Difference between revisions of "Kerbol"
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{{Infobox/Body}} | {{Infobox/Body}} | ||
| − | '''Kerbol''' | + | '''Kerbol''', A.K.A. the Sun, is the parent star of the '''[[Kerbol System]]''', making it the core of the explorable [[w:Planetary system|planetary system]] in [[KSP1]], as well as the first explorable planetary system in [[KSP2]]. Five planets: '''[[Moho]]''', '''[[Eve]]''', '''[[Kerbin]]''', '''[[Duna]]''' and '''[[Jool]]'''; and two dwarf planets: '''[[Dres]]''' and '''[[Eeloo]]'''; orbit around it. Kerbol contains 99.97% of the mass in the Kerbol system. This is very similar to our sun which contains 99.86% of the mass in the real world solar system. |
| − | + | "Kerbol" was originally a fan-made portmanteau of "Kerbal" and "Sol" — the Latin name for the real-life [[w:Sun|Sun]]. Before {{version|0.11}} of KSP1, which introduced an object for Kerbin's parent star and an orbital [[Map view]] where it was explicitly named, it was an unnamed directional light source at infinite distance. Fans on the KSP forums invented and popularized the name, and the term "Kerbol System" was used in the official 1.2 release post, the first issue of "The Kerbal Chronicles" as well as in the official trailer for the KSP Enhanced Edition. Doing an ice chunk analysis on Eeloo can confirm this name in KSP1. In KSP2, the star is explicitly named "Kerbol". | |
| − | |||
| − | |||
| + | == In-game description == | ||
{{Quote | {{Quote | ||
| + | |The Sun is the most well known object in the daytime sky. Scientists have noted a particular burning sensation and potential loss of vision if it is stared at for long periods of time. This is especially important to keep in mind considering the effect shiny objects have on the average Kerbal. | ||
| + | |[[Kerbal Astronomical Society]]}} | ||
| − | + | == Gravitational influence == | |
| − | + | Escaping the SOI of any other body will place an object in orbit around the Sun (Kerbol). This will give a [[Science]] situation of being in space high over the Sun (Kerbol) until an altitude less than 1,000 Mm is reached. Low orbit can be reached by using a standard [[Tutorial: Advanced Orbiting#Hohmann transfer|Hohmann transfer]] from [[Kerbin]]'s orbit, this requires about 8 km/s of change-in-velocity (Δv). The more efficient way to reach low Sun (Kerbol) orbit, at the expense of drastically increased flight time, is to use a [[Tutorial: Advanced Orbiting#Bi-elliptical transfer|bi-elliptical transfer]]. With a sufficiently-distant apoapsis, the required Δv to "sundive" from Kerbin orbit can be reduced to under 4 km/s. | |
| − | |||
| − | |||
| − | == | ||
| − | Escaping the SOI of any other body will place an object in orbit around Kerbol. This will give a [[Science]] situation of being in space high over Kerbol until an altitude less than 1,000 Mm is reached. Low orbit can be reached by using a standard [[Tutorial: Advanced Orbiting#Hohmann transfer|Hohmann transfer]] | ||
| − | + | Previously the closest sustained altitude was 1,340 m, but now bodies emit radiation which heats parts and overheats parts before it could reach the atmosphere. The heating varies on the surface area it shines and part specific heat. Using parts with higher maximum temperature reduces the chance of [[overheating]], making the inflatable heat shield a good choice to shield your delicate parts from heat. This imposes a challenge where the objective is to get as close to the Sun as possible while surviving. | |
| − | The [[sphere of influence]] (SOI) of Kerbol is infinite, making Kerbol inescapable. Thus, achieving gravitation-free flight is impossible | + | The [[sphere of influence]] (SOI) of the Sun (Kerbol) is infinite, making the Sun (Kerbol) inescapable. Thus, achieving gravitation-free flight is impossible. With a powerful enough ship, it is possible to get to the point where the info tab will display the craft's situation as "escaping" the Sun (Kerbol). The end of the patched conics path plotted by the game can be reached, at which point the spacecraft begins drawing a course behind it. But the actual escape never occurs. Presumably, this state would continue indefinitely, as the time required to find out what would happen would take several years real-time even at maximum time acceleration. |
