J/MNRAS/517/5569 Stellar properties of Sun-like stars from SDST II (Liu+, 2022)
Survey for distant solar twins (SDST) - II. Design, observations, and data.
Liu F., Murphy M.T., Lehmann C., Flynn C., Smith D., Kos J., Berke D.A.,
Martell S.L.
<Mon. Not. R. Astron. Soc. 517, 5569 (2022)>
=2022MNRAS.517.5569L 2022MNRAS.517.5569L (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Stars, normal ; Stars, G-type ; Positional data ;
Photometry ; Optical ; Parallaxes, trigonometric ; Stars, masses ;
Stars, distances ; Extinction ; Effective temperatures
Keywords: methods: observational - stars: fundamental parameters -
stars: general - stars: solar-type
Abstract:
Studies of solar twins have key impacts on the astronomical community,
but only ∼100-200 nearby solar twins (<1 kpc) have been reliably
identified over the last few decades. The aim of our survey (SDST) is
to identify ∼150-200 distant solar twins and analogues (up to ≲4
kpc) closer to the Galactic Centre. We took advantage of the precise
Gaia and Skymapper surveys to select Sun-like candidates in a 2-deg
field, which were observed with the HERMES spectrograph on the
Anglo-Australian Telescope. We successfully built up the required
signal-to- noise ratio (25-per-pixel in the HERMES red band) for most
targets as faint as Gaia G of 17.4 mag. The stellar
photometric/astrometric parameters (e.g. Teff, log g, mass) of our
candidates are derived in this paper, while the spectroscopic
parameters will be presented in the third paper in this SDST series.
The selection success rate - the fraction of targets which belong to
solar twins or analogues - was estimated from simulated survey data
and the Besancon stellar population model, and compared with the
actual success rate of the survey. We find that expected and actual
success rates agree well, indicating that the numbers of solar twins
and analogues we discover in SDST are consistent with expectations,
affirming the survey approach. These distant solar analogues are prime
targets for testing for any variation in the strength of
electromagnetism in regions of higher dark matter density, and can
make additional contributions to our understanding of, e.g. Galactic
chemical evolution in the inner Milky Way.
Description:
As SDST I demonstrated a new method for measuring the stellar
parameters of Sun-like stars from HERMES spectra, we present the
stellar parameter measurements and a catalogue of the new solar twin
and analogue discoveries in SDST II. These stars are closer to
Galactic center <4kpc from us, confirmed twin candidates will be used
to probe for variations in α (α variations map closer to
galactic center is linked to strong variations of dark matter
density). Due to 17-18 mag faint range it make challenging to obtain
their spectra with sufficient SNR for spectroscopic determinations.
With GaiaEDR3 and Skymapper are efficient to select Sun-like
candidates down to Gaia G < 18-19mag. More, the AAT Hermes
spectrograph make us confirme candidates down to Gaia G<17.4mag with
SNR=>25 in red band based on EPIC method measuring the spectroscopic
stellar parameters (i.e see more in SDST I, Paper I). Thus based on
photometric and astrometric target and field selections (i.e section
2.2 and 2.3), we collect spectra of 877 Sun-like candidates.
As fully exposed in details on section 3, we observe selected target
with HERMES and 2dF on AAT Observatory in four bands covering ranges
as : 4713-4903, 5647-5873, 6478-6737, and 7585-7887Å. Data were
reduced with 2dfdr software, also we proceed to sky subtraction and
telluric correction on all spectra (i.e see section 3.2). Finally, all
spectra are available at https://datacentral.org.au, the SDST III will
show physical parameter directly extracted from these spectrosopic
data (i.e extracted from section 4.2: we do require accurate stellar
metallicity [Fe/H] from spectroscopy to verify their likeness to the
Sun which will be computed with the EPIC algorithm in SDST III, Paper
III).
For now SDST II in table2.dat, we present photometric, astrometric and
(Teff, logg, M*) stellar properties from expressions and analytical
models (i.e section 4.2) of the 877 selected solar-like candidates
(i.e extracted from section 4.1: spectroscopic verification of these
faint candidates provides us with a completely new knowledge of
distant Sun-like stars in several distance bins from 1-4 kpc in the
inner region of Milky Way). More, see selection success rate of solar
analogues in section 4.3 and AAT program A/2021A/005 fits at :
https://archives.datacentral.org.au/results/
21089ec0-21ad-4d82-a927-397b82f91fe1 and SDST III original data
product at zenodo : https://zenodo.org/records/7332606 .
