RenderableHabitableZone

Inherits Renderable

Represents a star’s habitable zone, with boundaries computed from its effective temperature and luminosity.

The inner and outer boundaries of the habitable zone are computed using formulas from Kopparapu et al. (2013) for an Earth-like rocky planet. The model defines both optimistic and conservative boundaries: the optimistic range includes regions where liquid water could exist (assuming Venus and Mars once had it), while the conservative range is more restrictive, indicating where stable surface liquid water is most likely under Earth-like conditions.

These formulas are valid for stars with effective temperatures between 2600–7200 K. Outside this range, a simpler method by Tom E. Harris is used, based only on stellar luminosity and without optimistic boundaries. For flexibility, the temperature interval for using Kopparapu’s formulas can be configured.

The habitable zone regions are visualized using the provided 1D Texture, divided into three equal parts: the center represents the conservative zone, the first part the optimistic inner zone, and the last part the optimistic outer zone (furthest from the star).

Members

Name	Documentation	Type	Description	Optional
EffectiveTemperature	The effective temperature of the corresponding star, in Kelvin. Used to compute the width and size of the disc.	Double	Greater or equal to: 0	No
Luminosity	The luminosity of the corresponding star, in units of solar luminosities. Used to compute the width and size of the disc.	Double	Greater or equal to: 0	No
Texture	The path to a file with a one-dimensional texture to be used for the disc color. The leftmost color will be innermost color when rendering the disc, and the rightmost color will be the outermost color.	File	Value of type ‘File’	No
DimInAtmosphere	Decides if the object should be dimmed (i.e. faded out) when the camera is in the sunny part of an atmosphere.	Boolean	Value of type ‘Boolean’	Yes
Enabled	Determines whether this object will be visible or not.	Boolean	Value of type ‘Boolean’	Yes
KopparapuTeffInterval	The effective temperature interval for which Kopparapu’s formula is used for the habitable zone computation. For stars with temperatures outside the range, a simpler method by Tom E. Harris is used. This method only uses the star luminosity and does not include computation of the optimistic boundaries.	Vector2<double>	Value of type ‘Vector2’	Yes
Opacity	This value determines the opacity of this renderable. A value of 0 means completely transparent.	Double	In range: ( 0, 1)	Yes
Optimistic	If true, the habitable zone disc is rendered with the optimistic boundaries rather than the conservative ones.	Boolean	Value of type ‘Boolean’	Yes
RenderBinMode	A value that specifies if the renderable should be rendered in the Background, Opaque, Pre-/PostDeferredTransparency, Overlay, or Sticker rendering step.	String	In list { Background, Opaque, PreDeferredTransparent, Overlay, PostDeferredTransparent, Sticker }	Yes
Size	The outer radius of the disc, in meters.	Double	Greater or equal to: 0	Yes
Tag	A single tag or a list of tags that this renderable will respond to when setting properties.	Table, or String	Value of type ‘Table’, or Value of type ‘String’	Yes
Type	The type of the renderable.	String	Value of type ‘String’	Yes
Width	The disc width, given as a ratio of the full disc radius. For example, a value of 1 results in a full circle, while 0.5 results in a disc where the inner radius is half of the full radius.	Double	In range: ( 0, 1)	Yes

Inherited members from Renderable

Name	Documentation	Type	Description	Optional
DimInAtmosphere	Decides if the object should be dimmed (i.e. faded out) when the camera is in the sunny part of an atmosphere.	Boolean	Value of type ‘Boolean’	Yes
Enabled	Determines whether this object will be visible or not.	Boolean	Value of type ‘Boolean’	Yes
Opacity	This value determines the opacity of this renderable. A value of 0 means completely transparent.	Double	In range: ( 0, 1)	Yes
RenderBinMode	A value that specifies if the renderable should be rendered in the Background, Opaque, Pre-/PostDeferredTransparency, Overlay, or Sticker rendering step.	String	In list { Background, Opaque, PreDeferredTransparent, Overlay, PostDeferredTransparent, Sticker }	Yes
Tag	A single tag or a list of tags that this renderable will respond to when setting properties.	Table, or String	Value of type ‘Table’, or Value of type ‘String’	Yes
Type	The type of the renderable.	String	Value of type ‘String’	Yes

Asset Examples

local transforms = asset.require("./transforms")
local textures = asset.require("scene/milkyway/habitable_zones/habitable_zone_textures")



local HabitableZone = {
  Identifier = "SunHabitableZone",
  Parent = transforms.SunEclipJ2000.Identifier,
  Renderable = {
    Type = "RenderableHabitableZone",
    Enabled = false,
    Texture = textures.TexturesPath .. "hot_to_cold_faded.png",
    EffectiveTemperature = 5780, -- Kelvin
    Luminosity = 1, -- solar
    Opacity = 0.1,
    Optimistic = true
  },
  GUI = {
    Name = "Sun's Habitable Zone",
    Path = "/Solar System/Sun",
    Focusable = false,
    Description = "Habitable zone for the sun in our solar system"
  }
}


asset.onInitialize(function()
  openspace.addSceneGraphNode(HabitableZone)
end)

asset.onDeinitialize(function()
  openspace.removeSceneGraphNode(HabitableZone)
end)

asset.export(HabitableZone)



asset.meta = {
  Name = "Sun Habitable Zone",
  Description = [[The habitable zone around our sun, computed using formula and
    coefficients by Kopparapu et al. (2015) https://arxiv.org/abs/1404.5292]],
  Author = "OpenSpace Team",
  URL = "https://openspaceproject.com",
  License = "MIT license"
}