=== Landing === | === Landing === | ||
| − | + | Similar to [[Jool]], it's impossible to land on the Sun. Any objects are destroyed at an altitude below -250 m, which shows in the end flight dialog as "crashed into the surface of the sun" or similar, rather than ever landing. | |
| − | One can attempt to place edited parts on the surface, but they bounce erratically at a few hundred to a few thousand meters | + | One can attempt to place edited parts on the surface, but they bounce erratically at a few hundred to a few thousand meters per second if they do not explode. |
| − | == Temperature and | + | == Temperature and luminosity == |
| − | [[File:Kerbol_temperature.png|thumbnail|left|Temperature-height profile of Kerbol's | + | [[File:Kerbol_temperature.png|thumbnail|left|Temperature-height profile of Kerbol's atmosphere.]] |
| − | Kerbol | + | The Sun's (Kerbol's) visible surface, its [[w:Photosphere|photosphere]], has a temperature of 5840 K. This temperature, along with the star's yellow color, suggests that the Sun (Kerbol) is a [[w:G-type_main-sequence_star|Class G main-sequence star]]. Above the photosphere is a thin and hot atmosphere that is analogous to a [[w:Chromosphere|chromosphere]]. The chromosphere extends to a height of 600 km and has at its base a pressure of 16 kPa. The temperature of the chromosphere decreases with increasing altitude until reaching a minimum of 4000 K at a height of 50 km. Above 50 km the temperature increases with increasing altitude. The maximum temperature of 10,000 K is reached at the atmosphere's extreme upper limit. |
| − | Based on its given size and temperature, Kerbol’s luminosity would be 56.7 yottawatts, however this is contradicted by other in-game physical parameters. | + | Based on its given size and temperature, the Sun's (Kerbol’s) luminosity would be 56.7 yottawatts, however this is contradicted by other in-game physical parameters. The value of the solar constant at Kerbin is 1360 W/m<sup>2</sup>, which implies a solar luminosity of 3.16 yottawatts (0.008 Solar luminosities) and a surface temperature of 2840 K. These values are consistent with a [[w:Red dwarf|Class M red dwarf]]. |
== Physical appearance == | == Physical appearance == | ||
| − | The equatorial radius of | + | The equatorial radius of the Sun is almost four times than that of Jupiter and 43.6 times larger than Jool's, the largest planet known in the Solar (Kerbol) system. <!-- Jupiter's radius is about 67 000 km, the Sun's (Kerbol's) radius is about 3.8 times greater --> the Sun (Kerbol) has the yellow color of a [[w:G-type_main-sequence_star|Class G main-sequence star]] and its [[w:Absolute_magnitude|absolute bolometric magnitude]] is approximately +10. If close enough, one can see that the [[w:Sunspot|dark spots]] are indented. |
| − | The | + | The "corona" surrounding the Sun (Kerbol) is not the actual size of the sun as it appears. It will shrink and grow relative to the location of the viewpoint, just as the size of Kerbol does normally. However, it won't shrink past a certain point, and if the sun is viewed from a far enough point, the corona is still very visible. This is apparent when using camera or telescope [[mods]] that remove the corona and show the Sun's (Kerbol's) true size, which is usually much smaller than the corona appears. |
=== Past appearances === | === Past appearances === | ||
[[File:Kerbol.jpg|thumbnail|left|Prior to {{version|0.11}} there was only a nameless light in space.]] | [[File:Kerbol.jpg|thumbnail|left|Prior to {{version|0.11}} there was only a nameless light in space.]] | ||
{{Version|0.7.3}} introduced the parent star of Kerbin as a slightly red-tinted directional light (with lots of lens flare) in the skybox at infinite distance, thus impossible to reach. | {{Version|0.7.3}} introduced the parent star of Kerbin as a slightly red-tinted directional light (with lots of lens flare) in the skybox at infinite distance, thus impossible to reach. | ||
| − | [[File:KerbolSurface.png|thumbnail|Surface in {{version|0.17}}.]]In {{version|0.11}}, it became a yellow sphere which could be visited but its surface wasn't solid. It was named | + | [[File:KerbolSurface.png|thumbnail|Surface in {{version|0.17}}.]] |
