Main Sequence F Type Stars - Habitable Simulation

The F-Type Stars described here are Main Sequence Stars on The H-R Diagram. They are brighter then the Sun but in many aspects similar to it. They are subdivided from F0 to F9. This article is based on data available from [www.pas.rochester.edu/~emamajek/EEM_dwarf_UBVIJHK_colors_Teff.txt here]. Additional parameters are calculated using the black body radiation formulas available at Math And Terraforming.

It is very important to remember that stars don't behave exactly as shown in the table. Each star has its own variations. Also, my calculations are based on the black body radiation formulas and they do not include flares and the Stellar Wind.

For each star model, parameters are compared to our own sun, Sol.

This article is dedicated for sci-fi writers, to have a better and close-up idea if a planet around a certain star can indeed be terraformed or not and at what cost. Please don't take it as a scientific work, it is just a simulation made with values that are much more easy to understand then dedicated scientific papers.

About the values[]

For all stars, the following parameters are calculated:

Main parameters:

Temperature (in degrees K, for our Sun, Sol it is 5778 K).
Mass: given in Solar masses
Radius: given in Solar radii
Bolometric Magnitude: includes all star's radiation, for Sol it is 4.81.
Visual magnitude: includes only visual light, for Sol it is 4.81.

Spectral parameters:

Main light spectra (for Sol, it is 577 nm). It helps us see if most light is emitted in red, blue, infrared or ultraviolet spectra.

Solar Constant - total energy output of the star: (Sol = 1)
Infrared light: (Sol = 1)
Red light: (Sol = 1)
Visible light: (Sol = 1)
Blue light: (Sol = 1)
Ultraviolet light: (Sol = 1)
Far UV light: (Sol = 1)

Habitable zone, based on light emissions:

Calculating the habitable zone, one must include four parameters:

Roche limit - below it, a star's gravity would tear apart any planet;
Solar constant - depends on distance from the star. For Earth, it is 1. Using Greenhouse Gases, it is possible to terraform a planet with a solar constant of 1/1000. By using Anti-Greenhouse Technology, it might be possible to terraform a planet with a solar constant of 20.
Light spectra - Plants on New Worlds need both red and blue light, which must be at least 1/1000 of what is on Earth. If either red or blue light fall below this limit, plants will not survive.
Toxic radiation include UV (especially far UV), X, gamma rays and ionized particle from the Stellar Wind. If toxic radiation is over 100 times higher then on Earth, Earth-like life is seriously threatened and atmosphere becomes too ionized and might be blown into space.

Further parameters:

Extended habitable zone (for Sol 0.223 to 31.6 AU): After applying all these constrains, one can determine the extended Habitable Zone, where greenhouse gasses or anti-greenhouse technology can bring temperature within acceptable boundaries, plants have enough red and blue light and toxic UV radiation is within acceptable limits.
Earth-like planet orbit: The distance of a Habitable Zone Planet or Earth-Like Planet (for Sol, 1 AU) is where a planet can exist without greenhouse gasses or anti greenhouse technology. It is listed if it fits within the extended habitable zone.
Tidal index: The star's tidal force on a planet in the extended habitable zone.
Orbital period: the orbital period of a star within the extended habitable zone.
Angular Size: the size of the star as viewed from a planet in the habitable zone (Sol from Earth: 9.34). To see yourself how large a star would be as seen from a planet, draw a circle with the listed size in millimetres and look at it from a distance of one metre.

F0 Star[]

Main parameters:

Temperature: 7220
Mass: 1.61
Radius: 1.728
Bolometric magnitude: 2.58
Visual magnitude: 2.57

Spectral parameters:

Main light spectra: 440 (yellow-blue)

Solar constant: 5.83
Infrared light: 4.01
Red light: 5.30
Visible light: 6.06
Blue light: 7.51
Ultraviolet light: 39.8
Far UV light: 1259000

Habitable zone, based on light emissions:

Solar constant = 20: 0.540 AU
Solar constant = 1: 2.41 AU
Solar constant = 1/1000: 76.3 AU
Minimum red light: 72.8 AU
Minimum blue light: 86.7 AU
Maximum near UV light: 0.631 AU
Maximum far UV light: 0.001122 AU
Roche limit: 0.00014 AU

Further parameters:

Extended habitable zone: 0.631 - 72.8 AU
Earth-like planet orbit: 2.41 AU
Tidal index: 0.000304 - 4.04
Tidal index for Earth-like planet: 0.276
Orbit period (days): 144 - 178800 (490 years)
Orbital period for Earth-like planet: 1079 (3.0 years)
Angular size: 0.22 to 25.6
Angular size for Earth-like planet: 6.69.

