Angular Sizes, Radii, and Effective Temperatures of B-type Stars from Optical Interferometry with the CHARA Array

Gordon, Kathryn D.; Gies, Douglas R.; Schaefer, Gail H.; Huber, Daniel; Ireland, Michael

doi:10.3847/1538-4357/ab04b2

Cited by 15 publications

(6 citation statements)

References 65 publications

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“…Hence we fix all three diameters to U D = 0.5 mas, which is near the resolution limit in H-band. Gordon et al (2019) measured a uniform diameter of 0.407 ± 0.022 mas for the A component of α Del, consistent with our fixed values. ν Gem also showed no improvement in the fits by letting the UDs vary for the night of 2017Sep30 (calibrator HD219080).…”

Section: Fitting Binary Star Differential Astrometrysupporting

confidence: 90%

ARMADA. I. Triple Companions Detected in B-type Binaries α Del and ν Gem

Gardner

Monnier

Fekel

et al. 2020

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Ground-based optical long-baseline interferometry has the power to measure the orbits of close binary systems at ∼10 μas precision. This precision makes it possible to detect “wobbles” in the binary motion due to the gravitational pull from additional short-period companions. We started the ARrangement for Micro-Arcsecond Differential Astrometry (ARMADA) survey with the Michigan Infra-Red Combiner (MIRC)/MIRC-X instrument at the Center for High Angular Resoloution Astronomy (CHARA) array for the purpose of detecting giant planets and stellar companions orbiting individual stars in binary systems. We describe our observations for the survey, and introduce the wavelength calibration scheme that delivers precision at the tens of microarcseconds level for <02 binaries. We test our instrument performance on a known triple system, κ Peg, and show that our survey is delivering a factor of 10 better precision than previous similar surveys. We present astrometric detections of tertiary components to two B-type binaries: a 30 day companion to α Del, and a 50 day companion to ν Gem. We also collected radial velocity data for α Del with the Tennessee State University Automated Spectroscopic Telescope at Fairborn Observatory. We are able to measure the orbits and masses of all three components in these systems. We find that the previously published radial velocity orbit for the inner pair of ν Gem is not consistent with our visual orbit. The precision achieved for these orbits suggests that our ARMADA survey will be successful at discovering new compact triple systems to A/B-type binary systems, leading to better statistics of hierarchical system architectures and formation history.

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Section: Fitting Binary Star Differential Astrometrysupporting

confidence: 90%

ARMADA. I. Triple Companions Detected in B-type Binaries α Del and ν Gem

Gardner

Monnier

Fekel

et al. 2020

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“…For HD 97633, Maestro et al (2013) measured an angular diameter of 0.740 ± 0.024 mas using PAVO, which is consistent with our result. The PAVO measurements of both Maestro et al (2013) and Gordon et al (2019) led to a smaller value for the angular diameter for HD 3360 (0.311 ± 0.010 mas and 0.280 ± 0.018 mas, respectively). The diameter measurements in both papers are based on only two observations, so they could be more susceptible to systematic errors.…”

Section: Comparison With the Literaturementioning

confidence: 90%

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

Salsi

Nardetto

Mourard

et al. 2021

A&A

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Context. Surface brightness-color relations (SBCRs) are widely used for estimating angular diameters and deriving stellar properties. They are critical to derive extragalactic distances of early-type and late-type eclipsing binaries or, potentially, for extracting planetary parameters of late-type stars hosting planets. Various SBCRs have been implemented so far, but strong discrepancies in terms of precision and accuracy still exist in the literature. Aims. We aim to develop a precise SBCR for early-type B and A stars using selection criteria, based on stellar characteristics, and combined with homogeneous interferometric angular diameter measurements. We also improve SBCRs for late-type stars, in particular in the Gaia photometric band. Methods. We observed 18 early-type stars with the VEGA interferometric instrument, installed on the CHARA array. We then applied additional criteria on the photometric measurements, together with stellar characteristics diagnostics in order to build the SBCRs. Results. We calibrated a SBCR for subgiant and dwarf early-type stars. The RMS of the relation is σFV0 = 0.0051 mag, leading to an average precision of 2.3% on the estimation of angular diameters, with 3.1% for V −K < −0.2 mag and 1.8% for V −K > −0.2 mag. We found that the conversion between Johnson-K and 2MASS-Ks photometries is a key issue for early-type stars. Following this result, we have revisited our previous SBCRs for late-type stars by calibrating them with either converted Johnson-K or 2MASS-Ks photometries. We also improve the calibration of these SBCRs based on the Gaia photometry. The expected precision on the angular diameter using our SBCRs for late-type stars ranges from 1.0 to 2.7%. Conclusions. By reaching a precision of 2.3% on the estimation of angular diameters for early-type stars, significant progress has been made to determine extragalactic distances, such as M31 and M33 galaxies, using early-type eclipsing binaries.

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“…2006). The primary component of this pair (Aa) is identified as the prototype variable star of a class of rapid pulsators (Gordon et al 2019), while the secondary (Ab) is a classical Be star (Wheelwright et al 2009). The SB9 lists system 1310 as a SB1, including the orbital solution of Fitch (1969, P = 10.893 d, e = 0.52), but notes difficulty separating orbital velocities from the variable star pulsations, and that the evidence in this case for a binary nature is "not completely convincing."…”

Section: Results For Individual Systemsmentioning

confidence: 99%

Surveying the Bright Stars by Optical Interferometry. II. A Volume-limited Multiplicity Survey of Main-sequence F Stars

Hutter

Tycner

Zavala

et al. 2019

ApJS

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We present the results of a multiplicity survey for a magnitude-limited sample of 31 classical Be stars conducted with the Navy Precision Optical Interferometer and the Mark III Stellar Interferometer. The interferometric observations were used to detect companions in ten previously known binary systems. For two of these sources (66 Oph and β Cep) new orbital solutions were obtained, while for a third source (υ Sgr) our observations provide the first direct, visual detection of the hot sdO companion to the Be primary star. Combining our interferometric observations with an extensive literature search, we conclude that an additional four sources (o Cas, 15 Mon, β Lyr, and β Cep) also contain wider binary components that are physical companions to the narrow binaries, thus forming hierarchical multiple systems. Among the sources not previously confirmed as spectroscopic or visual binaries, BK Cam was resolved on a number of nights within a close physical proximity of another star with relative motion possibly suggesting a physical binary. Combining our interferometric observations with an extensive literature search, we provide a detailed listing of companions known around each star in the sample, and discuss the multiplicity frequency in the sample. We also discuss the prospects for future multiplicity studies of classical Be stars by long baseline optical interferometry.

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Angular Sizes, Radii, and Effective Temperatures of B-type Stars from Optical Interferometry with the CHARA Array

Cited by 15 publications

References 65 publications

ARMADA. I. Triple Companions Detected in B-type Binaries α Del and ν Gem

ARMADA. I. Triple Companions Detected in B-type Binaries α Del and ν Gem

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

Surveying the Bright Stars by Optical Interferometry. II. A Volume-limited Multiplicity Survey of Main-sequence F Stars

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