| + | In {{version|0.11}}, it became a yellow sphere which could be visited but its surface wasn't solid. It was named "The Sun" in Map view; however, fans had already taken to calling the star "Kerbol". Up to {{version|0.13.3}} dropping below the "surface" was still safe, but a ship could break up from the extreme gravity gradients and/or be shot outwards at large fractions of the speed of light. | ||
| − | == Reference | + | == Reference frames == |
{{:Kerbol/RefFrame}} | {{:Kerbol/RefFrame}} | ||
| − | |||
== Trivia == | == Trivia == | ||
| − | * The | + | * The Sun has just under twice the surface gravity of Kerbin, thus only slightly more than Eve's. |
| − | + | * The Kerbal Sun is not a realistic analogue of our Real Sun. | |
| − | + | ** The Mun is larger and closer to Kerbin than Moon to Earth, and thus in order to make eclipses work right, the Sun was made large enough to fit. | |
=== Real-world comparison === | === Real-world comparison === | ||
| − | While otherwise analogous to our own real-life [[w:Sun|Sun]], Kerbol has 1/113<sup>th</sup> the mass and | + | While otherwise analogous to our own real-life [[w:Sun|Sun]], the Sun (Kerbol) has 1/113<sup>th</sup> the mass and 1/3<sup>rd</sup> its radius. The Sun's (Kerbol's) other attributes can be used to derive the following statistics: it has a luminosity of approximately 3 yottawatts based on the solar constant at Kerbin; a defined surface temperature of 5840 K (that of a [[w:Stellar_classification#Class_G|Class G star]]), but a temperature less than 3000 K based on its size and luminosity (that of a [[w:Stellar_classification#Class_M|Class M star]]); the radius of a [[w:Red dwarf|red dwarf]]; and the mass of a [[w:Sub-brown dwarf|sub-brown dwarf]]. Such a star in real life would be on the limits of Hydrostatic equilibrium and its small size would mean it would only generate as much heat as a red dwarf. However, many astrophysical properties in KSP are effectively scaled down for gameplay. |
| + | |||
| + | Its real-life counterpart according to its size and mass would be [https://en.wikipedia.org/wiki/2MASS_J0523-1403 2MASS J0523-1403], the smallest star currently known. | ||
== Gallery == | == Gallery == | ||
| + | === [[Kerbal Space Program]] === | ||
<gallery> | <gallery> | ||
| − | |||
KerbolSurface.png | A picture taken of a probe on a close encounter with Kerbol shortly before overheating. | KerbolSurface.png | A picture taken of a probe on a close encounter with Kerbol shortly before overheating. | ||
| − | Kerbol17.png | + | Kerbol17.png | Up close the lens flare becomes evidently [[w:Nonagon|ennagonal]]. |
| − | + | Kerbolterrain.png | Elevation shown on Kerbol | |
| − | + | Close approach to Sun.png | A close flyby of Kerbol | |
</gallery> | </gallery> | ||
== Changes == | == Changes == | ||
| − | + | === [[Kerbal Space Program]] === | |
| + | ;[[1.3]] | ||
| + | * Changed displayName to The Sun, removed useTheInName = true feature. | ||
;[[1.0]] | ;[[1.0]] | ||
| − | Added atmosphere | + | * Added an atmosphere. |
;[[0.18.2]] | ;[[0.18.2]] | ||
* Art pass. | * Art pass. | ||
| Line 75: | Line 76: | ||
* Added Gravity, nominal radius of 65,400 km. | * Added Gravity, nominal radius of 65,400 km. | ||
;[[0.11]] | ;[[0.11]] | ||
| − | * Made it possible to reach Kerbol. | + | * Made it possible to reach the Sun (Kerbol). |
;[[0.7.3]] | ;[[0.7.3]] | ||
* Initial Release. | * Initial Release. | ||
| + | |||
| + | === [[Kerbal Space Program 2]] === | ||
| + | ;0.1.1 | ||
| + | * Fixed description for Kerbol capture and Kerbosationary orbit trip stages in trip planner. | ||
| + | * Improved Kerbol flare/bloom effects. | ||
| + | ;0.1.0 | ||
| + | * Initial release. | ||
{{Celestial Bodies}} | {{Celestial Bodies}} | ||
[[Category:Celestials]] | [[Category:Celestials]] | ||
Latest revision as of 01:50, 15 July 2023
| Kerbol | ||
 | ||
| Kerbol as seen from orbit. | ||
| Star | ||
| Physical Characteristics | ||
| Equatorial radius | 261 600 000 m | |
| Equatorial circumference | 1 643 681 276 m | |
| Surface area | 8.5997404×1017 m2 | |
| Mass | 1.7565459×1028 kg | |
| Standard gravitational parameter | 1.1723328×1018 m3/s2 | |
| Density | 234.23818 kg/m3 | |
| Surface gravity | 17.1 m/s2 (1.747 g) | |
| Escape velocity | 94 672.01 m/s | |