F0 stars offer a large extended habitable zone, with both inner and outer possible planets suitable for terraforming.

F1 Star[]

Main parameters:

Temperature: 7020
Mass: 1.50
Radius: 1.679
Bolometric magnitude: 2.77
Visual magnitude: 2.76

Spectral parameters:

Main light spectra: 452 (yellow-blue)

Solar constant: 5.06
Infrared light: 3.65
Red light: 4.68
Visible light: 5.27
Blue light: 6.38
Ultraviolet light: 28.0
Far UV light: 271000

Habitable zone, based on light emissions:

Solar constant = 20: 0.503 AU
Solar constant = 1: 2.25 AU
Solar constant = 1/1000: 71.1 AU
Minimum red light: 68.4 AU
Minimum blue light: 79.9 AU
Maximum near UV light: 0.529 AU
Maximum far UV light: 0.000521 AU
Roche limit: 0.00014 AU

Further parameters:

Extended habitable zone: 0.529 - 68.4 AU
Earth-like planet orbit: 2.25 AU
Tidal index: 0.000320 - 5.36
Tidal index for Earth-like planet: 0.297
Orbit period (days): 114.7 - 168700 (462 years)
Orbital period for Earth-like planet: 1005 (2.8 years)
Angular size: 0.23 to 30.0
Angular size for Earth-like planet: 6.98.

F1 stars offer a large extended habitable zone, with both inner and outer possible planets suitable for terraforming.

F2 Star[]

Main parameters:

Temperature: 7020
Mass: 1.46
Radius: 1.622
Bolometric magnitude: 2.97
Visual magnitude: 2.97

Spectral parameters:

Main light spectra: 465 (yellow-blue)

Solar constant: 4.33
Infrared light: 3.28
Red light: 4.07
Visible light: 4.51
Blue light: 5.32
Ultraviolet light: 19.09
Far UV light: 52800

Habitable zone, based on light emissions:

Solar constant = 20: 0.465 AU
Solar constant = 1: 2.08 AU
Solar constant = 1/1000: 65.8 AU
Minimum red light: 63.8 AU
Minimum blue light: 72.9 AU
Maximum near UV light: 0.437 AU
Maximum far UV light: 0.000230 AU
Roche limit: 0.00014 AU

Further parameters:

Extended habitable zone: 0.465 - 63.8 AU
Earth-like planet orbit: 2.08 AU
Tidal index: 0.000359 - 6.75
Tidal index for Earth-like planet: 0.337
Orbit period (days): 95.8 - 153900 (421 years)
Orbital period for Earth-like planet: 906 (2.5 years)
Angular size: 0.24 to 32.6
Angular size for Earth-like planet: 7.29.

F2 stars offer a large extended habitable zone, with both inner and outer possible planets suitable for terraforming.

F3 Star[]

Main parameters:

Temperature: 6750
Mass: 1.44
Radius: 1.578
Bolometric magnitude: 3.07
Visual magnitude: 3.08

Spectral parameters:

Main light spectra: 470 (yellow-blue)

Solar constant: 3.97
Infrared light: 3.06
Red light: 3.76
Visible light: 4.14
Blue light: 4.83
Ultraviolet light: 16.12
Far UV light: 28300

Habitable zone, based on light emissions:

Solar constant = 20: 0.446 AU
Solar constant = 1: 1.992 AU
Solar constant = 1/1000: 63.0 AU
Minimum red light: 61.3 AU
Minimum blue light: 69.5 AU
Maximum near UV light: 0.401 AU
Maximum far UV light: 0.0001682 AU
Roche limit: 0.00014 AU

Further parameters:

Extended habitable zone: 0.446 - 61.3 AU
Earth-like planet orbit: 1.992 AU
Tidal index: 0.000383 - 7.25
Tidal index for Earth-like planet: 0.362
Orbit period (days): 90.5 - 145900 (399 years)
Orbital period for Earth-like planet: 855 (2.3 years)
Angular size: 0.24 to 33.1
Angular size for Earth-like planet: 7.40.

F3 stars offer a large extended habitable zone, with both inner and outer possible planets suitable for terraforming.

