J/A+A/623/A117 Galactic Cepheids and RR Lyrae multiplicity. II (Kervella+, 2019)
Multiplicity of Galactic Cepheids and RR Lyrae stars from Gaia DR2 -
II. Resolved common proper motion pairs.
Kervella P., Gallenne A., Evans N.R., Szabados L., Arenou F., Merand A.,
Nardetto N., Gieren W., Pietrzynski G.
<Astron. Astrophys. 623, A117 (2019)>
=2019A&A...623A.117K 2019A&A...623A.117K (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, photometry ; Photometry, CCD
Keywords: stars: variables: Cepheids - stars: variables: RR Lyrae - astrometry -
proper motions - binaries: general - binaries: visual
Abstract:
The multiplicity of Classical Cepheids (CCs) and RR Lyrae stars (RRLs)
is still imperfectly known, particularly for RRLs.
In order to complement the close-in short orbital period systems
presented in Paper I (Kervella et al., 2019, Cat. J/A+A/623/A16), we
aim at detecting the wide, spatially resolved companions of the
targets of our reference samples of Galactic CCs and RRLs. Angularly
resolved common proper motion pairs are detected using a simple
progressive selection algorithm to separate the most probable
candidate companions from the unrelated field stars.
We detect 27 resolved, high probability gravitationally bound systems
with CCs out of 456 examined stars, and one unbound star embedded in
the circumstellar dusty nebula of the long-period Cepheid RS Pup.
We find 7 spatially resolved, probable bound systems with RRL
primaries out of 789 investigated stars, and 22 additional candidate
pairs.
We report in particular new companions of three bright RRLs: OV And
(companion of F4V spectral type), RR Leo (M0V) and SS Oct (K2V). In
addition, we discovered resolved companions of 14 stars of various
variability classes that were misclassified as RRLs.
The detection of resolved common proper motion companions around CCs
and RRLs facilitates the validation of their GDR2 parallaxes. The
possibility to conduct a detailed analysis of the resolved coeval
companions of CCs and old population RRLs will also be valuable to
progress on our understanding of their evolutionary path.
Description:
Properties of the classical Cepheids and RR Lyrae stars of the sample
with identified 'Near' or 'Bound' candidate companions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
cepheids.dat 297 135 Cepheids with Near or Bound companions
(table A1 and A2)
rrlyrae.dat 297 105 RR Lyrae stars with Near or Bound companions
(table B1 and B2)
figures/* . 200 Finding charts in pdf
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See also:
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/623/A116 : Galactic Cepheids & RR Lyrae multiplicity. I (Kervella+, 2019)
Byte-by-byte Description of file: cepheids.dat rrlyrae.dat
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Bytes Format Units Label Explanations
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1- 28 A28 --- Name Cepheid name or companion Gaia DR2 name
29 A1 --- n_Name [*] Note on Name (1)
31 A1 --- catg [TNBU] Category (2)
33- 47 F15.11 deg RAdeg Barycentric right ascension (ICRS)
at epoch 2015.5 from Gaia DR2
49- 55 F7.4 mas e_RAdeg Standard error of right ascension
(e_RA*cosDE)
57- 71 F15.11 deg DEdeg Barycentric declination (ICRS)
at epoch 2015.5 from Gaia DR2
73- 79 F7.4 mas e_DEdeg Standard error of declination
81- 90 A10 --- Primary Common name of primary star
92- 98 F7.3 mas PlxAsm Assumed parallax value
100-106 F7.3 mas Plx ? Gaia DR2 parallax
(corrected for zero point)
108-114 F7.3 mas e_Plx ? Standard error on Gaia DR2 parallax
116-120 F5.1 arcsec Sep ? Projected separation from primary
122-127 F6.2 kau Linsep ? Projected linear separation from primary
129-135 F7.3 mas/yr pmRA ? Proper motion in right ascension direction
(pmRA*cosDE)
138-143 F6.3 mas/yr e_pmRA ? Standard error of proper motion in
right ascension direction
145-151 F7.3 mas/yr pmDE ? Proper motion in declination direction
153-159 F7.3 mas/yr e_pmDE ? Standard error of proper motion in
declination direction
161-162 A2 --- r_pmRA Source of proper motion (3)
164-168 F5.2 km/s dvtan ? Differential tangential velocity with
respect to primary star
170-174 F5.2 km/s e_dvtan ? Standard error on differential tangential
velocity with respect to primary star
176-180 F5.2 km/s vesc ? Escape velocity from primary at projected
separation
182-186 F5.2 mag BPmag ? Integrated Gaia DR2 BP mean magnitude
188-192 F5.2 mag Gmag ? Integrated Gaia DR2 G mean magnitude
194-198 F5.2 mag RPmag ? Integrated Gaia DR2 RP mean magnitude
200-204 F5.2 mag Jmag ? 2MASS J band magnitude
206-210 F5.2 mag Hmag ? 2MASS H band magnitude
212-216 F5.2 mag Kmag ? 2MASS K band magnitude
218-222 F5.2 mag W1mag ? WISE W1 band magnitude
224-228 F5.2 mag W2mag ? WISE W2 band magnitude
230-234 F5.2 mag W3mag ? WISE W3 band magnitude
236-240 F5.2 mag W4mag ? WISE W4 band magnitude
242-246 F5.3 mag E(B-V) ? E(B-V) color excess
248-253 F6.2 mag GMAG ? Absolute G band magnitude
255-260 F6.3 [K] logTeff ? Log10 of effective temperature (K)
262-264 A3 --- RRtype RR lyrae variable subtype, for rrlyrae.dat
266-278 A13 --- FileName1 Finding chart, in pdf,
in subdirectory figures
280-297 A18 --- FileName2 Zoomed finding chart, in pdf,
in subdirectory figures
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Note (1): The position and assumed parallax of Polaris are taken from the
Hipparcos 2 catalogue (van Leeuwen, 2007, Cat. I/311).
The expected parallax of delta Cep is the mean value between HST-FGS
(Benedict et al., 2002AJ....123..473B 2002AJ....123..473B) and the Hipparcos 2 catalog
(van Leeuwen, 2007, Cat. I/311).
Note (2): Category as follows:
T = Target
N = Near
B = Bound
U = Unbound
Note (3): Source of proper motion as follows:
HG = Hip2 - Gaia DR2
G2 = Gaia DR2, Gaia collaboration, 2018, Cat. I/345
H2 = Hipparcos 2, van Leeuwen, 2007, Cat. I/311
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Acknowledgements:
Pierre Kervella, pierre.kervella(ar)obspm.fr
References:
Kervella et al., Paper I 2019A&A...623A.116K 2019A&A...623A.116K, Cat. J/A+a/623/A116
(End) Patricia Vannier [CDS] 17-Oct-2018