J/ApJ/636/1020 kappa Peg astrometry and radial velocities (Muterspaugh+, 2006)
PHASES differential astrometry and iodine cell radial velocities of the κ
Pegasi triple star system.
Muterspaugh M.W., Lane B.F., Konacki M., Wiktorowicz S., Burke B.F.,
Colavita M.M., Kulkarni S.R., Shao M.
<Astrophys. J., 636, 1020-1032 (2006)>
=2006ApJ...636.1020M 2006ApJ...636.1020M
ADC_Keywords: Stars, double and multiple ; Radial velocities
Keywords: astrometry - binaries: close - binaries: visual - stars: distances -
stars: individual (κ Pegasi) - techniques: interferometric
Abstract:
κ Pegasi is a well-known, nearby triple star system. It consists
of a "wide" pair with semimajor axis =235mas, one component of which
is a single-line spectroscopic binary (semimajor axis =2.5mas).
Using high-precision differential astrometry and radial velocity
observations, the masses for all three components are determined and
the relative inclination between the wide and narrow pairs' orbits
is found to be 43.8°±3.0°, just over the threshold for the
three-body Kozai resonance. The system distance is determined to be
34.60±0.21pc and is consistent with trigonometric parallax
measurements.
Description:
κ Pegasi was observed with the Palomar Testbed Interferometer
(PTI) on 52 nights in 2002-2004 using the observing mode.
Objects:
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RA (2000) DE Designation(s)
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21 44 38.7 +25 38 42 kappa pegasi = HD 206901
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 115 52 PHASES data for κ Pegasi
table2.dat 169 455 Previous astrometry measurements
table3.dat 45 32 Keck-HIRES radial velocities
table4.dat 24 10 Previous radial velocity measurements
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See also:
I/281 : WDS 2001.0 (Mason+ 2001)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 F11.5 d MJD Modified Julian Date (JD-2400000.5)
13- 20 F8.4 mas dRA Separation in Right Ascension (1)
22- 29 F8.4 mas dDE Separation in Declination (1)
31- 35 F5.1 uarcsec MinRe Reweighted minor axis uncertainty (1)
37- 43 F7.1 uarcsec MaxRe Reweighted major axis uncertainty (1)
45- 50 F6.2 deg phi Angle between the major ellipse axis
and the RA axis (2)
52- 58 F7.1 uarcsec RARe Reweighted Right Ascension uncertainty (1)
60- 65 F6.1 uarcsec DERe Reweighted Declination uncertainty (1)
67- 74 F8.5 --- RatRe Reweighted σRA,Dec2/
σRAσDec ratio (1)
76- 80 F5.1 uarcsec MinNF Minor axis uncertainty with noise floor (1)
82- 87 F6.1 uarcsec MaxNF Major axis uncertainty with noise floor (1)
89- 94 F6.1 uarcsec RANF Right Ascension uncertainty with noise
floor (1)
96-101 F6.1 uarcsec DENF Declination uncertainty with noise floor
103-110 F8.5 --- RatNF The σRA,Dec2/σRAσDec
ratio with noise floor (1)
112-115 I4 --- Nscans Number of scans
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Note (1): All quantities are in the ICRS 2000.0 reference frame.
The reweighted uncertainty values presented in this data have all been
scaled by a factor of 6.637 over the formal (internal) uncertainties
within each given night. Alternatively, a noise floor is introduced to
the uncertainties at a value of 142 microarcseconds; both methods of
accounting for excess scatter in the data are used in modeling the
system to determine systematic uncertainties.
Note (2): Measured from increasing differential right ascension through
increasing differential declination (the position angle of the
uncertainty ellipse's orientation is 90-phi). Introducing a noise
floor to the data preserves this orientation angle.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 F9.4 yr ObsDate Year of the observation, in decimal years
11- 15 F5.3 mas rho Separation
17- 21 F5.1 deg theta Position angle (1)
23- 28 F6.3 mas e_rhol ?=-9.999 Published uncertainty in rho
30- 33 F4.1 deg e_thetal ?=-9.9 Published uncertainty in theta
35- 39 F5.3 mas e_rho Reweighted uncertainty in rho
41- 44 F4.1 deg e_theta Reweighted uncertainty in theta
46 I1 --- Nobs Number of individual measurements averaged
in ObsDate
48 I1 --- Group [1/4] Subset assignment (2)
50 I1 --- Out [0/1] Outlier? (3)
52 I1 --- Source [0/1] Indicates whether the original paper
could be found (1) or not (0) (4)
54-169 A116 --- Refs Reference(s)
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Note (1): In most cases theta has been changed by 180 degrees from the value
appearing in the original works.
Note (2): Subset assignment, defined as follows:
1 = visual observations with measurement uncertainties estimated by
the original authors;
2 = interferometric observations with measurement uncertainties
estimated by the original authors;
3 = visual observations without measurement uncertainties estimated
by the original authors;
4 = interferometric observations without measurement uncertainties
estimated by the original authors.
Note (3): Outlier, defined as follows:
0 = measurement is a 3-σ outlier in either rho or theta
and has not been used for fitting.
1 = measurement used in fitting.
Note (4): If the original paper could not be found, secondary references
(i.e. the WDS catalog, Cat. I/281) was used instead.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 11 F11.5 d MJD Modified Julian Date (JD-2400000.5)
13- 20 F8.4 km/s RVA ?=-99.9999 Radial velocity of κ Peg A
22- 28 F7.4 km/s e_RVA ?=-9.9999 The 1σ uncertainty in RVA (1)
30- 37 F8.4 km/s RVBa ?=-99.9999 Radial velocity of κ Peg Ba
39- 45 F7.4 km/s e_RVBa ?=-9.9999 The 1σ uncertainty in RVBa (1)
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Note (1): The uncertainties presented have been scaled from the formal
(internal) uncertainties to reflect the scatter about a best-fit
models. The scaling factor for component A velocities was 1.073;
for Ba, it was 1.184.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 9 F9.3 d MJD Modified Julian Date (JD-2400000.5)
11- 16 F6.2 km/s RVBa Radial velocity for κ Pegasi Ba
18- 22 F5.3 km/s e_RVBa Error in RVBa
24 I1 --- Set [1/2] Set of data (1)
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Note (1): Set is defined as follows:
1 = Lick Observatory data from Henroteau (1918LicOB...9..120H 1918LicOB...9..120H);
Luyten (1934ApJ....79..449L 1934ApJ....79..449L) determined the uncertainties of
this data set from the scatter to a model at 1.66km/s;
these values are consistent with the present solution.
2 = CORAVEL data from Mayor & Mazeh (1987A&A...171..157M 1987A&A...171..157M);
the uncertainties have been reweighted by a factor of 2.31 from
the original work, in order that they might be combined with
other data sets for a simultaneous fit.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 02-Jan-2007