[Paper Review] Science opportunities enabled by the era of Visible Band Stellar Imaging with sub-100 μarc-sec angular resolution

D. Kieda, M. Vázquez Acosta+9 more|arXiv (Cornell University)|Aug 8, 2019

Stellar, planetary, and galactic studies4 citations

TL;DR

This white paper outlines transformative science opportunities enabled by sub-100 μarc-sec angular resolution in the visible band using next-generation Imaging Cherenkov telescopes via Stellar Intensity Interferometry (SII). The method enables ultra-high-resolution imaging of bright, hot O/B/A stars, unlocking new insights into stellar structure, dynamics, and environments at unprecedented detail.

ABSTRACT

This white paper briefly summarizes stellar science opportunities enabled by ultra-high resolution (sub-100 μ arc-sec) astronomical imaging in the visible (U/V) wavebands. Next generation arrays of Imaging Cherenkov telescopes, to be constructed in the next decade, can provide unprecedented visible band imaging of several thousand bright (m< 6), hot (O/B/A) stars using a modern implementation of Stellar Intensity Interferometry (SII). This white paper describes the astrophysics/astronomy science opportunities that may be uncovered in this new observation space during the next decade.

Motivation & Objective

• To identify and articulate new astrophysical science opportunities enabled by ultra-high angular resolution (sub-100 μarc-sec) visible band imaging of stars.
• To demonstrate how next-generation Imaging Cherenkov telescope arrays can achieve visible-band stellar imaging using Stellar Intensity Interferometry (SII).
• To position SII as a viable, high-resolution alternative to traditional optical interferometry for bright, hot stars.
• To support the case for investment in visible-band SII instrumentation within the Astro2020 decadal survey framework.
• To explore the potential of SII to resolve stellar surfaces and environments at angular scales previously inaccessible to ground-based optical astronomy.

Proposed method

• Leverage next-generation Imaging Cherenkov telescope arrays to detect intensity correlations in light from bright stars (m < 6, O/B/A types).
• Implement a modern, scalable version of Stellar Intensity Interferometry (SII) that uses photon correlation techniques to achieve sub-100 μarc-sec resolution.
• Utilize the high time-resolution and sensitivity of Cherenkov telescopes to measure intensity fluctuations across multiple baselines.
• Apply statistical and interferometric analysis to reconstruct high-dynamic-range stellar intensity patterns in the visible band.
• Integrate data from multiple telescopes to synthesize aperture-synthesis-like images with angular resolution below 100 μarc-sec.
• Validate the method’s feasibility through simulations and theoretical modeling of stellar intensity patterns for hot, compact stars.

Experimental results

Research questions

• RQ1 What astrophysical phenomena can be resolved with sub-100 μarc-sec angular resolution in the visible band using SII?
• RQ2 How can SII provide high-resolution imaging of bright, hot stars without the limitations of traditional optical interferometry?
• RQ3 What new insights into stellar surface structures, rotation, and multiplicity can be gained from visible-band intensity interferometry?
• RQ4 What is the potential of SII to resolve circumstellar environments and mass-loss structures around O/B/A stars?
• RQ5 How do the sensitivity and dynamic range of SII compare to existing and planned optical interferometers for stellar studies?

Key findings

• Sub-100 μarc-sec resolution in the visible band enables direct imaging of stellar surfaces and close binary systems of O/B/A stars with unprecedented detail.
• Stellar Intensity Interferometry (SII) using Imaging Cherenkov telescopes can achieve angular resolutions below 100 μarc-sec, rivaling space-based optical interferometers.
• The method is particularly suited for bright, hot stars (m < 6), allowing high signal-to-noise intensity correlation measurements over long baselines.
• SII can resolve stellar limb darkening, rotation broadening, and surface inhomogeneities in massive stars, providing new constraints on stellar models.
• The technique opens a new observational window for studying circumstellar envelopes, mass-loss features, and binary star systems in the visible spectrum.
• The combination of high time resolution and wide field-of-view in Cherenkov arrays enables dynamic monitoring of stellar intensity fluctuations at micro-arcsecond scales.