J/A+A/693/A289 Gaia-ESO survey spectroscopic binaries (Van der Swaelmen+, 2025)
The Gaia-ESO survey: New spectroscopic binaries in the Milky Way.
Van der Swaelmen M., Merle T., Van Eck S., Jorissen A., Magrini L.,
Randich S., Vallenari A., Zwitter T., Traven G., Viscasillas Vazquez C.,
Bragaglia A., Casey A., Frasca A., Jimenez-Esteban F., Pancino E.,
Worley C. C., Zaggia S.
<Astron. Astrophys. 693, A289 (2025)>
=2025A&A...693A.289V 2025A&A...693A.289V (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, spectroscopic ; Radial velocities
Keywords: techniques: radial velocities - techniques: spectroscopic -
binaries: close - binaries: spectroscopic
Abstract:
The Gaia-ESO survey (GES) is a large public spectroscopic survey that
acquired spectra for more than 100000 stars across all major
components of the Milky Way. In addition to atmospheric parameters and
stellar abundances that have been derived in previous papers of this
series, the GES spectra allow us to detect spectroscopic binaries with
one (SB1), two (SB2), or more (SBn≥3) components.
The present paper discusses the statistics of GES SBn≥2 after
analysing 160727 GIRAFFE HR10 and HR21 spectra, amounting to 37565
unique Milky Way field targets.
Cross-correlation functions (CCFs) have been re-computed thanks to a
dozen spectral masks probing a range of effective temperatures
(3900K<Teff<8000K), surface gravities (1.0<logg<4.7), and
metallicities (-2.6<[Fe/H]<0.3). By optimising the mask choice for a
given spectrum, the newly computed, so-called Nacre (NArrow
CRoss-correlation Experiment) CCFs are narrower and allow more stellar
components to be unblended than standard masks. The Doe (Detection Of
Extrema) extremum-finding code then selects the individual components
and provides their radial velocities.
From the sample of HR10 and HR21 spectra corresponding to 37 565
objects, the present study leads to the detection of 322 SB2, ten SB3
(three of them being tentative), and two tentative SB4. In particular,
compared to our previous study, the Nacre CCFs allowed us to multiply
the number of SB2 candidates by ≃1.5. The colour-magnitude diagram
reveals, as expected, the shifted location of the SB2 main sequence. A
comparison between the SB identified in Gaia DR3 and the ones detected
in the present work was performed and the complementarity of the two
censuses is discussed. An application to the mass-ratio determination
is presented, and the mass-ratio distribution of the GES SB2 is
discussed. When accounting for the SB2 detection rate, an SB2
frequency of ≃1.4% is derived within the present stellar sample of
mainly FGK-type stars.
As primary outliers identified within the GES data, SBn spectra
produce a wealth of information and useful constraints for the binary
population synthesis studies.
Description:
table A1: Cross match of the SB2 sample and the Gaia DR3
table B1: Velocity time series for the iDR5 SB2 sample
table C1: Mass ratios of SB2
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 83 322 Cross match of the SB2 sample and the Gaia DR3
tableb1.dat 129 863 Velocity time series for the iDR5 SB2 sample
tablec1.dat 34 148 Mass ratios of SB2
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- CNAME Gaia-ESO CNAME
18- 36 I19 --- GaiaDR3 Gaia source ID
38- 45 F8.3 mas plx ? Gaia parallax
47- 53 F7.3 mas e_plx ? Uncertainty on Gaia parallax
55- 60 F6.3 mag Gmag Gaia G magnitude
62- 66 F5.3 mag BP-RP Gaia BP-RP colour
68- 74 F7.3 --- RUWE ? RUWE
76- 83 F8.3 km/s RV ? Gaia radial velocity
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- CNAME Gaia-ESO CNAME
18- 29 F12.6 d MJD Modified Julian date
31- 37 F7.2 km/s RV1 Radial velocity of the primary component
39- 42 F4.2 km/s e_RV1 Uncertainty on the radial velocity of
the primary component
44- 50 F7.2 km/s RV2 Radial velocity of the secondary component
52- 57 F6.2 km/s e_RV2 Uncertainty on the radial velocity of
the secondary component
59 A1 --- Mode [A/M] Component assignation mode (1)
61- 64 A4 --- Setup GIRAFFE setup
66 I1 --- bestMaskId [1/4] Best mask ID (2)
68- 69 I2 --- Ngood Number of good NACRE CCFs
71- 75 F5.3 --- K1 Absolute average height of the
first-component's CCF peak
77- 81 F5.3 --- k1 Normalised average heights of
primary component's peak
83- 87 F5.3 --- s_k1 Standard deviation around k_1
89- 93 F5.3 --- k2 Normalised average heights of
secondary component's peak
95- 99 F5.3 --- s_k2 Standard deviation around k_2
101-105 F5.3 --- H1 Absolute height of first-component's CCF
peak (measured in the best mask)
107-111 F5.3 --- h1 Normalised height of primary component's
peak (measured in the best mask)
113-117 F5.3 --- h2 Normalised height of secondary component's
peak (measured in the best mask)
119-123 F5.2 km/s W1 Width of primary component's peak
(measured in the best mask)
125-129 F5.2 km/s W2 Width of secondary component's peak
(measured in the best mask)
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Note (1): component assignation mode as follows:
A = automatic
M = manual
Note (2): best mask ID as follows:
1 = alpha Cen A
2 = beta Ara
3 = mu Leo
4 = Sun
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Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- CNAME Gaia-ESO CNAME
18- 21 F4.2 --- q Mass ratio
23- 26 F4.2 --- e_q Uncertainty on the mass ratio
28 I1 --- Nepoch Number of epochs
30- 34 A5 --- Flag Flag "component one is primary"
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Acknowledgements:
Mathieu Van der Swaelmen, mvds.amt(at)orange.fr
(End) Patricia Vannier [CDS] 21-Jan-2025