J/A+A/623/A116 Galactic Cepheids and RR Lyrae multiplicity. I. (Kervella+, 2019)
Multiplicity of Galactic Cepheids and RR Lyrae stars from Gaia DR2.
I. Binarity from proper motion anomaly.
Kervella P., Gallenne A., Evans N.R., Szabados L., Arenou F., Merand A.,
Proto Y., Karczmarek P., Nardetto N., Gieren W., Pietrzynski G.
<Astron. Astrophys. 623, A116 (2019)>
=2019A&A...623A.116K 2019A&A...623A.116K (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Stars, variable ; Stars, double and multiple ;
Proper motions
Keywords: stars: variables: Cepheids - stars: variables: RR Lyrae - astrometry -
proper motions - binaries: general - binaries: close
Abstract:
Classical Cepheids (CCs) and RR Lyrae stars (RRLs) are important
classes of variable stars used as standard candles to estimate
galactic and extragalactic distances. Their multiplicity is
imperfectly known, particularly for RRLs. Astoundingly, only one RRL
is convincingly demonstrated to be a binary as of today, TU UMa, out
of tens of thousands of known RRLs. We aim at detecting the binary and
multiple stars present in a sample of Milky Way CCs and RRLs. In the
present article, we combine the Hipparcos and Gaia DR2 positions to
determine the mean proper motion of the targets, and we search for
proper motion anomalies (PMa) caused by close-in orbiting companions.
We identify 57 CC binaries from PMa out of 254 tested stars, and 75
additional candidates, confirming the high binary fraction of these
massive stars. For 28 binary CCs, we determine the companion mass by
combining their spectroscopic orbital parameters and astrometric PMa.
We detect 13 RRLs showing a significant PMa out of 198 tested stars,
and 61 additional candidates. We determine that the binarity fraction
of CCs is likely above 80%, while that of RRLs is at least 7%. The
newly detected systems will be useful to improve our understanding of
their evolutionary states. The discovery of a significant number of
RRLs in binary systems also resolves the long-standing mystery of
their extremely low apparent binarity fraction.
Description:
Measured proper motion anomalies of Galactic Cepheids and RR Lyrae
stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ceppma.dat 148 253 Proper motion anomalies of Cepheids
rrlyrpma.dat 149 190 Proper motion anomalies of RR Lyrae stars
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
J/A+A/623/A117 : Galactic Cepheids & RR Lyrae multiplicity II (Kervella+, 2019)
Byte-by-byte Description of file: ceppma.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Cepheid name
12- 16 F5.2 d Period Pulsation period
18- 23 F6.3 mas Plx Parallax
25 A1 --- r_Plx [GHB] Origin of parallax (1)
27- 34 F8.3 mas/yr pmRAHG Hip-Gaia proper motion in
RA direction (pmRA*cosDE)
36- 41 F6.3 mas/yr e_pmRAHG Standard error of Hip-Gaia PM in
right ascension direction
43- 50 F8.3 mas/yr pmDEHG Hip-Gaia proper motion in
declination direction
52- 57 F6.3 mas/yr e_pmDEHG Standard error of Hip-Gaia PM in
declination direction
59- 66 F8.3 mas/yr dpmRAHHG Hip-HG proper motion anomaly in
RA direction (pmRA*cosDE)
68- 73 F6.3 mas/yr e_dpmRAHHG Standard error of differential Hip-HG PM in
right ascension direction
75- 82 F8.3 mas/yr dpmDEHHG Hip-HG proper motion anomaly in
declination direction
84- 89 F6.3 mas/yr e_dpmDEHHG Standard error of differential Hip-HG PM in
declination direction
91- 95 F5.2 mas/yr HHGSNR Hip-HG proper motion anomaly SNR
97-104 F8.3 mas/yr dpmRAGHG GDR2-HG proper motion anomaly in
RA direction (pmRA*cosDE)
