World Builders™                                                                                                              Session One  --  Astronomy      

                      
          Star Tables with More Detailed Information    

 

These are the most detailed star tables on this site.

 Star Tables

    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!

A simplified set of star tables may be found 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 live 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.

Bolometric Absolute Magnitude:

Stellar magnitude over all wavelengths as seen from ten Parsecs 32.6 Light years).  At that distance, the sun would appear to be a 4th magnitude star (4.75 to be precise).

Stars are different sizes, and some are much brighter than others. Astronomers classify stars by brightness. This is difficult because some stars are relatively close to us, while others are very far away. This measurement tells us how bright the different stars are when viewed from the same distance (but not the same place).

Bolometric Luminosity: a star's power output over all wavelengths (Sol = 1)

This includes light, heat, ultraviolet radiation, infrared radiation, gamma rays, and so on. Many wavelengths of the energy that stars radiate cannot be detected by our senses, but only with special instruments.

Bolometric Luminosity is the total energy put out by a star spread over all wavelengths. Use it for calculating the total energy balance and average effective temperature for a planet.

This is probably best for photosynthesis as well, however, for planets with deep atmospheres around very red stars, one might want to research atmospheric absorption as a function of wavelength and see how that compares to the stars blackbody spectrum. For planets with thick atmospheres or enhanced ozone layers around stars hotter than the sun, use visual luminosity for photosynthesis, as atmospheres attenuate ultraviolet light much more than visual.

L Zams:

Zero Age luminosity; bolometric luminosity after the star's
initial contraction; this is problematical for late M stars
and below, which contract essentially forever.

Visual Luminosity:

in terms of Sol at the same distance. For hotter or cooler stars this is less than L bol, because much of those star's radiation is in the invisible ultraviolet (very hot) or infrared (warm) part of the spectrum. If one was close enough 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. The radius is the distance from the center of the star to its outer boundary.

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,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, as 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

 Bolometric Absolute Magnitude

Bolometric Luminosity   L Zams  Visual Luminosity  Mass
(Mass of our sun = 1)
 Radius Terrestrial Equivalent Orbit
in AUs
Lifetime
in billions of years
                   
 04  48000  -10.24  990000.00  980000.00  1.75E4  90.000  14.400  995.00  .002
 05  44500  -9.99  790000.00  560000.00  1.46E4  60.000  15.000  889.00  .004
 06  41000  -9.31  420000.00  238000.00  1.20E4  37.000  12.900  648.00  .005
 07  38000  -8.79  260000.00  140000.00  9350.00  30.000  11.800  510.00  .006
 08  35800  -8.33  170000.00  84500.00  6960.00  23.000  10.800  412.00  .008
 09  33000  -7.72  97000.00  62700.00  4820.00  23.300  9.560  311.00  .009

B Class Stars -- Hot and Fast Burning

 Class  Temp/K  Bolometric Absolute Magnitude Bolometric Luminosity   L Zams  Visual Luminosity  Mass (Mass of our sun = 1)  Radius  Terrestrial Equivalent Orbit
in AUs
Lifetime in billions of years
                   
B0 30000 -7.04 52000.00 40800.00 3020.00 17.500 8.470 228.00  .010
B1 25400 -5.76 16000.00 18800.00 1420.00 14.200 6.560 126.00  .013
B2 22000 -4.64 5700.00 9720.00 698.00 10.900 5.220 75.50  .020
B3 18700 -3.45 1900.00 3150.00 339.00 7.600 4.170 43.60  .043
B5 15400 -2.55 830.00 1500.00 231.00 5.900 4.060 28.80  .066
B6 14000 -2.00 500.00 823.00 175.00 5.200 3.810 22.40  .075
 B7 13000   -1.51  320.00  496.00  133.00  4.500  3.540  17.90  .198
 B8  11900  -.89  180.00  308.00  91.90  3.800  3.170  13.40  .367
 B9  10500  -.19  95.00  187.00  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  Bolometric Absolute Magnitude Bolometric Luminosity   L Zams  Visual Luminosity  Mass (Mass of our sun = 1)  Radius Terrestrial Equivalent Orbit
in AUs
Lifetime in billions of years
                   
A0 9520 .42 54.00 87.20 43.70 2.900 2.710 7.35  .583
A1 9230 .89 35.00 76.60 30.20 2.720 2.320 5.92  .627
A2 8970 1.21 26.00 66.10 23.10 2.540 2.120 5.10  .670
A3 8720 1.44 21.00 55.60 19.20 2.360 2.010 4.58  .713
A5 8200 1.88 14.00 34.60 13.00 2.000 1.860 3.74  .800
A7 7850 2.20 10.50 25.30 10.00 1.840 1.760 3.24 1.120 
 A8  7580  2.41  8.60  20.60  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  Bolometric Absolute Magnitude Bolometric Luminosity   L Zams  Visual Luminosity  Mass (Mass of our sun = 1)  Radius Terrestrial Equivalent Orbit
in AUs
Lifetime in billions of years
                   
