Event-horizon silhouette
A central dark sphere marks the compact-object boundary scale. It is visually enlarged relative to the surrounding system so the scene can be studied on a screen.
Black-hole field guide
A0620-00 as a compact-object study target.
A close binary with a low-mass companion feeding a compact black hole during outbursts.
A0620-00 - Nearby stellar black-hole binary
Catalog identity
Observed and inferred properties
Observation basis
How the black hole is inferred
Mass comes from binary orbital dynamics and emission signatures after historical X-ray eruptions.
Useful as a nearby stellar-black-hole scale benchmark, not a spectacular naked-eye target.
Simulation Layers
What the WebGL scene shows
Photon-ring cue
The bright ring is a lensing-inspired visual layer that explains why near-horizon light can wrap around the compact object.
Accretion flow
Rotating disk particles show hot gas losing angular momentum. Disk color and thickness vary by black-hole class.
Jets and outflows
Targets with active nuclei or microquasar behavior show collimated jet cones; quiet/dormant targets omit the jet layer.
Scale compression
The model compresses event-horizon, disk, binary, galaxy, and light-year scales into a readable study frame.
Main simulator
The object is also selectable from the 3D Space Lab deep-space focus list.
Physics explanation
What controls the appearance
Black holes are observed by their influence: gravity, accretion, jets, hot gas spectra, stellar motion, binary dynamics, and lensing. The visible dark center is not a surface. It is a one-way causal boundary surrounded by curved spacetime and, when fuel is present, rapidly orbiting plasma.
Review caution
What not to over-read
Small compact disk and donor-star stream emphasize close-binary mass-transfer physics.
The visualization is deliberately lightweight for public web performance. It is a physics-oriented diagram in 3D, not a general-relativistic magnetohydrodynamics simulation or a direct telescope image.
Mathematical model
Black-hole and accretion-disk model
Black-hole visuals use theoretical scaling equations for the event horizon, photon-ring marker, and optically thick accretion disk. They are educational WebGL approximations, not numerical general-relativistic ray-tracing renders.
Event-horizon scale
\[R_s=\frac{2GM}{c^2}\]
The black silhouette is scaled from the Schwarzschild radius relation. Mass changes the horizon scale through G, M, and c, not through image tracing.
Thin-disk temperature
\[T(r)^4 \propto r^{-3}\left[1-\sqrt{\frac{R_{\mathrm{in}}}{r}}\right]\]
The annular disk brightness and color are assigned from the standard steady thin-disk radial profile, so inner rings are hotter and outer rings cool by equation.
Keplerian disk flow
\[\Omega(r)=\sqrt{\frac{GM}{r^3}}\]
Orbiting gas is represented as differentially rotating annuli and flow bands. The visual proof is that angular speed decreases with radius as Keplerian motion requires.
Verification standard: the rendered object must be reproducible from stated equations, catalog parameters, or explicit geometric transforms. Visual reference images may inform presentation only; they are not the source of orbital positions, field vectors, accretion-disk gradients, timing, or engineering layout.
Limitations: browser scenes may use bounded scale, compressed distances, simplified two-body dynamics, schematic transfer curves, or educational approximations where full numerical ephemerides, CFD, finite-element models, or general-relativistic ray tracing are outside the page scope. Those simplifications are part of the model contract, not hidden image-based construction.