Survey for Distant Solar Twins (SDST) -- II. Design, observations and data

Abstract

Studies of solar twins have key impacts on the astronomical community, but only $\sim$100--200 nearby solar twins ($<$ 1 kpc) have been reliably identified over the last few decades. The aim of our survey (SDST) is to identify $\sim$150--200 distant solar twins and analogues (up to $\lesssim$ 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-degree 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, \logg, 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 Besançon 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.

15 pages, 13 figures. Accepted by MNRAS

References in corpus (29)

• The Gaia mission
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• The GALAH Survey: Scientific Motivation
• Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments
• Molecfit: A general tool for telluric absorption correction II. Quantitative evaluation on ESO-VLT X-Shooter spectra
• High-precision abundances of elements in solar twin stars: Trends with stellar age and elemental condensation temperature
• SkyMapper Southern Survey: Second Data Release (DR2)
• The Solar Twin Planet Search. I. Fundamental parameters of the stellar sample
• Tenth-Order Electron Anomalous Magnetic Moment --- Contribution of Diagrams without Closed Lepton Loops
• High-precision abundances of elements in solar-type stars. Evidence of two distinct sequences in abundance-age relations
• 18 Sco: a solar twin rich in refractory and neutron-capture elements. Implications for chemical tagging
• The temporal evolution of neutron-capture elements in the Galactic discs
• Solar twins in M67
• HIP 56948: A Solar Twin With a Low Lithium Abundance
• The Gaia-ESO survey: the non-universality of the age-chemical-clocks-metallicity relations in the Galactic disc
• The chemical compositions of solar twins in the open cluster M67
• The GALAH survey: The data reduction pipeline
• HD 98618: A Star Closely Resembling our Sun
• The Li-age correlation: the Sun is unusually Li deficient for its age
• Search for a Variation of the Fine Structure around the Supermassive Black Hole in Our Galactic Center
• Subaru Telescope limits on cosmological variations in the fine-structure constant
• Fundamental physics with ESPRESSO: Precise limit on variations in the fine-structure constant towards the bright quasar HE 0515$-$4414
• Detailed chemical compositions of planet hosting stars: I. Exploration of possible planet signatures
• HIP 114328: a new refractory-poor and Li-poor solar twin
• New solar twins and the metallicity and temperature scales of the Geneva Copenhagen Survey
• Spectroscopic study of solar twins and analogues
• Carbon, isotopic ratio ${}^{12}$C/${}^{13}$C and nitrogen in solar twins: constraints for the chemical evolution of the local disc
• Searching for new solar twins: The Inti survey for the Northern Sky
• Survey for Distant Solar Twins (SDST) -- I. EPIC method for stellar parameter measurement

Cited by in corpus (2)

• Survey for Distant Solar Twins (SDST) -- III. Identification of new solar twin and solar analogue stars
• A revised comparison of distant and nearby solar twins