See p. 210, table 32.\n"""
if not isinstance(when, find):
when = find(None, when)
# pity about not knowing eccentricities ...
return rock(name,
sol.orbiter(Q(period, 2, None, yr)),
Q(1, 2, 12, mass * ton),
maxdiameter=Q(maxdiam, 0, None, ml),
periterrion=Q(1, 2, 6, miss * ml), # closest approach to Terra
discovery=when)
Ceres = DwarfAster('Ceres',
Orbit(Sun, Quantity.fromDecimal(413.9, 1, 6, km), None),
Quantity.fromDecimal(.87, 2, 21, kg),
surface = Spheroid(Quantity.fromDecimal(466, 0, None, km)),
number = 1,
discovery=Discovery("Piazzi", 1801,
day="January 1st 1801",
__doc__="""The discovery of Ceres.
A team of astronomers set out, in 1800, to look for a planet between Mars and
Jupiter, as anticipated by the Titius-Bode law (see Sun.Bode); starting on the
first day of the new year, Piazzi noticed a moving star which was, in due
course, recognised as what they were looking for, even though it was a bit
smaller than they expected and a few more showed up soon enough.\n"""),
__doc__="""The first asteroid discovered.
See Ceres.discovery and Sun.Bode for further details. Piazzi actually named
Most of our uncertainty about this arises from our ignorance of our motion
relative to the Local Group: we know our own velocity relative to the background
radiation far more accurately.
See also: http://antwrp.gsfc.nasa.gov/apod/ap030209.html
""",
l = Quantity.within(273, 3, arc.degree),
b = Quantity.within(30, 3, arc.degree)),
mass = Quantity.fromDecimal(
2, 0, 43, kg,
"""Estimated mass of the Local Group
The mass inwards from radius R within each galaxy grows in proportion to R,
which might suggest that galactic masses vary in proportion to radii; a simple
uniform area density model in each galactic disk would predict masses
proportional to squares of radii; and a simple spherical model at fixed density
would use the cubes. When I summed R**P for radii R and power P, dividing the
total by the Milky Way's contribution, the ratio has a minimum of about 4.16 at
about P = 1.9, falling from just under 6 at P = 1 and rising to just over 5 at P
= 3 (however, these results are quite sensitive to variations in the value used
for the radius of the Milky Way, shifting significantly even between 90 and 100
M ly). It thus seems reasonable to estimate that the mass of the local group is
between four and six times that of the Milky Way.
"""))
# NB: MilkyWay.mass figure used is *not* the temporary one given immediately
# below; see later correction once Sun has been successfully added as a
# satelite.
MilkyWay = body.Galaxy('Milky Way', mass=1.79e41 * kg,
# NB: actual mass is O(1e42) - but see below !
orbit = Orbit(LocalGroup,
if not isinstance(when, find):
when = find(None, when)
# pity about not knowing eccentricities ...
return rock(
name,
sol.orbiter(Q(period, 2, None, yr)),
Q(1, 2, 12, mass * ton),
maxdiameter=Q(maxdiam, 0, None, ml),
periterrion=Q(1, 2, 6, miss * ml), # closest approach to Terra
discovery=when)
Ceres = DwarfAster('Ceres',
Orbit(Sun, Quantity.fromDecimal(413.9, 1, 6, km), None),
Quantity.fromDecimal(.87, 2, 21, kg),
surface=Spheroid(Quantity.fromDecimal(466, 0, None, km)),
number=1,
discovery=Discovery("Piazzi",
1801,
day="January 1st 1801",
__doc__="""The discovery of Ceres.
A team of astronomers set out, in 1800, to look for a planet between Mars and
Jupiter, as anticipated by the Titius-Bode law (see Sun.Bode); starting on the
first day of the new year, Piazzi noticed a moving star which was, in due
course, recognised as what they were looking for, even though it was a bit
smaller than they expected and a few more showed up soon enough.\n"""),
__doc__="""The first asteroid discovered.
def NASelement(name, symbol, Z, A, isos=None, abundance=None, melt=None, boil=None, **what):
"""Create an Element based on my Nuffield Advanced Data book's data.
Required arguments:
name -- string giving the full name of the element.
symbol -- string giving the (one or two letter) symbol of the element.
Z -- atomic number.
Optional arguments:
A -- molar mass * mol / g; a.k.a. atomic mass / AMU (default, None, means
unknown).
isos -- description of isotopes (see below); default is None.
abundance -- relative terrestrial abundance, scaled to make Si score 100;
default is None, indicating an artificial element.
melt -- melting temperature / K
boil -- boiling temperature / K
plus any further keyword arguments, to taste. See Element's constructor for
further details; it receives a suitably scaled abundance.
