Star Tables

   

                                                                  Simplified, all classes represented

This third law will allow you to figure out how long your planet's year will be.

     These star tables and some of the comments were sent to us by Gerald Nordley, science fiction writer, member of the CONTACT group, and a very good friend to world builders! Thank you very much for your help, Mr Nordley!

This is a basic star table. More information is available here.

Notes on these star tables:

The stars in these tables are arranged in the classes used in the Main Sequence. Choose your star from these tables and you will have some of the numbers that you need for your solar system and your planet.

Our sun is a G2 star. As we found out from our hands-on activity, our sun formed 4.5 billion years ago. Earth also formed about 4.5 billion years ago, and 3.2 billion years ago, or perhaps even earlier, the first single celled life forms appeared. When you consider that the earth had to cool from a molten state first, life seems to have appeared quite quickly. However, the jump to multicellular life forms took a long time. Multicellular life forms began to develop only 600 million years. If you want to have life forms that you can actually see, you need to choose a star with a long enough life time.

You should choose your star type from these tables. Write down the information about that star's row, with the headings.

What the Headings mean:

Class: See the page on Main Sequence

Temperature in Degrees Kelvin:

See page on Temperatures in Space. The temperature given is the surface temperature of the star.

Visual Luminosity:

in terms of our sun, Sol, at the same distance. For hotter or cooler stars this is less than our sun, because much of those stars' radiation is in the invisible ultraviolet (very hot) or infrared (warm) part of the spectrum. If one so close to a red dwarf that it appeared as bright as the sun, one would get about 100 times less ultraviolet intensity.

Mass (Mass of our sun = 1): See page on Weight, Mass, and Density.

Radius:

Radii are estimated from temperature and luminosity, except for the planets at the bottom of this table. The radius is the distance from the center of the star to its surface.

Terrestrial Equivalent Orbit in AUs:

the distance to a star where one gets Earth's solar intensity (1372 W/m^2). For very dim stars, planets would have to be very close, and tidal effects are of concern.

This is important because it will help you to put your world in the Life Zone of your solar system.

Lifetime in Billions of Years:

This is how long your star will burn in a stable way. Remember, you need to allow time for your life forms to develop.

Important Math Note:

In numbers in the form of 1.23E-3, the E-3 stands for ten to the inverse third power, and is an instruction to divide by ten cubed (1000). (10 cubed means 10 x 10 x 10)

Thus E-3 means thousandths (1/1000)
E-6 means millionths (1/1,000,000) and
E-9 means (U.S.) billionths (1/1,000,000,000).

If you look at these tables you will see interesting changes as the stars get smaller. Pay special attention to the colored sections of the tables: you will be using these numbers in planning your own solar system.

O Class Stars -- Very Large, Very Hot, Very Fast Burning

 Class Temperature in degrees Kelvin  Visual Luminosity  Mass
(Mass of our sun = 1)

 Radius

(Radius of Sun=1)

Terrestrial Equivalent Orbit
in AUs
Lifetime
in billions of years
             
 04  48000  1.75E4  90.000  14.400  995.00  .002
 05  44500  1.46E4  60.000  15.000  889.00  .004
 06  41000  1.20E4  37.000  12.900  648.00  .005
 07  38000  9350.00  30.000  11.800  510.00  .006
 08  35800  6960.00  23.000  10.800  412.00  .008
 09  33000  4820.00  23.300  9.560  311.00  .009

B Class Stars -- Hot and Fast Burning

 Class  Temp/K  Visual Luminosity  Mass (Mass of our sun = 1)

Radius

(Radius of Sun=1)

 Terrestrial Equivalent Orbit
in AUs
Lifetime in billions of years
             
B0 30000 3020.00 17.500 8.470 228.00  .010
B1 25400 1420.00 14.200 6.560 126.00  .013
B2 22000 698.00 10.900 5.220 75.50  .020
B3 18700 339.00 7.600 4.170 43.60  .043
B5 15400 231.00 5.900 4.060 28.80  .066
B6 14000 175.00 5.200 3.810 22.40  .075
 B7 13000   133.00  4.500  3.540  17.90  .198
 B8  11900  91.90  3.800  3.170  13.40  .367
 B9  10500  63.30  3.350  2.960  9.75  .475

A Class Stars -- Do Not Last Long Enough to Support Complex Life Forms

 Class

 Temperature in degrees Kelvin

 Visual Luminosity  Mass (Mass of our sun = 1)

 Radius

(Radius of Sun=1)

