J/PASP/110/1012 New double stars from HST (Schneider+, 1998)
Duplicity in Hubble Space Telescope Guide Stars:
Fine Guidance Sensor serendipitous survey results.
Schneider G., Hershey J.L., Wenz M.T.
<Publ. Astron. Soc. Pac. 110, 1012 (1998)>
=1998PASP..110.1012S 1998PASP..110.1012S
ADC_Keywords: Stars, double and multiple ; Interferometry
Mission_Name: HST
Abstract:
Data from the Hubble Space Telescope (HST) Fine Guidance Sensor (FGS)
interferometers, covering 22 months of guide-star acquisition
operations, have been analyzed for evidence of stellar duplicity. The
data comprise a survey of observed guide stars, all of which are taken
from the HST Guide Star Catalog, ranging in magnitude from 9 to 14.
The survey results cover a parameter space for the newly found
doubles, for the fainter stars, which are of smaller limiting angular
separations than in any previous surveys. The normal HST engineering
telemetry data from 13,979 acquisitions on 4882 stars have been
processed. The FGS guidance data can reveal duplicity with separations
ranging from approximately 30mas, for the brighter stars, with small
magnitude differences, up to the neighborhood of 500mas, and in some
cases to 1000mas. The fraction of guide stars indicating duplicity is
a function of the statistical criteria used but is over 5% at a very
high level of confidence. It is possible that if some of the brighter
and closer pairs could be identified as nearby, then their orbital
motions would be rapid enough to allow a mass and distance
determination on a timescale of a decade if followed with ground-based
interferometric and spectroscopic instruments. A brief catalog of
doubles is given, nearly all of which are of certain duplicity.
Information for accessing on-line catalogs of large numbers of stars
with lesser, but nevertheless strong, probabilities of duplicity and
also for the solutions for duplicity from all acquisitions is
provided.
Description:
The table2 contains erroneous coordinates, especially for declination
(up to 1 arcmin). This mismatch is very annoying for automated search
procedures. Corrected positions and additional 2MASS identifications
have been added to original table2.
Corrections from Saulius Raudeliunas [Vilnius University Obs.],
25 February 2014.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 255 278 *Selected doubles from HST acquisition data,
plus corrections from Saulius Raudeliunas
names.dat 22 2348 List of observed HST guide stars searched for
duplicity
acquis.dat 204 16164 *Planned acquisition description
doubles.dat 85 63515 *Double star solutions
otab2.dat 120 278 Original table 2 (before 2014 corrections)
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Note on table2.dat : Coordinates have been corrected by Saulius Raudeliunas.
Note on acquis.dat, doubles.dat :
Copied at http://nicmosis.as.arizona.edu:8000/pub/gsdoubles.html
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See also:
http://nicmosis.as.arizona.edu:8000/pub/gsdoubles.html :
Catalog of HST Guide Star acquisitions serendipitous duplicity survey
I/220 : The HST Guide Star Catalog, Version 1.1 (Lasker+ 1992)
I/254 : The HST Guide Star Catalog, Version 1.2 (Lasker+ 1996)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAOh Original Right ascension, GSC position (J2000.0)
4- 5 I2 min RAOm Original Right ascension, GSC position (J2000.0)
7- 10 F4.1 s RAOs Original Right ascension, GSC position (J2000.0)
12 A1 --- DEO- Original Declination sign (J2000.0)
13- 14 I2 deg DEOd Original Declination, GSC position (J2000.0)
16- 17 I2 arcmin DEOm Original Declination, GSC position (J2000.0)
19- 20 I2 arcsec DEOs Original Declination, GSC position (J2000.0)
22- 31 A10 --- GSC Guide Star Catalog number (G1)
34- 37 I4 yr Epoch.Y [1996/1997] Year of the epoch of observation
39- 41 I3 d Epoch.D Day of the epoch of observation
43- 44 I2 h Epoch.h Hour of the epoch of observation
45 A1 --- --- [:]
46- 47 I2 min Epoch.m Minute of the epoch of observation
49- 53 F5.2 mag mag Magnitude from the GSC (1)
55- 56 A2 --- XY [XY ] Symbol for the FGS coordinate of
duplicity detection (2)
58- 63 F6.1 mas Sep Separation (3)
65- 69 F5.1 deg PA Position angle (4)
71- 74 F4.2 mag Dmag Magnitude difference between the components as
computed from the ratio of the amplitudes of
the component S-curves (5)
76- 79 F4.2 mag e_mag ? Standard error of the observations that
