Special_Requirements:
Comments:
Exposure_Number: 70
Target_Name: BD-7D3007
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 5
Time_Per_Exposure: 108.8S
Special_Requirements:
Comments:
Exposure_Number: 71
Target_Name: BD-7D3007
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 4
Time_Per_Exposure: 108.8S
Special_Requirements:
Comments:
Visit_Number: 02
Visit_Requirements:
On_Hold_Comments:
Visit_Comments:
Exposure_Number: 10
Target_Name: HD174107
Config: HRS
Opmode: ACQ
Aperture: 2.0
Sp_Element: MIRROR-N1
Wavelength:
Optional_Parameters: BRIGHT=RETURN,SEARCH-SIZE=3
Number_of_Iterations: 1
Time_Per_Exposure: 36S
Special_Requirements:
ONBOARD ACQ FOR 20-90
Comments: STEP-TIME=4S, expected acq count rate is 800 per second
Exposure_Number: 20
Target_Name: HD174107
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 5
Time_Per_Exposure: 217.6S
Special_Requirements:
Comments:
Exposure_Number: 30
Target_Name: HD174107
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 5
Time_Per_Exposure: 108.8S
Special_Requirements:
Comments:
Exposure_Number: 40
Target_Name: HD174107
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 6
Time_Per_Exposure: 217.6S
Special_Requirements:
Comments:
Exposure_Number: 50
Target_Name: HD174107
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 6
Time_Per_Exposure: 108.8S
Special_Requirements:
Comments:
Exposure_Number: 60
Target_Name: HD174107
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 6
Time_Per_Exposure: 217.6S
Special_Requirements:
Comments:
Exposure_Number: 70
Target_Name: HD174107
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 6
Time_Per_Exposure: 108.8S
Special_Requirements:
Comments:
Exposure_Number: 80
Target_Name: HD174107
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 7
Time_Per_Exposure: 217.6S
Special_Requirements:
Comments:
Exposure_Number: 90
Target_Name: HD174107
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 6
Time_Per_Exposure: 108.8S
Special_Requirements:
Comments:
Visit_Number: 03
Visit_Requirements:
On_Hold_Comments:
Visit_Comments:
Exposure_Number: 10
Target_Name: BZ-CAM
Config: HRS
Opmode: ACQ
Aperture: 2.0
Sp_Element: MIRROR-N1
Wavelength:
Optional_Parameters: BRIGHT=RETURN,SEARCH-SIZE=3,LOCATE=DEF
Number_of_Iterations: 1
Time_Per_Exposure: 56.25S
Special_Requirements:
ONBOARD ACQ FOR 20-150
Comments: STEP-TIME=6.25S, expected acq count rate is 100 per second
Exposure_Number: 20
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 1
Time_Per_Exposure: 979.2S
Special_Requirements:
Comments:
Exposure_Number: 30
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 2
Time_Per_Exposure: 326.4S
Special_Requirements:
Comments:
Exposure_Number: 40
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 1
Time_Per_Exposure: 979.2S
Special_Requirements:
Comments:
Exposure_Number: 50
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 2
Time_Per_Exposure: 326.4S
Special_Requirements:
Comments:
Exposure_Number: 60
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 1
Time_Per_Exposure: 979.2S
Special_Requirements:
Comments:
Exposure_Number: 70
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 2
Time_Per_Exposure: 326.4S
Special_Requirements:
Comments:
Exposure_Number: 80
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 1
Time_Per_Exposure: 979.2S
Special_Requirements:
Comments:
Exposure_Number: 90
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 2
Time_Per_Exposure: 326.4S
Special_Requirements:
Comments:
Exposure_Number: 100
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 1
Time_Per_Exposure: 979.2S
Special_Requirements:
Comments:
Exposure_Number: 110
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 2
Time_Per_Exposure: 326.4S
Special_Requirements:
Comments:
Exposure_Number: 120
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 1
Time_Per_Exposure: 979.2S
Special_Requirements:
Comments:
Exposure_Number: 130
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 2
Time_Per_Exposure: 326.4S
Special_Requirements:
Comments:
Exposure_Number: 140
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1375-1662
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 1
Time_Per_Exposure: 979.2S
Special_Requirements:
Comments:
Exposure_Number: 150
Target_Name: BZ-CAM
Config: HRS
Opmode: ACCUM
Aperture: 2.0
Sp_Element: G140L
Wavelength: 1150-1437
Optional_Parameters: FP-SPLIT=STD
Number_of_Iterations: 2
Time_Per_Exposure: 326.4S
Special_Requirements:
Comments:
Data_Distribution ! Defaults indicated; change if desired
Medium: 8MM
Blocking_Factor: 10
Ship_To: PI_Address
Ship_Via: UPS
Recipient_Email:
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