I have, rather arbitrarily, supposed that the phase change temperatures
given in the NAS data book generally have an error bar of +/- half a Kelvin,
except where marked as 'uncertain' (five K) or 'highly uncertain' (fifty K
if the cited value's last two digits are zeros, otherwise ten K). Roughly
as arbitrarily, where several forms of the elment are listed, I've used the
lowest melting point and highest boiling point, ignoring any phase changes
between forms and listing any sublimation (typically relevant only to one
form, not the one whose melting and boiling are used) separately as sublime.
The description of isotopes, if given, should either be a list of atomic
mass numbers for which an isotope is known (for artificial elements and
those natural radioactives whose isotopic composition varies wildly) or a
mapping from known atomic mass numbers to relative abundances (or to None
for those radioactive isotopes which normally have negligible abundance).
If the sum of these relative abundances isn't 1, they'll be (fudged to make
it 100 - because the NAS book is a bit off on some elements - and then)
scaled down to make it 1.
Both the element's terrestrial abundance and the relative abundance of its
isotopes will be given an error bar, if they don't already have one, to
accord with the limited precision indicated in the NAS table. """
if abundance is None:
what["abundance"] = None # artificial elements
else:
try:
abundance.width
except AttributeError: # need an error bar (guess: two decimal places of precision)
abundance = Quantity.fromSigFigs(abundance, 2)
# NAS data book gives abundances relative to Silicon = 100, but notes
# that Silicon's true abundance is believed to be 27.72 %
what["abundance"] = abundance * 0.2772
try:
A.width
except AttributeError: # give it an error bar
try:
isos[:] # radioactive/artificial elements
except TypeError:
A = Quantity.fromDecimal(A, 4) # real ones
else:
A = Quantity.within(A, 0.5 * max(1, max(isos) - min(isos)))
temp = {}
if melt is not None:
try:
melt.width
except AttributeError:
melt = Quantity.fromDecimal(melt, 1)
temp["melt"] = melt * Kelvin
if boil is not None:
try:
boil.width
except AttributeError:
boil = Quantity.fromDecimal(boil, 1)
temp["boil"] = boil * Kelvin
try:
temp["sublime"] = what["sublime"]
except KeyError:
pass
else:
del what["sublime"]
if temp:
T = Temperatures(**temp)
else:
T = None
ans = Element(name, symbol, Z, A, T, **what)
try:
isos[:]
except TypeError:
try:
isos.update
except AttributeError:
pass # no information
else:
# dictionary: { isotope: relative abundance }
weights = filter(None, isos.values())
total = sum(weights)
if total == 1:
fix, scale = None, 1 # weights given as fractions
else:
# Otherwise, assume given as percentages; but the NAS table
# has several entries that don't sum accurately to 100.
scale = 0.01
if total == 100:
fix = None
else: # bodge: blur the non-tiny weights to make it all sum right ...
assert 80 < total < 120, "Perhaps these aren't percentages after all"
fix = 1 + (100 - total) * Quantity.below(2) / sum(filter(lambda x: x > 1, weights))
# Perhaps we can improve on this ...
for k, v in isos.items():
iso = Isotope(Z, k - Z)
if v:
unit = 1
if v < 1:
while unit > v:
unit = unit * 0.1
unit = unit * 0.1
if fix and v > 1:
v = v * fix # bodge
v = Quantity.within(v, unit * 0.01)
iso.abundance = v * scale
else:
# sequence: known isotopes
for k in isos:
Isotope(Z, k - Z)
return ans
Iron = NASelement(
"Iron", "Fe", 26, Float(55.847, 3), {54: 5.84, 56: 91.68, 57: 2.17, 58: 0.31}, 22, 1812, 3160, arcanum="Ferrum"
)
Cobalt = NASelement("Cobalt", "Co", 27, 58.9332, {59: 1}, 0.01, 1768, 3150)
Nickel = NASelement("Nickel", "Ni", 28, 58.71, {58: 67.76, 60: 26.16, 61: 1.25, 62: 3.66, 64: 1.16}, 3.5e-2, 1728, 3110)