| Sidereal rotation period | 432 000.00 s | |
| 20 d 0 h 0 m 0 s | ||
| Sidereal rotational velocity | 3 804.8 m/s | |
| Synchronous orbit | 1 508 045.29 km | |
| Sphere of influence | ∞ | |
| Atmospheric Characteristics | ||
| Atmosphere present | Yes | |
| Atmospheric pressure | 16.0000 kPa | |
| 0.157908 atm | ||
| Atmospheric height | 600 000 m | |
| 1.6×10-7 atm | ||
| Temperaturemin | 3741.80 °C 4014.95 K | |
| Temperaturemax | 9348.05 °C 9621.2 K | |
| Oxygen present | No | |
| Scientific multiplier | ||
| Surface | N/A | |
| Splashed | N/A | |
| Lower atmosphere | 1 | |
| Upper atmosphere | 1 | |
| Near space | 11 | |
| Outer space | 2 | |
| Recovery | 4 | |
Kerbol, A.K.A. the Sun, is the parent star of the Kerbol System, making it the core of the explorable planetary system in KSP1, as well as the first explorable planetary system in KSP2. Five planets: Moho, Eve, Kerbin, Duna and Jool; and two dwarf planets: Dres and Eeloo; orbit around it. Kerbol contains 99.97% of the mass in the Kerbol system. This is very similar to our sun which contains 99.86% of the mass in the real world solar system.
"Kerbol" was originally a fan-made portmanteau of "Kerbal" and "Sol" — the Latin name for the real-life Sun. Before version 0.11 of KSP1, which introduced an object for Kerbin's parent star and an orbital Map view where it was explicitly named, it was an unnamed directional light source at infinite distance. Fans on the KSP forums invented and popularized the name, and the term "Kerbol System" was used in the official 1.2 release post, the first issue of "The Kerbal Chronicles" as well as in the official trailer for the KSP Enhanced Edition. Doing an ice chunk analysis on Eeloo can confirm this name in KSP1. In KSP2, the star is explicitly named "Kerbol".
Contents
In-game description
| “ | The Sun is the most well known object in the daytime sky. Scientists have noted a particular burning sensation and potential loss of vision if it is stared at for long periods of time. This is especially important to keep in mind considering the effect shiny objects have on the average Kerbal. | ” |
Gravitational influence
Escaping the SOI of any other body will place an object in orbit around the Sun (Kerbol). This will give a Science situation of being in space high over the Sun (Kerbol) until an altitude less than 1,000 Mm is reached. Low orbit can be reached by using a standard Hohmann transfer from Kerbin's orbit, this requires about 8 km/s of change-in-velocity (Δv). The more efficient way to reach low Sun (Kerbol) orbit, at the expense of drastically increased flight time, is to use a bi-elliptical transfer. With a sufficiently-distant apoapsis, the required Δv to "sundive" from Kerbin orbit can be reduced to under 4 km/s.
Previously the closest sustained altitude was 1,340 m, but now bodies emit radiation which heats parts and overheats parts before it could reach the atmosphere. The heating varies on the surface area it shines and part specific heat. Using parts with higher maximum temperature reduces the chance of overheating, making the inflatable heat shield a good choice to shield your delicate parts from heat. This imposes a challenge where the objective is to get as close to the Sun as possible while surviving.
The sphere of influence (SOI) of the Sun (Kerbol) is infinite, making the Sun (Kerbol) inescapable. Thus, achieving gravitation-free flight is impossible. With a powerful enough ship, it is possible to get to the point where the info tab will display the craft's situation as "escaping" the Sun (Kerbol). The end of the patched conics path plotted by the game can be reached, at which point the spacecraft begins drawing a course behind it. But the actual escape never occurs. Presumably, this state would continue indefinitely, as the time required to find out what would happen would take several years real-time even at maximum time acceleration.
Landing
Similar to Jool, it's impossible to land on the Sun. Any objects are destroyed at an altitude below -250 m, which shows in the end flight dialog as "crashed into the surface of the sun" or similar, rather than ever landing.
One can attempt to place edited parts on the surface, but they bounce erratically at a few hundred to a few thousand meters per second if they do not explode.