F4 Star[]

Main parameters:

Temperature: 6670
Mass: 1.38
Radius: 1.533
Bolometric magnitude: 3.19
Visual magnitude: 3.20

Spectral parameters:

Main light spectra: 476 (yellow-blue)

Solar constant: 3.62
Infrared light: 2.85
Red light: 3.44
Visible light: 3.77
Blue light: 4.35
Ultraviolet light: 13.32
Far UV light: 13720

Habitable zone, based on light emissions:

Solar constant = 20: 0.425 AU
Solar constant = 1: 1.901 AU
Solar constant = 1/1000: 60.1 AU
Minimum red light: 58.6 AU
Minimum blue light: 66.0 AU
Maximum near UV light: 0.365 AU
Maximum far UV light: 0.0001171 AU
Roche limit: 0.00013 AU

Further parameters:

Extended habitable zone: 0.425 - 58.6 AU
Earth-like planet orbit: 1.901 AU
Tidal index: 0.000401 - 7.63
Tidal index for Earth-like planet: 0.382
Orbit period (days): 86.1 - 139600 (382 years)
Orbital period for Earth-like planet: 815 (2.2 years)
Angular size: 0.24 to 33.7
Angular size for Earth-like planet: 7.53.

F4 stars are rather similar to the Sun, twice as bright and offering many possible orbits for hosted planets.

F5 Star[]

Main parameters:

Temperature: 6550
Mass: 1.33
Radius: 1.473
Bolometric magnitude: 3.35
Visual magnitude: 3.37

Spectral parameters:

Main light spectra: 485 (yellow)

Solar constant: 3.16
Infrared light: 2.57
Red light: 3.03
Visible light: 3.29
Blue light: 3.73
Ultraviolet light: 10.01
Far UV light: 4530

Habitable zone, based on light emissions:

Solar constant = 20: 0.398 AU
Solar constant = 1: 1.778 AU
Solar constant = 1/1000: 56.2 AU
Minimum red light: 55.1 AU
Minimum blue light: 61.1 AU
Maximum near UV light: 0.316 AU
Maximum far UV light: 0.0000673 AU
Roche limit: 0.00013 AU

Further parameters:

Extended habitable zone: 0.398 - 55.1 AU
Earth-like planet orbit: 1.778 AU
Tidal index: 0.000438 - 8.42
Tidal index for Earth-like planet: 0.421
Orbit period (days): 79.3 - 129400 (354 years)
Orbital period for Earth-like planet: 750 (2.1 years)
Angular size: 0.25 to 34.6
Angular size for Earth-like planet: 7.74.

F5 stars are rather similar to the Sun, twice as bright and offering many possible orbits for hosted planets.

F6 Star[]

Main parameters:

Temperature: 6350
Mass: 1.25
Radius: 1.359
Bolometric magnitude: 3.66
Visual magnitude: 3.69

Spectral parameters:

Main light spectra: 500 (yellow)

Solar constant: 2.45
Infrared light: 2.10
Red light: 2.38
Visible light: 2.53
Blue light: 2.80
Ultraviolet light: 5.94
Far UV light: 636

Habitable zone, based on light emissions:

Solar constant = 20: 0.350 AU
Solar constant = 1: 1.566 AU
Solar constant = 1/1000: 49.5 AU
Minimum red light: 48.8 AU
Minimum blue light: 52.9 AU
Maximum near UV light: 0.244 AU
Maximum far UV light: 0.0000252 AU
Roche limit: 0.00013 AU

Further parameters:

Extended habitable zone: 0.350 - 48.8 AU
Earth-like planet orbit: 1.566 AU
Tidal index: 0.000524 - 10.20
Tidal index for Earth-like planet: 0.510
Orbit period (days): 67.6 - 111400 (305 years)
Orbital period for Earth-like planet: 640 (1.8 years)
Angular size: 0.26 to 36.3
Angular size for Earth-like planet: 8.11.

F6 stars are rather similar to the Sun, twice as bright, with twice longer orbiting times and half tidal stress from the host star. Compared to visible light, near UV radiation is nearly 4 times stronger. Starting with F6 stars, near and far UV radiations are no longer a constraint for the habitable zone. UV radiation reaches deadly levels at 0.338 AU, but terraforming, using anti-greenhouse technology, is limited closer to 0.377 AU. Constraints imposed by UV light will not be shown for next stellar types.