Terrestrial Equivalent Orbit
in AUs
Lifetime in billions of years
             
A0 9520 43.70 2.900 2.710 7.35  .583
A1 9230 30.20 2.720 2.320 5.92  .627
A2 8970 23.10 2.540 2.120 5.10  .670
A3 8720 19.20 2.360 2.010 4.58  .713
A5 8200 13.00 2.000 1.860 3.74  .800
A7 7850 10.00 1.840 1.760 3.24 1.120 
 A8  7580  8.37  1.760  1.710  2.93  1.280

Class F Stars: Some of These Might Have Life-Bearing Planets

 Class  Temperature in degrees Kelvin  Visual Luminosity  Mass (Mass of our sun = 1)

Radius

(Radius of Sun=1)

Terrestrial Equivalent Orbit
in AUs
Lifetime in billions of years
             
F0  7200  6.38 1.600  1.640  2.55  1.600
F2 6890 4.14 1.520 1.460 2.07  1.760
F5 6440 3.00 1.400 1.440 1.79  3.440
F8 6200 1.93 1.190 1.260 1.45  6.880

G Class Stars: Possible Suns for Planets with Life: The Sun is a G2 Star

 Class  Temperature in degrees Kelvin  Visual Luminosity  Mass (Mass of our sun = 1)

 Radius

(Radius of Sun=1)

Terrestrial Equivalent Orbit
in AUs
Lifetime
in billions of years
             
G0 6030 1.36 1.050 1.130 1.22  9.180
G2 5860 .97 .998 1.020 1.05 10.100
G5 5770 .69 .920 .893 .89  14.000
G8 5570 .56 .842 .875 .81  17.900

K Class Stars: Small, Dim, Red Stars: Could Perhaps Support Life On Inner Planets

 Class  Temperature in degrees Kelvin  Visual Luminosity  Mass (Mass of our sun = 1)

 Radius

(Radius of Sun=1)

Terrestrial Equivalent Orbit
in AUs
Lifetime in billions of years
             
K0 5250 .34 .790 .786 .65  21.100
K1 5080 .28 .766 .788 .61  long
K2 4900 .21 .742 .750 .54  
K3 4730 .18 .718 .762 .51  
K4 4590 .12 .694 .692 .43  very
K5 4350 82.4E-3 .670 .684 .39  long
 K7  4060  42.1E-3 .606  .641 .32  

M Class Stars: Less than Half the Mass of Our Sun

 Class  Temperature in degrees Kelvin  Visual Luminosity  Mass (Mass of our sun = 1)

 Radius

(Radius of Sun=1)

Terrestrial Equivalent Orbit
in AUs
           
M0 3850 23.0E-3 .510 .626 .28
M1 3720 14.6E-3 .445 .597 .25
M2 3580 8.42E-3 .400 .553 .21
M3 3470 5.30E-3 .350 .527 .19
M4 3370 2.26E-3 .300 .406 .13
M5 3240 .95E-3 .250 .334 .11
 M6 3050 .29E-3 .207 .262 72.8E-3
 M7 2940 .15E-3 .163 .226 58.3E-3
 M8 2640  29.30E-6  .120 .166 35.0E-3 
 M9 2510  1.16E-6  .100 .092  17.0E-3

Below: The E0 Class contains the the lowest mass Main Sequence stars.
Stars less massive than class E0 are called Brown Dwarfs.

Small, Heat-Radiating Bodies Less Than a Tenth the Mass of Our Sun

 Class  Temperature in degrees Kelvin  Visual Luminosity  Mass (Mass of our sun = 1) Radius
(Radius of Sun=1)
Terrestrial Equivalent Orbit
in AUs
           
E0 1800 277.0E-9 .080 .065 6.3E-3
E2 1600 4.2E-9 .072 .072 5.5E-3
E4 1300 1.0E-9 .064 .079 4.0E-3
E6 1000 -- .053 .106 3.7E-3
E8 800 Too .040 .117 2.2E-3

Below: MJ means Jupiter masses, each about 1/1000 the mass of the sun.
The Brown Dwarf/Jovian Transition is between E8 and J0

Astronomical Bodies Smaller than Mass of Jupiter: Radiate Heat

 Class  Temperature in degrees Kelvin  Visual Luminosity  Mass (Compared to mass of Jupiter (.001 of our sun))

Radius

(Radius of Sun=1)

Terrestrial Equivalent Orbit
in AUs
           
J0 700 dim MJ .118 .118 1.7E-3
J2 600 to dim MJ .114 .114 1.2E-3
J4 400 to see MJ .114 .114 .5E-3
J7 100 with MJ .106 .106 Below
J8 80 human MJ .070 .070 surface
J9 50 eyes MJ .037 .037 Below
 Non-
Luminous
 30  --  MJ .037  .037  surface


The bottom end of the Jovian scale consists of Jupiter, Saturn Neptune and Uranus in that order, with effective temperatures from Lang, adjusted for solar heating and known radius values Jupiter is a J7.