Temperature and luminosity
The Sun's (Kerbol's) visible surface, its photosphere, has a temperature of 5840 K. This temperature, along with the star's yellow color, suggests that the Sun (Kerbol) is a Class G main-sequence star. Above the photosphere is a thin and hot atmosphere that is analogous to a chromosphere. The chromosphere extends to a height of 600 km and has at its base a pressure of 16 kPa. The temperature of the chromosphere decreases with increasing altitude until reaching a minimum of 4000 K at a height of 50 km. Above 50 km the temperature increases with increasing altitude. The maximum temperature of 10,000 K is reached at the atmosphere's extreme upper limit.
Based on its given size and temperature, the Sun's (Kerbol’s) luminosity would be 56.7 yottawatts, however this is contradicted by other in-game physical parameters. The value of the solar constant at Kerbin is 1360 W/m2, which implies a solar luminosity of 3.16 yottawatts (0.008 Solar luminosities) and a surface temperature of 2840 K. These values are consistent with a Class M red dwarf.
Physical appearance
The equatorial radius of the Sun is almost four times than that of Jupiter and 43.6 times larger than Jool's, the largest planet known in the Solar (Kerbol) system. the Sun (Kerbol) has the yellow color of a Class G main-sequence star and its absolute bolometric magnitude is approximately +10. If close enough, one can see that the dark spots are indented.
The "corona" surrounding the Sun (Kerbol) is not the actual size of the sun as it appears. It will shrink and grow relative to the location of the viewpoint, just as the size of Kerbol does normally. However, it won't shrink past a certain point, and if the sun is viewed from a far enough point, the corona is still very visible. This is apparent when using camera or telescope mods that remove the corona and show the Sun's (Kerbol's) true size, which is usually much smaller than the corona appears.
Past appearances
version 0.7.3 introduced the parent star of Kerbin as a slightly red-tinted directional light (with lots of lens flare) in the skybox at infinite distance, thus impossible to reach.
In version 0.11, it became a yellow sphere which could be visited but its surface wasn't solid. It was named "The Sun" in Map view; however, fans had already taken to calling the star "Kerbol". Up to version 0.13.3 dropping below the "surface" was still safe, but a ship could break up from the extreme gravity gradients and/or be shot outwards at large fractions of the speed of light.
Reference frames
| Time warp | Minimum Altitude |
|---|---|
| 1× | Any |
| 5× | 3 270 000 m |
| 10× | 3 270 000 m |
| 50× | 6 540 000 m |
| 100× | 13 080 000 m |
| 1 000× | 26 160 000 m |
| 10 000× | 52 320 000 m |
| 100 000× | 65 400 000 m |
Trivia
- The Sun has just under twice the surface gravity of Kerbin, thus only slightly more than Eve's.
- The Kerbal Sun is not a realistic analogue of our Real Sun.
- The Mun is larger and closer to Kerbin than Moon to Earth, and thus in order to make eclipses work right, the Sun was made large enough to fit.
Real-world comparison
While otherwise analogous to our own real-life Sun, the Sun (Kerbol) has 1/113th the mass and 1/3rd its radius. The Sun's (Kerbol's) other attributes can be used to derive the following statistics: it has a luminosity of approximately 3 yottawatts based on the solar constant at Kerbin; a defined surface temperature of 5840 K (that of a Class G star), but a temperature less than 3000 K based on its size and luminosity (that of a Class M star); the radius of a red dwarf; and the mass of a sub-brown dwarf. Such a star in real life would be on the limits of Hydrostatic equilibrium and its small size would mean it would only generate as much heat as a red dwarf. However, many astrophysical properties in KSP are effectively scaled down for gameplay.
Its real-life counterpart according to its size and mass would be 2MASS J0523-1403, the smallest star currently known.
Gallery
Kerbal Space Program
A picture taken of a probe on a close encounter with Kerbol shortly before overheating.
Up close the lens flare becomes evidently ennagonal.
Elevation shown on Kerbol
A close flyby of Kerbol
Changes
Kerbal Space Program
- Changed displayName to The Sun, removed useTheInName = true feature.
- Added an atmosphere.
- Art pass.
- Actual model added, new sprite/flare effect, size changed.
- Added solid surface (featureless invisible plateau ~4500–4700 km above nominal radius).
- Added Gravity, nominal radius of 65,400 km.
- Made it possible to reach the Sun (Kerbol).
- Initial Release.
Kerbal Space Program 2
- 0.1.1
- Fixed description for Kerbol capture and Kerbosationary orbit trip stages in trip planner.
- Improved Kerbol flare/bloom effects.
- 0.1.0
- Initial release.
