J/AJ/126/3017 Distances of Cataclysmic variables (Thorstensen, 2003)
Parallaxes and distance estimates for 14 cataclysmic variable stars.
Thorstensen J.R.
<Astron. J., 126, 3017-3029 (2003)>
=2003AJ....126.3017T 2003AJ....126.3017T
ADC_Keywords: Stars, variable ; Parallaxes, trigonometric ; Stars, distances
Keywords: binaries: general - novae, cataclysmic variables - stars: distances -
stars: variables: other
Abstract:
The 2.4m Hiltner Telescope at MDM Observatory was used in an attempt
to measure trigonometric parallaxes for 14 cataclysmic variable stars.
Techniques are described in detail. In the best cases the parallax
uncertainties are below 1mas, and significant parallaxes are found
for most of the program stars. A Bayesian method that combines the
parallaxes together with proper motions and absolute magnitude
constraints is developed and used to derive distance estimates and
confidence intervals. The most precise distance derived here is for WZ
Sge, for which is found to be 43.3+1.6-1.5pc. Six Luyten
Half-Second stars with previous precise parallax measurements were
remeasured to test the techniques, and good agreement was found.
Description:
All the observations are from the f/7.5 focus of the 2.4m Hiltner
Telescope at MDM Observatory on Kitt Peak, Arizona.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 93 1203 Positions, Magnitudes, Parallaxes, and Proper Motions
table4.dat 134 14 Parallaxes, proper motions, and distances
table5.dat 50 9 Measured and theoretical absolute magnitudes
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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- 17 A17 --- Field Cataclysmic Variable Star name,
as field designation (1)
19 A1 --- f_Field [*] Indicates the program star
21- 22 I2 h RAh Hour of Right Ascension (J2000) (2)
24- 25 I2 min RAm Minute of Right Ascension (J2000) (2)
27- 31 F5.2 s RAs Second of Right Ascension (J2000) (2)
33 A1 --- DE- Sign of the Declination (J2000) (2)
34- 35 I2 deg DEd Degree of Declination (J2000) (2)
37- 38 I2 arcmin DEm Arcminute of Declination (J2000) (2)
40- 43 F4.1 arcsec DEs Arcsecond of Declination (J2000) (2)
45 I1 --- Weight [0/1] Reference star indicator (3)
47- 49 I3 mas sigma Scatter around the best astrometric fit (4)
51- 55 F5.2 mag Vmag The V band magnitude (5)
57- 61 F5.2 mag V-I The (V-I) color (5)
63- 68 F6.1 mas plx Fitted parallax
70- 73 F4.1 mas e_plx Error in plx
75- 80 F6.1 mas/yr pmX X (RA) tangent-plane direction proper motion
82- 87 F6.1 mas/yr pmY Y (DE) tangent-plane direction proper motion
89- 92 F4.1 mas/yr sigpm Uncertainty in proper motion (per coordinate)
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Note (1): The fourth star listed in the LHS 1889 field proved to be
a hitherto unknown L3.5 dwarf.
Note (2): The celestial coordinates are from mean CCD images and
are referred to the USNO A2.0 (Cat. I/252), which is in turn aligned
with the ICRS; the epochs of the images used are typically around
1998. Coordinates should be accurate to ∼0.3" external and somewhat
better than this internally.
Note (3): Reference star indicator:
0 = not used as a reference star;
1 = used as a reference star.
Note (4): In a few cases these are very large (e.g. close pairs which
were intermittently resolved).
Note (5): Typical external uncertainties of 0.05mag and internal
consistency somewhat better than that.
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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- 8 A8 --- Star Star name
11- 14 F4.1 mas plx Relative parallax
16- 18 F3.1 mas e_plx rms uncertainty on plx derived from the
goodness of fit
20- 22 F3.1 mas e_plx2 rm uncertainty on plx derived from the
scatter of the reference stars
24- 27 F4.1 mag PLX Absolute parallax
29- 31 F3.1 mag e_PLX rms uncertainty on PLX
33- 37 F5.1 pc dLK ? Most probable value of the distance
based on absolute parallax
and a Lutz-Kelker correction
39- 44 F6.1 pc d(pi+mu) Bayesian distance estimate considering
the parallax and proper motion prior only
46- 51 F6.1 pc E_d(pi+mu) Error on d(pi+mu) (upper limit)
53- 57 F5.1 pc e_d(pi+mu) Error on d(pi+mu) (lower limit)
59- 64 F6.1 mas/yr pmRA Proper motion in right ascension
66- 70 F5.1 mas/yr pmDE Proper motion in declination
72- 74 F3.1 mas/yr e_pmRA rms uncertainty on pmRA and pm DE
76- 80 F5.2 mag mag ? Apparent magnitude
82- 85 F4.1 mag MAG ? Assumed absolute magnitude
87- 89 F3.1 mag e_MAG ? 1sigma combined uncertainty for
mag and MAG
91- 93 F3.1 mag m-M ? Distance modulus
95- 97 F3.1 mag e_m-M ? rms uncertainty on m-M
99-103 F5.1 1/mas 1/piabs Inverse of absolute parallax
105-109 F5.1 1/mas E_1/piabs Error on 1/piabs (upper limit)
111-115 F5.1 1/mas e_1/piabs Error on 1/piabs (lower limit)
118-122 F5.1 pc d(pi+mu+m-M) Distance, taking account parallax, proper
motion and distance modulus as prior
124-128 F5.1 pc E_d(pi+mu+m-M) Error on distance (upper limit)
130-134 F5.1 pc e_d(pi+mu+m-M) Error on distance (lower limit)
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Star Star name
11- 14 F4.2 h Porb Orbital period
16- 17 I2 deg Incl Inclination
19- 20 I2 deg e_Incl rms uncertainty on Incl
22- 25 F4.1 mag Vmax Maximum V magnitude
27- 29 F3.1 mag VMAG Predicted maximum absolute V magnitude
31- 33 F3.1 mag E_VMAG Error on VMAG (upper limit)
35- 37 F3.1 mag e_VMAG Error on VMAG (lower limit)
39- 41 F3.1 mag VMAGm Measured maximum absolute V magnitude
43- 45 F3.1 mag E_VMAGm Error on VMAGm (upper limit)
47- 49 F3.1 mag e_VMAGm Error on VMAGm (lower limit)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 12-Jan-2004