formed the delta magnitude mean if more
than one observation
81- 82 I2 --- o_SepX [1/39]? Number of observations in the X
coordinate combined to form the entries in
the table line
84- 90 F7.1 mas SepX ? Mean of the X separations, or the X separation
if only one observation
92- 95 F4.1 mas s_SepX ? Standard error of the observations that formed
the X mean
97-100 F4.1 mas e_SepX ? Error of the mean separation X
102-103 I2 --- o_SepY [1/16]? Number of observations in the Y
coordinate combined to form the entries in
the table line
105-110 F6.1 mas SepY ? Mean of the Y separations, or the Y separation
if only one observation
112-115 F4.1 mas s_SepY ? Standard error of the observations that formed
the Y mean
117-120 F4.1 mas e_SepY ? Error of the mean separation Y
122-151 A30 --- SName Simbad name (as of 25 February 2014)
when empty, field GSC or 2MASS should be
used as main with coordinates from GSC 1.2 (6)
153 A1 --- n_SName [OMAP] type of Simbad identifier (6) (7)
155-159 A5 --- --- [GSC 0]
160-169 A10 --- GSC1.2 GSC 1.2 identifier (6)
171-186 A16 --- 2MASS 2MASS identifier without prefix "2MASS J" (6)
188-189 I2 h RAh Right ascension (J2000) from GSC 1.2 (6)
191-192 I2 min RAm Right ascension (J2000) from GSC 1.2 (6)
194-197 F4.1 s RAs Right ascension (J2000) from GSC 1.2 (6)
199 A1 --- DE- Declination sign from GSC 1.2 (6)
200-201 I2 deg DEd Declination (J2000) from GSC 1.2 (6)
203-204 I2 arcmin DEm Declination (J2000) from GSC 1.2 (6)
206-207 I2 arcsec DEs [0/60] Declination (J2000) from GSC 1.2 (6)
209-231 A23 --- Child1 GSC 1.2 identifier (6)
233-255 A23 --- Child2 GSC 1.2 identifier (6)
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Note (1): Photographic V in northern hemisphere, J (blue) in southern
hemisphere; see GSC references (I/220)
Note (2): The symbols are:
X = X-only duplicity
Y = Y-only duplicity
XY = duplicity in both X and Y
Note (3): Separation is:
* For a single coordinate, the separation is only the projection of the
separation of the double onto the FGS coordinate of observation.
* For a two-coordinate observation, it is the angular separation of
the components. The scale errors of the separations are estimated to
be at the level of a few parts per thousand.
Note (4): position angle is:
* For one-coordinate observations, it is the position angle (equatorial
coordinates) of the FGS coordinate at the time of observation (0-180°).
* For a two-coordinate observation, it is the traditional double-star
position angle, the angle from North to East of the fainter component
relative to the brighter component.
Note (5): The bandpass of the FGSs in guidance is centered near the V
photometric band but spans spectra that range from the U to the R
bands, the mid-3000s to 7000s in Angstrom (Å) units.
Note (6): Corrections from Saulius Raudeliunas [Vilnius University Obs.],
25 February 2014.
Note (7): Corrected positions (column 'n_SName') flag as follows:
O = current Simbad identifier is Ok
M = this Simbad identifier should be kept as main, GSC should be
fused with it
A = additional TYC identification should be added to Simbad as main,
GSC should be fused with it
P = This entry must be a parent object for two childs,
coordinates must be used from GSC 1.2 catalog
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Byte-by-byte Description of file: names.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Filename Source catalog file containing entry
13- 22 A10 --- GSC Guide star catalog ID number (G1)
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Byte-by-byte Description of file: acquis.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Filename Source catalog file containing entry
13- 22 A10 --- GSC Guide star catalog ID number (G1)
24- 32 F9.5 deg RAdeg J2000.0 GS right ascension
34- 42 F9.5 deg DEdeg J2000.0 GS declination
44- 52 F9.5 deg Roll Spacecraft roll angle (360 - Orient)
54- 62 F9.5 deg Sunangle Angular distance of V1 axis to sun
64- 68 F5.2 mag OBmag Observed magnitude in FGS instrumental system
70- 74 F5.2 mag CTmag Magnitude in guide star catalog
76- 80 A5 --- Filtr [PUPIL] Filter used in FGS for acquisition
82- 84 A3 --- --- [FES]
85- 86 I2 ms TM [25/50] Fine error sensor averaging time
88 I1 --- FGS [1/3] FGS interferometer number (1)
90 I1 --- Acq [1/3] Acquisition type (2)
92- 99 A8 --- CPName Guiding scenario (PCS logic):