106-111 F6.3 mas/yr e_dpmRAGHG Standard error of differential GDR2-HG PM in
right ascension direction
113-120 F8.3 mas/yr dpmDEGHG GDR2-HG proper motion anomaly in
declination direction
122-127 F6.3 mas/yr e_dpmDEGHG Standard error of differential GDR2-HG PM in
declination direction
129-133 F5.2 mas/yr GHGSNR GDR2-HG proper motion anomaly SNR
135 I1 --- binflag Binarity flag
137 I1 --- Qflag Quality flag on Arenou et al.
(2018A&A...616A..17A 2018A&A...616A..17A) criteria
139-143 F5.2 --- RUWE Gaia DR2 renormalized unit weight error
145 I1 --- Rflag Quality flag on RUWE<1.4 criterion
147-148 A2 --- bintype Binary type from Szabados database (2)
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Note (1): Parallax reference as follows:
G = Gaia DR2, Cat. I/345
H = Hipparcos 2 catalog, Cat,. I/311
B = derived from the photometric parallax of Berdnikov et al.
(2000, Cat. J/A+AS/143/211)
Note (2): The binary type is indicated using the following code:
B = spectroscopic binary
B: = spectroscopic binary (confirmation is needed)
b = photometric companion, physical relation should be investigated
O = spectroscopic binary with known orbit
V = visual binary
BV = spectroscopic binary; visual binary
OV = spectroscopic binary with known orbit; visual binary
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Byte-by-byte Description of file: rrlyrpma.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name RR Lyrae star name
12- 16 F5.2 d Period Pulsation period
18- 23 F6.3 mas Plx Parallax
25 A1 --- r_Plx [G] Origin of parallax
(G=Gaia DR2, Cat. I/345)
27- 34 F8.3 mas/yr pmRAHG Hip-Gaia proper motion in RA direction
(pmRA*cosDE)
36- 41 F6.3 mas/yr e_pmRAHG Standard error of Hip-Gaia PM in
right ascension direction
43- 50 F8.3 mas/yr pmDEHG Hip-Gaia proper motion in
declination direction
52- 57 F6.3 mas/yr e_pmDEHG Standard error of Hip-Gaia PM in
declination direction
59- 66 F8.3 mas/yr dpmRAHHG Hip-HG proper motion anomaly in
RA direction (pmRA*cosDE)
68- 73 F6.3 mas/yr e_dpmRAHHG Standard error of differential Hip-HG PM in
right ascension direction
75- 82 F8.3 mas/yr dpmDEHHG Hip-HG proper motion anomaly in
declination direction
84- 89 F6.3 mas/yr e_dpmDEHHG Standard error of differential Hip-HG PM in
declination direction
91- 95 F5.2 mas/yr HHGSNR Hip-HG proper motion anomaly SNR
97-104 F8.3 mas/yr dpmRAGHG GDR2-HG proper motion anomaly in
RA direction (pmRA*cosDE)
106-111 F6.3 mas/yr e_dpmRAGHG Standard error of differential GDR2-HG PM in
right ascension direction
113-120 F8.3 mas/yr dpmDEGHG GDR2-HG proper motion anomaly in
declination direction
122-127 F6.3 mas/yr e_dpmDEGHG Standard error of differential GDR2-HG PM in
declination direction
129-133 F5.2 mas/yr GHGSNR GDR2-HG proper motion anomaly SNR
135 I1 --- binflag Binarity flag
137 I1 --- Qflag Quality flag on Arenou et al.
(2018A&A...616A..17A 2018A&A...616A..17A) criteria
139-143 F5.2 --- RUWE Gaia DR2 renormalized unit weight error
145 I1 --- Rflag Quality flag on RUWE<1.4 criterion
147-149 A3 --- RRtype RR lyrae variable subtype
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Acknowledgements:
Pierre Kervella, pierre.kervella(at)obspm.fr
References:
Kervella et al., Paper II 2019A&A...623A.117K 2019A&A...623A.117K, Cat. J/A+a/623/A117
(End) Patricia Vannier [CDS] 28-Jan-2019