Progress on the calibration of surface brightness-color relations for early- and late-type stars

Salsi, A.; Nardetto, N.; Mourard, D.; Graczyk, D.; Taormina, M.; Creevey, O.; Hocdé, V.; Morand, F.; Perraut, K.; Pietrzyński, G.; Schaefer, Gail H.

doi:10.1051/0004-6361/202140763

Cited by 17 publications

(17 citation statements)

References 40 publications

(54 reference statements)

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“…V − K s > 1 mag) at the 10% level, while SBCRs for early-type stars (i.e. V − K s < 1 mag) have recently been improved from around 7% precision Challouf et al (2014) to 2-3% (Salsi et al 2021). Years ago, Fouque & Gieren (1997) observed a significant difference in the SBCRs according to the luminosity class of stars.…”

Section: Introductionmentioning

confidence: 99%

Theoretical analysis of surface brightness-colour relations for late-type stars using MARCS model atmospheres

Salsi

Nardetto

Plez³

et al. 2022

A&A

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Context. Surface brightness-colour relations (SBCRs) are largely used for general studies in stellar astrophysics and for determining extragalactic distances. Based on a careful selection of stars and a homogeneous methodology, it has been recently shown that the SBCR for late-type stars depends on the spectral type and luminosity class. Aims. Based on simulated spectra of late-type stars using MARCS model atmospheres, our aim is to analyse the effect of stellar fundamental parameters on the surface brightness. We also compare theoretical and recent empirical SBCRs. Methods. We used MARCS model atmospheres to compute spectra and obtain the surface brightness of stars. We first explored the parameter space of MARCS (i.e. effective temperature, log g, [Fe/H], microturbulence, and mass) in order to quantify their impact on the surface brightness. Then we considered a relation between the effective temperature and log g for late dwarfs and giants, as well as a solar metallicity, in order to allow a consistent comparison of theoretical and empirical SBCRs. Results. We find that the SBCR is not sensitive to the microturbulence and mass. The effect of metallicity on the SBCR is found to be larger for dwarfs than for giants. It is also larger when considering larger V - Ks values. We also find that a difference of 0.5 dex in metallicity between Galactic and LMC SBCRs does not affect the recent LMC distance determination, based on eclipsing binaries, by more than 0.4%. By comparing theoretical with empirical SBCRs, we find a good agreement of less than 2σ for F5-K7 dwarfs and giants stars, while a larger discrepancy is found for M dwarfs and giants (about 4-6σ). The surface gravity properties, as modelled in MARCS, explain the differences in the empirical SBCRs in terms of class. We finally find that theoretical and empirical SBCRs for Cepheids are consistent. Conclusions. Carefully considering metallicity and log g is mandatory when calibrating or using SBCRs.

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Section: Introductionmentioning

confidence: 99%

Theoretical analysis of surface brightness-colour relations for late-type stars using MARCS model atmospheres

Salsi

Nardetto

Plez³

et al. 2022

A&A

Self Cite

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“…Angular diameter measurements are used to determine empirical surface brightness relations for predicting radii based on photometric colors. [26][27][28] Combined with a precise Gaia parallax 29 and a measurement of the bolometric flux, the angular diameter can be used to derive the physical radius and effective temperature of a star. At the low-mass end of the main sequence, predictions from evolutionary models tend to overestimate the temperatures of stars by 3% and underestimate the radii of stars by 5%.…”

Section: Angular Diameter Of Starsmentioning

confidence: 99%

Design of the new CHARA instrument SILMARIL: pushing for the sensitivity of a 3-beam combiner in the H- and K-band.

Lanthermann

Brummelaar²,

Tuthill³

et al. 2022

Optical and Infrared Interferometry and Imaging VIII

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Optical interferometry is a powerful technique to achieve high angular resolution. However, its main issue is its lack of sensitivity, compared to other observation techniques. Efforts have been made in the previous decade to improve the sensitivity of optical interferometry, with instruments such as PIONIER and GRAVITY at VLTI, or MIRC-X and MYSTIC at CHARA. While those instruments pushed on sensitivity, their design focus was not the sensitivity but relative astrometric accuracy, imaging capability, or spectral resolution. Our goal is to build an instrument specifically designed to optimize for sensitivity. This meant focusing our design efforts on different parts of the instrument and investigating new technologies and techniques. First, we make use of the low noise C-RED One camera using e-APD technology and provided by First Light Imaging, already used in the improvement of sensitivity in recent new instruments. We forego the use of single-mode fibers but still favor an image plane design that offers more sensitivity than a pupil plane layout. We also use a minimum number of optical elements to maximize the throughput of the design, using a long focal length cylindrical mirror. We chose to limit our design to 3 beams, to have the capability to obtain closure phases, but not dilute the incoming flux in more beam combinations. We also use in our design an edge filter to have the capability to observe Hand K-band at the same time. We use a low spectral resolution, allowing for group delay fringe tracking but maximizing the SNR of the fringes for each spectral channel. All these elements will lead to a typical limiting magnitude between 10 and 11 in both H-and K-bands.

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“…The assumptions surrounding the surface brightness estimate of each star represent the most significant potential systematics of the DEB technique. However, previous work has demonstrated consistent models for surface brightness with negligible dependence on metallicity effects [177,178]. Additionally, the systems are difficult to detect due to their detached nature, causing transits to be very short, which limits the number of available distance measurements [14].…”

Section: Anchor Measurementsmentioning

confidence: 99%

Hubble distancing: Focusing on distance measurements in cosmology

Greene,

Cyr-Racine

2021

Preprint

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The Hubble-Lemaître tension is currently one of the most important questions in cosmology. Most of the focus so far has been on reconciling the Hubble constant value inferred from detailed cosmic microwave background measurement with that from the local distance ladder. This emphasis on one number -namely H 0 -misses the fact that the tension fundamentally arises from disagreements of distance measurements. To be successful, a proposed cosmological model must accurately fit these distances rather than simply infer a given value of H 0 . Using the newly developed likelihood package 'distanceladder ', which integrates the local distance ladder into MontePython, we show that focusing on H 0 at the expense of distances can lead to the spurious detection of new physics in models which change late-time cosmology. As such, we encourage the observational cosmology community to make their actual distance measurements broadly available to model builders instead of simply quoting their derived Hubble constant values.

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Progress on the calibration of surface brightness-color relations for early- and late-type stars

Cited by 17 publications

References 40 publications

Theoretical analysis of surface brightness-colour relations for late-type stars using MARCS model atmospheres

Theoretical analysis of surface brightness-colour relations for late-type stars using MARCS model atmospheres

Design of the new CHARA instrument SILMARIL: pushing for the sensitivity of a 3-beam combiner in the H- and K-band.

Hubble distancing: Focusing on distance measurements in cosmology

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