F7 Star[]

Main parameters:

Temperature: 6280
Mass: 1.21
Radius: 1.324
Bolometric magnitude: 3.77
Visual magnitude: 3.8

Spectral parameters:

Main light spectra: 506 (yellow)

Solar constant: 2.25
Infrared light: 1.961
Red light: 2.20
Visible light: 2.32
Blue light: 2.53
Ultraviolet light: 4.94
Far UV light: 312.6

Habitable zone, based on light emissions:

Solar constant = 20: 0.335 AU
Solar constant = 1: 1.500 AU
Solar constant = 1/1000: 47.4 AU
Minimum red light: 46.9 AU
Minimum blue light: 50.3 AU
Roche limit: 0.00012 AU

Further parameters:

Extended habitable zone: 0.335 - 46.9 AU
Earth-like planet orbit: 1.500 AU
Tidal index: 0.000552 - 10.75
Tidal index for Earth-like planet: 0.538
Orbit period (days): 64.5 - 106500 (292 years)
Orbital period for Earth-like planet: 610 (1.7 years)
Angular size: 0.26 to 36.9
Angular size for Earth-like planet: 8.25.

F7 stars are rather similar to the Sun, twice as bright, with twice longer orbiting times and half tidal stress from the host star. Compared to visible light, near UV radiation is nearly 4 times stronger. Starting with F6 stars, near and far UV radiations are no longer a constraint for the habitable zone.

F8 Star[]

Main parameters:

Temperature: 6180
Mass: 1.18
Radius: 1.221
Bolometric magnitude: 4.01
Visual magnitude: 4.05

Spectral parameters:

Main light spectra: 514 (yellow)

Solar constant: 1.824
Infrared light: 1.632
Red light: 1.791
Visible light: 1.872
Blue light: 2.01
Ultraviolet light: 3.47
Far UV light: 101.3

Habitable zone, based on light emissions:

Solar constant = 20: 0.302 AU
Solar constant = 1: 1.351 AU
Solar constant = 1/1000: 42.7 AU
Minimum red light: 42.3 AU
Minimum blue light: 44.8 AU
Roche limit: 0.00012 AU

Further parameters:

Extended habitable zone: 0.302 - 42.3 AU
Earth-like planet orbit: 1.351 AU
Tidal index: 0.000659 - 12.94
Tidal index for Earth-like planet: 0.647
Orbit period (days): 55.8 - 92500 (253 years)
Orbital period for Earth-like planet: 527 (1.4 years)
Angular size: 0.27 to 37.8
Angular size for Earth-like planet: 8.45.

F8 stars are brighter, but similar to the Sun, slightly bluer. They offer good conditions for terraforming.

F9 Star[]

Main parameters:

Temperature: 6050
Mass: 1.13
Radius: 1.167
Bolometric magnitude: 4.2
Visual magnitude: 4.25

Spectral parameters:

Main light spectra: 525 (yellow)

Solar constant: 1.563
Infrared light: 1.449
Red light: 1.546
Visible light: 1.594
Blue light: 1.674
Ultraviolet light: 2.44
Far UV light: 25.1

Habitable zone, based on light emissions:

Solar constant = 20: 0.280 AU
Solar constant = 1: 1.250 AU
Solar constant = 1/1000: 39.5 AU
Minimum red light: 39.3 AU
Minimum blue light: 40.9 AU
Roche limit: 0.00012 AU

Further parameters:

Extended habitable zone: 0.280 - 39.3 AU
Earth-like planet orbit: 1.25 AU
Tidal index: 0.000731 - 14.46
Tidal index for Earth-like planet: 0.723
Orbit period (days): 50.8 - 84600 (231 years)
Orbital period for Earth-like planet: 480 (1.3 years)
Angular size: 0.28 to 39.0
Angular size for Earth-like planet: 8.72.

F9 stars are brighter, but similar to the Sun, slightly bluer. They offer good conditions for terraforming.

Conclusion[]

F - type stars are rather similar to the Sun, offering large habitable zones. Brighter stars (F0 to F5) have some constraints to their habitable zones, caused by their UV radiation and lack of red light. However, dimmer stars (F6 to F9) behave more similar to the Sun.

Main Sequence F Type Stars - Habitable Simulation

Contents

About the values[]

F0 Star[]

F1 Star[]

F2 Star[]

F3 Star[]

F4 Star[]

F5 Star[]

F6 Star[]

F7 Star[]

F8 Star[]

F9 Star[]

Conclusion[]

See Also[]