F0  7200  2.72 6.50  11.20  6.38 1.600  1.640  2.55  1.600
F2 6890 3.17 4.30 6.57 4.14 1.520 1.460 2.07  1.760
F5 6440 3.49 3.20 4.47 3.00 1.400 1.440 1.79  3.440
F8 6200 3.94 2.10 2.51 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  Bolometric Absolute Magnitude Bolometric Luminosity   L Zams  Visual Luminosity  Mass (Mass of our sun = 1)  Radius Terrestrial Equivalent Orbit
in AUs
Lifetime
in billions of years
                   
G0 6030 4.31 1.50 1.21 1.36 1.050 1.130 1.22  9.180
G2 5860 4.65 1.10 .74 .97 .998 1.020 1.05 10.100
G5 5770 5.01 .79 .63 .69 .920 .893 .89  14.000
G8 5570 5.20 .66 .51 .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  Bolometric Absolute Magnitude Bolometric Luminosity   L Zams  Visual Luminosity  Mass (Mass of our sun = 1)  Radius Terrestrial Equivalent Orbit
in AUs
Lifetime in billions of years
                   
K0 5250 5.69 .42 .45 .34 .790 .786 .65  21.100
K1 5080 5.83 .37 .41 .28 .766 .788 .61  long
K2 4900 6,09 .29 .38 .21 .742 .750 .54  
K3 4730 6.21 .26 .34 .18 .718 .762 .51  
K4 4590 6.55 .19 .31 .12 .694 .692 .43  very
K5 4350 6.81 .15 .27 82.4E-3 .670 .684 .39  long
 K7  4060  7.25  .10 .19  42.1E-3 .606  .641 .32  

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

 Class  Temperature in degrees Kelvin  Bolometric Absolute Magnitude Bolometric Luminosity   L Zams  Visual Luminosity  Mass (Mass of our sun = 1)  Radius Terrestrial Equivalent Orbit
in AUs
                 
M0 3850 7.53 77.00E-3 52.00E-3 23.0E-3 .510 .626 .28
M1 3720 7.79 61.00E-3 38.80E-3 14.6E-3 .445 .597 .25
M2 3580 8.12 45.00E-3 27.70E-3 8.42E-3 .400 .553 .21
M3 3470 8.36 36.00E-3 24.00E-3 5.30E-3 .350 .527 .19
M4 3370 9.05 19.00E-3 19.40E-3 2.26E-3 .300 .406 .13
M5 3240 9.65 11.00E-3 14.70E-3 .95E-3 .250 .334 .11
 M6 3050 10.44  5.30E-3 10.70E-3 .29E-3 .207 .262 72.8E-3
 M7 2940 10.92  3.40E-3  7.06E-3 .15E-3 .163 .226 58.3E-3
 M8 2640  12.05  1.20E-3  2.67E-3 29.30E-6  .120 .166 35.0E-3 
 M9 2510 13.56  0.30E-3  .30E-3  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  Bolometric Absolute Magnitude Bolometric Luminosity   L Zams  Visual Luminosity  Mass (Mass of our sun = 1)  Radius Terrestrial Equivalent Orbit
in AUs
                 
E0 1800 15.74 40.00E-6 NA 277.0E-9 .080 .065 6.3E-3
E2 1600 16.06 30.00E-6 NA 4.2E-9 .072 .072 5.5E-3
E4 1300 16.74 16.O0E-6 NA 1.0E-9 .064 .079 4.0E-3
E6 1000 17.25 10.00E-6 NA -- .053 .106 3.7E-3
E8 800 18.00 5.00E-6 NA 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  Bolometric Absolute Magnitude Bolometric Luminosity   L Zams  Visual Luminosity  Mass (Compared to mass of Jupiter (.001 of our sun))  Radius Terrestrial Equivalent Orbit
in AUs
                 
J0 700 18.56 3.00E-6 NA dim MJ .118 .118 1.7E-3
J2 600 19.31 1.50E-6 NA to MJ .114 .114 1.2E-3
J4 400 21.06 .30E-6 NA see MJ .114 .114 .5E-3
J7 100 27.25 1.00E-9 NA with MJ .106 .106 Below
J8 80 29.11 .18E-9 NA human MJ .070 .070 surface
J9 50 32.56 7.50E-12 NA eyes MJ .037 .037 Below
 Non-
Luminous
 30  34.75  1.00E-12  NA  --  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.