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 81 877 The stellar information and derived properties
of observed solar twins and analogues candidates
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See also:
J/MNRAS/506/150 : The GALAH+ Survey DR3 (Buder+, 2021)
J/MNRAS/499/2196 : Carbon and nitrogen in solar twins (Botelho+, 2020)
J/MNRAS/495/3961 : Planet-hosting stars chemical compositions (Liu+, 2020)
J/MNRAS/474/2580 : Temporal evolution of neutron-capture elements (Spina+,2018)
J/MNRAS/463/696 : M67 solar twins chemical compositions (Liu+, 2016)
J/A+A/649/A3 : Gaia Early Data Release 3 photometric passbands
(Riello+, 2021)
J/A+A/640/A81 : Abundances of 72 solar-type stars (Nissen+, 2020)
J/A+A/639/A127 : Age-chemical-clocks-metallicity relations (Casali+, 2020)
J/A+A/619/A73 : Solar Twins age-chromospheric activity
(Lorenzo-Oliveira+, 2018)
J/A+A/605/A89 : Abundances of microlensed Bulge dwarf stars. VI.
(Bensby+, 2017)
J/A+A/589/A17 : Abundance analysis of solar twin HIP 100963
(Yana Galarza+, 2016)
J/A+A/574/A124 : Spectroscopy of solar twins and analogues (Datson+, 2015)
J/A+A/562/A71 : Chemical abundances of solar neighbourhood dwarfs
(Bensby+, 2014)
J/A+A/558/A53 : Milky Way global survey of star clusters. II.
(Kharchenko+, 2013)
J/A+A/512/A54 : Teff and Fbol from Infrared Flux Method (Casagrande+, 2010)
J/A+A/508/L17 : Abundances in solar analogs (Ramirez+, 2009)
J/ApJ/791/14 : 18 Sco atomic data and equivalent widths (Melendez+, 2014)
J/ApJ/865/68 : Abundances for 79 Sun-like stars within 100pc (Bedell+,2018)
II/379 : SkyMapper Southern Sky Survey. DR4 (Onken+, 2024)
II/358 : SkyMapper Southern Sky Survey. DR1.1 (Wolf+, 2018)
I/352 : Distances to 1.47 billion stars in Gaia EDR3
(Bailer-Jones+, 2021)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- GaiaEDR3 Unique source identifier from GaiaEDR3
(GaiaEDR3ID)
21- 26 F6.3 mag Gmag Mean magnitude (Vega) (Gaia_G)
28- 32 F5.3 mas Plx Absolute stellar parallax of the source at
the Ep=2016.0 taken from Gaia EDR3
(Parallax)
34- 38 F5.3 mas e_Plx Standard error of the stellar parallax at
Ep=2016.0 taken from Gaia EDR3
(σParallax)
40- 43 I4 pc rpgeo Distance taken from Bailer-Jones et al.
2021AJ....161..147B 2021AJ....161..147B, Cat. I/352 (Distance)
45- 49 F5.3 mag (BP-RP)0 Dereddened colour index as exposed in
equation 1 of section 2.3.2 (BP-RPdred)
51- 55 F5.3 mag MG-AG Absolute magnitude in Gaia G less its
corresponding exctintion AG as exposed in
equation 2 of section 2.3.3 (MG0-AG)
57- 60 I4 K Teff Effective temperature derived following the
method presented in Casagrande et al.
2021MNRAS.507.2684C 2021MNRAS.507.2684C and explanations in our
section 4.2 (Teff)
62- 63 I2 K e_Teff Mean standard error of Teff (σTeff)
65- 69 F5.3 [cm/s2] logg Surface gravity derived with equation 4 of
section 4.2 (logg)
71- 75 F5.3 [cm/s2] e_logg Mean standard error of logg (σlogg)
77- 81 F5.3 Msun M* Stellar masses determined using the
Yonsei-Yale isochrones as exposed in
section 4.2 (Mass)
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History:
From electronic version of the journal
References:
Lehmann et al., Paper I 2022MNRAS.512...11L 2022MNRAS.512...11L
Lehmann et al., Paper III 2023MNRAS.521..148L 2023MNRAS.521..148L
(End) Luc Trabelsi [CDS] 27-Oct-2025