MINESweeper: Spectrophotometric Modeling of Stars in the Gaia Era

Abstract

We present MINESweeper, a tool to measure stellar parameters by jointly fitting observed spectra and broadband photometry to model isochrones and spectral libraries. This approach enables the measurement of spectrophotometric distances, in addition to stellar parameters such as T eff , g log , [Fe/H], [α/Fe], and radial velocity. MINESweeper employs a Bayesian framework and can easily incorporate a variety of priors, including Gaia parallaxes. Mock data are fit in order to demonstrate how the precision of derived parameters depends on evolutionary phase and signal-tonoise ratio. We then fit a selection of data in order to validate the model outputs. Fits to a variety of benchmark stars including Procyon, Arcturus, and the Sun result in derived stellar parameters that are in good agreement with the literature. We then fit combined spectra and photometry of stars in the open and globular clusters M92, M13, M3, M107, M71, and M67. Derived distances, [Fe/H], [α/Fe], and g log −T eff relations are in overall good agreement with literature values, although there are trends between metallicity and g log within clusters that point to systematic uncertainties at the ≈0.1 dex level. Finally, we fit a large sample of stars from the H3 Spectroscopic Survey in which high-quality Gaia parallaxes are also available. These stars are fit without the Gaia parallaxes so that the geometric parallaxes can serve as an independent test of the spectrophotometric distances. Comparison between the two reveals good agreement within their formal uncertainties after accounting for the Gaia zero-point uncertainties.

TOPoS

“…The spectra cover the range 513 -530 nm at a resolving power R∼ 23 000. Using the MINESweeper code (Cargile et al 2020), an analysis of the spectra combined with photometry provides radial velocities, spectrophotometric distances, and abundances ([Fe/H] and [α/Fe]).…”

Two Planets Straddling the Habitable Zone of the Nearby K Dwarf Gl 414A

“…We also determine stellar parameters using MINESweeper, a tool to model stellar photometry using isochrone priors. Full details and validation of this technique can be found in Cargile et al (2020), but briefly, the program can fit broadband photometric stellar spectral energy distributions (SEDs) with models drawn from the MIST (Choi et al 2016) stellar isochrones. The SED models (and corresponding predicted photometry) are computed from grids of ATLAS12 model atmospheres (Kurucz 1970) and the spectrum synthesis code SYNTHE (Kurucz 1993).…”

“…Software: SpecMatch-Emp (Yee et al 2017), isoclassify (Berger et al 2020;Huber et al 2017), MIST (Dotter 2016;Choi et al 2016), MINESweeper (Cargile et al 2020), ATLAS12 (Kurucz 1970), SYNTHE (Kurucz 1993), dynesty (Speagle 2019), RadVel (v1.2.13;, emcee (Foreman-Mackey et al 2013), Forecaster (Chen & Kipping 2017), REBOUND (Rein & Liu 2012;Rein & Tamayo 2015), Astropy (Astropy…”

STEPARSYN: A Bayesian code to infer stellar atmospheric parameters using spectral synthesis

“…In fact, open-source implementations of both methods are available to the astronomical community. Regarding the spectral synthesis method, we find the APOGEE Stellar Parameter and Chemical Abundance Pipeline (ASCAP, García Pérez et al 2016), FERRE (Allende Prieto et al 2006), MINESweeper (Cargile et al 2020), MyGIsFOS (Sbordone et al 2014), The Payne (Ting et al 2019), and Spectroscopy Made Easy (SME, Piskunov & Valenti 2017;Valenti & Piskunov 1996), whereas the EW method is implemented in tools such as ARES+MOOG (Sousa et al 2008;Santos et al 2013), FAMA (Magrini et al 2013), GALA (Mucciarelli et al 2013), SPECIES (Soto & Jenkins 2018), and StePar (Tabernero et al 2019). Interestingly enough, other tools such as iSpec (Blanco-Cuaresma et al 2014), FASMA (Andreasen et al 2017;Tsantaki et al 2020), and BACCHUS (Masseron et al 2016) are designed to derive the stellar atmospheric parameters using both approaches.…”