Capabilities of future intensity interferometers for observing fast-rotating stars: imaging with two- and three-telescope correlations

Nuñez, Paul D.; Souza, A. Domiciano de

doi:10.1093/mnras/stv1719

Cited by 19 publications

(15 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such third-order measures are more sensitive to observational noise but, on the other hand, large telescope arrays permit many different three-telescope combinations to be electronically created. Such three-point correlations provide additional constraints that may enhance image reconstruction [33][34] . Also, fourth-and higher-order correlations may be constructed from quadruplets or larger groups of telescopes, the effort, in principle, being solely in software.…”

Section: Intensity Interferometry: Three or More Telescopesmentioning

confidence: 99%

Intensity interferometry: optical imaging with kilometer baselines

Dravins

2016

SPIE Proceedings

View full text Add to dashboard Cite

Optical imaging with microarcsecond resolution will reveal details across and outside stellar surfaces but requires kilometer-scale interferometers, challenging to realize either on the ground or in space. Intensity interferometry, electronically connecting independent telescopes, has a noise budget that relates to the electronic time resolution, circumventing issues of atmospheric turbulence. Extents up to a few km are becoming realistic with arrays of optical air Cherenkov telescopes (primarily erected for gamma-ray studies), enabling an optical equivalent of radio interferometer arrays. Pioneered by Hanbury Brown and Twiss, digital versions of the technique have now been demonstrated, reconstructing diffraction-limited images from laboratory measurements over hundreds of optical baselines. This review outlines the method from its beginnings, describes current experiments, and sketches prospects for future observations.

show abstract

Section: Intensity Interferometry: Three or More Telescopesmentioning

confidence: 99%

Intensity interferometry: optical imaging with kilometer baselines

Dravins

2016

SPIE Proceedings

View full text Add to dashboard Cite

show abstract

“…In the last fifteen years, researchers have been able to directly detect the oblate shapes of several rapidly-rotating, massive stars by means of optical and infrared interferometry (van Belle et al 2001;McAlister et al 2005;Monnier et al 2007;Zhao et al 2009;van Belle 2012). More direct detections are likely to be made in the future as observations continue to improve (Nuñez & Domiciano de Souza 2015).…”

Section: Introductionmentioning

confidence: 99%

Convection in Oblate Solar-Type Stars

Wang

Miesch

Liang

2016

ApJ

View full text Add to dashboard Cite

We present the first global 3D simulations of thermal convection in the oblate envelopes of rapidly-rotating solar-type stars. This has been achieved by exploiting the capabilities of the new Compressible High-ORder Unstructured Spectral difference (CHORUS) code. We consider rotation rates up to 85% of the critical (breakup) rotation rate, which yields an equatorial radius that is up to 17% larger than the polar radius. This substantial oblateness enhances the disparity between polar and equatorial modes of convection. We find that the convection redistributes the heat flux emitted from the outer surface, leading to an enhancement of the heat flux in the polar and equatorial regions. This finding implies that lower-mass stars with convective envelopes may not have darker equators as predicted by classical gravity darkening arguments. The vigorous high-latitude convection also establishes elongated axisymmetric circulation cells and zonal jets in the polar regions. Though the overall amplitude of the surface differential rotation, ∆Ω, is insensitive to the oblateness, the oblateness does limit the fractional kinetic energy contained in the differential rotation to no more than 61%. Furthermore, we argue that this level of differential rotation is not enough to have a significant impact on the oblateness of the star.

show abstract

“…Capability studies of SII on a CTA-like observatory demonstrate the ability to observe stellar targets brighter than a limiting visual magnitude of m V < 6 or 7 [27]. Science opportunities with a future CTA-SII observatory include surveying the angular diameter of stars larger than ∼ 0.05 mas at short visible wavelengths, measuring the orbital and stellar parameters of interacting binaries [28], characterizing the effects of gravity darkening and rotational deformation of rapidly rotating stars [29], and imaging of dark or hot star spots [27]. The VSII observations presented here demonstrate the core requirements for such an observatory, thus providing a technological pathway in addition to performing SII observations with unprecedented sensitivity.…”

mentioning

confidence: 99%

Demonstration of stellar intensity interferometry with the four VERITAS telescopes

et al. 2020

View full text Add to dashboard Cite

High angular resolution observations at optical wavelengths provide valuable insights in stellar astrophysics [1, 2], directly measuring fundamental stellar parameters [3, 4], and probing stellar atmospheres, circumstellar disks [5], elongation of rapidly rotating stars [6], and pulsations of Cepheid variable stars [7]. The angular size of most stars are of order one milli-arcsecond or less, and to spatially resolve stellar disks and features at this scale requires an optical interferometer using an array of telescopes with baselines on the order of hundreds of meters. We report on the successful implementation of a stellar intensity interferometry system developed for the four VERITAS imaging atmospheric-Cherenkov telescopes. The system was used to measure the angular diameter of the two sub-mas stars β Canis Majoris and Orionis with a precision better than 5%. The system utilizes an off-line approach where starlight intensity fluctuations recorded at each telescope are correlated post-observation. The technique can be readily scaled onto tens to hundreds of telescopes, providing a capability that has proven technically challenging to current generation optical amplitude interferometry observatories. This work demonstrates the feasibility of performing astrophysical measurements with imaging atmospheric-Cherenkov telescope arrays as intensity interferometers and the promise for integrating an intensity interferometry system within future observatories such as the Cherenkov Telescope Array.

show abstract

Capabilities of future intensity interferometers for observing fast-rotating stars: imaging with two- and three-telescope correlations

Cited by 19 publications

References 26 publications

Intensity interferometry: optical imaging with kilometer baselines

Intensity interferometry: optical imaging with kilometer baselines

Convection in Oblate Solar-Type Stars

Demonstration of stellar intensity interferometry with the four VERITAS telescopes

Contact Info

Product

Resources

About