STELLAR FATES / EXPLORER GUIDE

How to use
Stellar Fates.

Start with one star, then explore what changes when it has a companion. This guide follows the controls in the explorer.

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START HERE

Your first stellar life.

Choose Single star, then select the Sun-like / 1 M☉ preset.
Select Play life cycle. Watch the star change while its age appears beneath the view.
Select Pause life cycle to examine a stage. Drag to rotate, then use the + button or a two-finger pinch to zoom closer.

Next, try Massive / 15 M☉. The massive-star menu becomes available, letting you compare three illustrated endings.

01 / ONE STAR

Single star and starting mass.

Use the Star A / starting mass slider, or enter a number in the box beside it and press Enter or leave the box. The range is 0.8 to 40 M☉. One solar mass, written M☉, is the mass of our Sun.

The four presets choose 1, 5, 15, or 30 solar masses. A higher starting mass generally gives a shorter hydrogen-burning lifetime in this illustration. Changing the mass restarts the timeline so you can follow the story from its beginning.

Below 8 M☉, this explorer follows envelope loss and a white dwarf. The massive-star menu is disabled because this selected story already has its ending. The boundary belongs to this simplified illustration; real stars do not follow a single exact mass rule.

02 / CHOOSE AN ENDING

Massive-star illustration.

This menu becomes active for a single star of at least 8 M☉, or a wide binary containing at least one such star. Choose an outcome, then play the story again. These are possible endings to compare, rather than a prediction based on starting mass alone.

Supernova → neutron star: The core contracts, an explosion sends material outward, and an enlarged neutron star remains with sweeping beams.
Supernova → black hole: An explosion is followed by a black-hole remnant. Bent disk light and inward-moving gas illustrate a possible surrounding flow.
Quiet collapse → black hole: The core contracts without the bright supernova flash. Darkness forms shows the fading core and a settling cloud as the disk is revealed. Black hole shows the cleared remnant.

In a wide pair, the selected ending applies to each massive star. A lower-mass companion still follows the white-dwarf story. In either guided binary story, this menu is disabled because that story has its own ending.

03 / ADD A COMPANION

Binary system and Binary story.

Select Binary system to see two stars, their stage readouts, the starting separation, and the Binary story menu. Choose one of these three stories:

Wide pair / choose two masses: Set Star A and Star B independently, from 0.8 to 40 M☉ each. Both share one age. Try A = 15 and B = 1 to see the larger star reach its remnant while the smaller one is still burning hydrogen. The heavier star follows the smaller orbit around their shared center.
Guided pair / envelope transfer: This story fixes the starting masses at A = 5 and B = 3 M☉, so the mass controls are disabled. Follow gas leaving A and reaching B. The chosen example finishes with A as a white dwarf, B at 5 M☉, and 2 M☉ outside the pair. The mass-budget readout shows where the material went.
Guided pair / white-dwarf explosion: This story begins with an existing 1.1 M☉ white dwarf and a 2 M☉ giant. The starting masses are fixed. The dwarf gains gas and is destroyed in the illustrated thermonuclear event, leaving no compact remnant at its position. The companion remains.

What does Starting separation change?

Separation is measured in AU; one AU is Earth’s average distance from the Sun. The range is 20–120 AU for the wide pair and 0.5–2 AU for guided pairs. Changing it adjusts the illustrated spacing and initial orbital period, while keeping your place in the timeline. It does not switch a wide pair into a transfer story or determine whether a real pair merges.

Changing the mode, mass, selected ending, or binary story restarts playback at the beginning. Single-star and binary settings are kept separately while you stay in the explorer.

04 / FOLLOW THE SCENE

Playback, rotation, and zoom.

Play life cycle / Pause life cycle: Advance or stop the story’s timeline. Replay starts it again from the beginning.
Move through the story: Drag the timeline slider to any point, or select a named stage below it. Either action pauses the timeline at your chosen point.
Rotate and zoom: On a computer, drag inside the view to rotate; use the mouse wheel or + and − to zoom. On a phone, drag with one finger to rotate and pinch with two fingers to zoom. The + and − buttons work on both.
Whole scene / Inspect A / Inspect B: Focus on the pair or move closer to one star. Inspect B is available in binary mode. The ↺ button at the upper right resets the camera view.
Ambient motion: Turn off this checkbox to stop decorative motion such as the orbit, gas flow, and sweeping beams. Pausing the life cycle alone can leave that motion running. With ambient motion off, Play still advances the star’s life stages.
Keyboard: Click or tab into the main view, then use the arrow keys to rotate and + or − to zoom. Tab also moves between the buttons, sliders, and menus.

05 / THE YEARS BENEATH THE VIEW

Reading the clock.

≈ means approximately. In single-star mode, the clock starts when core hydrogen burning begins; the formation prelude has no assigned age. The wide pair uses one shared age. The guided white-dwarf explosion uses elapsed time within its assumed transfer story, rather than the white dwarf’s age since birth.

The replay slows short events and compresses long ones. A position of 70% means 70% through this replay, rather than 70% of the star’s lifespan. The initial orbital period is a separate readout, and orbit motion is accelerated for viewing.

Stellar sizes, remnant sizes, and gas flow are illustrated to make the stages visible. The chosen outcomes and guided transfer histories help you compare ideas; they are not forecasts for a particular star. For the scientific assumptions and source records, open About the illustration.