PQ3AC1, PQ3M1X1, or PCPREACQ
101-104 I4 --- LCT Low (PMT) count threshold for star detection
106-110 F5.2 arcsec WdlX Walk-down length along X axis
112-116 F5.2 arcsec WdlY Wald-down length along Y axis
118-126 F9.5 deg RAV1deg RA J2000.0 of S/C V1 axis
128-136 F9.5 deg DEV1deg DEC J2000.0 of S/C V1 axis
138-144 F7.5 --- K1X FGE X-axis interferometer coefficient
146-152 F7.5 --- K1Y FGE Y-axis interferometer coefficient
154-160 F7.5 --- K3X FGE X-axis Q-signal limit
162-168 F7.5 --- K3Y FGE Y-axis Q-signal limit
170 I1 --- PP [0/1] Planetary Parallax (S/C rate)
correction, 0 = off, 1 = on
172-179 A8 --- RefCurve Reference S-curve used in fitting process
181-184 I4 arcsec PicX Predicted FGS X coordinate of star
186-189 I4 arcsec PicY Predicted FGS Y coordinate of star
191-194 I4 yr Epoch.Y Planned U.T. of acquisition start
195 A1 --- --- [.]
196-198 I3 d Epoch.D [0/365] Planned U.T. of acquisition start
199 A1 --- --- [:]
200-201 I2 h Epoch.h [0/24] Planned U.T. of acquisition start
202 A1 --- --- [:]
203-204 I2 min Epoch.m [0/60] Planned U.T. of acquisition start
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Note (1): For 1, FGS1 replacement by FGS1R on 1997 February, Servicing Mission
Note (2): Acquisition type (see sections 2, 3.2 and 3.3 of paper):
1 = Double-star fitting for FGS in lock case (2-star FL)
2 = Double-star fitting for FGS in no-lock case (2-star CT)
3 = One-star fitting for FGS in lock case (1-star FL)
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Byte-by-byte Description of file: doubles.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Filename Source catalog file containing entry
13 A1 --- n_Filename [CDEF] Index for the different solutions
15- 18 A4 --- Code Type of fitting process/solution (1)
20- 28 F9.1 mas Null1 Relative position of star-1 X or Y null line
30- 38 F9.1 mas Null2 Relative position of star-2 X or Y null line
40- 43 F4.2 --- B1 Star-1 amplitude normalized to reference S-curve
45- 48 F4.2 --- B2 Star-2 amplitude normalized to reference S-curve
51- 58 F8.1 mas Sep [-104/] Separation of stars
60- 64 F5.2 mag Dmag Magnitude difference between the components as
computed from the ratio of the amplitudes of
the component S-curves (2)
66- 69 F4.1 mas e_Null1 1-σ error in star-1 null line position
71- 74 F4.1 mas e_Null2 1-σ error in star-2 null line position
75- 79 F5.2 --- e_B1 ? 1-σ error in star-1 to reference
amplitude ratio
80- 84 F5.2 --- e_B2 ? 1-σ error in star-2 to reference
amplitude ratio
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Note (1): Code is made of 4 characters:
Char 1: S/D for Single/Double
Char 2: X/Y indicates which axis of interferometer
Char 3: L/N for Lock/Nolock
Char 4: W/C for Wide/Close solution
Note (2): The bandpass of the FGSs in guidance is centered near the V
photometric band but spans spectra that range from the U to the R
bands, the mid-3000s to 7000s in angstrom units.
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Byte-by-byte Description of file: otab2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Right ascension, GSC position (J2000.0)
4- 5 I2 min RAm Right ascension, GSC position (J2000.0)
7- 10 F4.1 s RAs Right ascension, GSC position (J2000.0)
12 A1 --- DE- Declination sign (J2000.0)
13- 14 I2 deg DEd Declination, GSC position (J2000.0)
16- 17 I2 arcmin DEm Declination, GSC position (J2000.0)
19- 20 I2 arcsec DEs [0/60] Declination, GSC position (J2000.0)
22- 31 A10 --- GSC Guide Star Catalog number (G1)
34- 37 I4 yr Epoch.Y Year of the epoch of observation
39- 41 I3 d Epoch.D Day of the epoch of observation
43- 44 I2 h Epoch.h Hour of the epoch of observation
45 A1 --- --- [:]
46- 47 I2 min Epoch.m Minute of the epoch of observation
49- 53 F5.2 mag mag Magnitude from the GSC
55- 56 A2 --- XY Symbol for the FGS coordinate of
duplicity detection
58- 63 F6.1 mas Sep Separation
65- 69 F5.1 deg PA Position angle
71- 74 F4.2 mag Dmag Magnitude difference between the components as
computed from the ratio of the amplitudes of
the component S-curves
76- 79 F4.2 mag e_mag ? Standard error of the observations that
formed the delta magnitude mean if more
than one observation
81- 82 I2 --- o_SepX ? Number of observations in the X coordinate
combined to form the entries in the table line
84- 90 F7.1 mas SepX ? Mean of the X separations, or the X separation
if only one observation
92- 95 F4.1 mas s_SepX ? Standard error of the observations that formed
the X mean
97-100 F4.1 mas e_SepX ? Error of the mean separation X
102-103 I2 --- o_SepY ? Number of observations in the Y coordinate
combined to form the entries in the table line
105-110 F6.1 mas SepY ? Mean of the Y separations, or the Y separation
if only one observation
112-115 F4.1 mas s_SepY ? Standard error of the observations that formed
the Y mean
117-120 F4.1 mas e_SepY ? Error of the mean separation Y
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Global Notes:
Note (G1): this column contains either the GSC designation (Cat. I/220)
when the leftmost digit is a 0, or a designation in one of the
"Special Catalogs" when the leftmost digit is a 3 or 4. These "Special
Catalogs" were constructed for calibration targets or for regions of
the sky where the GSC, derived from Schmidt Survey plates, may not
have adequate data.
Acknowledgements: Glenn Schneider
History:
* 13-Dec-2000: on-line version
* 26-Feb-2014: corrections added to table2, from Saulius Raudeliunas,
[Vilnius University Obs.]
(End) James Marcout, Patricia Bauer [CDS] 09-Nov-1998