Copper = NASelement(
"Copper",
"Cu",
29,
Float(63.54, 3),
{63: 69.1, 65: 30.9},
3.1e-2,
1356,
2855,
arcanum="Cuprum",
resistivity=Quantity.fromDecimal(16.8, 1) * nano * Ohm * metre,
)
# resistivity: http://www.irregularwebcomic.net/3295.html
Zinc = NASelement("Zinc", "Zn", 30, 65.37, {64: 48.89, 66: 27.81, 67: 4.11, 68: 18.56, 70: 0.62}, 5.8e-2, 693, 1181)
Gallium = NASelement("Gallium", "Ga", 31, 69.72, {69: 60.2, 71: 39.8}, 6.6e-3, 303, Float(2510, -1))
Germanium = NASelement(
"Germanium", "Ge", 32, 72.59, {70: 20.55, 72: 27.37, 73: 7.67, 74: 36.74, 76: 7.67}, 3.1e-3, 1210, Float(3100, -2)
)
Arsenic = NASelement("Arsenic", "As", 33, 74.9216, {75: 1}, 2.2e-3, sublime=Float(886, 1, None, Kelvin))
Selenium = NASelement(
"Selenium", "Se", 34, 78.96, {74: 0.89, 76: 9.02, 77: 7.58, 78: 23.52, 80: 49.82, 82: 9.19}, 4e-5, 490, 958
)
Bromine = NASelement("Bromine", "Br", 35, About(79.909, 0.001), {79: 50.52, 81: 49.48}, 7.1e-4, 266, 331)
Krypton = NASelement(
"Krypton", "Kr", 36, 83.8, {78: 0.35, 80: 2.27, 82: 11.56, 83: 11.55, 84: 56.9, 86: 17.37}, 4.3e-8, 116, 120
)
Most of our uncertainty about this arises from our ignorance of our motion
relative to the Local Group: we know our own velocity relative to the background
radiation far more accurately.
See also: http://antwrp.gsfc.nasa.gov/apod/ap030209.html
""",
l = Quantity.within(273, 3, arc.degree),
b = Quantity.within(30, 3, arc.degree)),
mass = Quantity.fromDecimal(
2, 0, 43, kg,
"""Estimated mass of the Local Group
The mass inwards from radius R within each galaxy grows in proportion to R,
which might suggest that galactic masses vary in proportion to radii; a simple
uniform area density model in each galactic disk would predict masses
proportional to squares of radii; and a simple spherical model at fixed density
would use the cubes. When I summed R**P for radii R and power P, dividing the
total by the Milky Way's contribution, the ratio has a minimum of about 4.16 at
about P = 1.9, falling from just under 6 at P = 1 and rising to just over 5 at P
= 3 (however, these results are quite sensitive to variations in the value used
for the radius of the Milky Way, shifting significantly even between 90 and 100
M ly). It thus seems reasonable to estimate that the mass of the local group is
between four and six times that of the Milky Way.
"""))
# NB: MilkyWay.mass figure used is *not* the temporary one given immediately
# below; see later correction once Sun has been successfully added as a
# satelite.
MilkyWay = body.Galaxy('Milky Way', mass=1.79e41 * kg,
# NB: actual mass is O(1e42) - but see below !
orbit = Orbit(LocalGroup,
Phosphorus = NASelement('Phosphorus', 'P', 15, 30.9738, {31: 1}, 5.2, 317, 554, sublime=704*Kelvin)
Sulphur = NASelement('Sulphur', 'S', 16, About(32.064, 1.5e-3), {32: 95, 33: .76, 34: 4.22, 36: .01}, .23, Float(392, -1), 718, alias=('Sulfur',))
Chlorine = NASelement('Chlorine', 'Cl', 17, Float(35.453, 3), {35: 75.53, 37: 24.47}, .14, 172, 239)
Argon = NASelement('Argon', 'Ar', 18, 39.9480, {36: .34, 38: .063, 40: 99.6}, 1.8e-5, 84, 87, alias=('A',))
Potassium = NASelement('Potassium', 'K', 19, 39.102, {39: 93.22, 40: .12, 41: 6.77}, # components sum to 100.11, not 100
11.4, 336, 1039, arcanum='Kalium')
Calcium = NASelement('Calcium', 'Ca', 20, 40.08, {40: 96.97, 42: .64, 43: .15, 44: 2.06, 46: .003, 48: .19}, 16, 1123, 1765)
Scandium = NASelement('Scandium', 'Sc', 21, 44.956, {45: 1}, 2.2e-3, About(1673, 10), About(2750, 10))
Titanium = NASelement('Titanium', 'Ti', 22, 47.9, {46: 7.99, 47: 7.32, 48: 73.99, 49: 5.46, 50: 5.25}, 1.4, 1950, 3550)
Vanadium = NASelement('Vanadium', 'V', 23, 50.942, {50: .25, 51: 99.75}, 6.6e-2, 2190, 3650)
Chromium = NASelement('Chromium', 'Cr', 24, Float(51.996, 3), {50: 4.31, 52: 83.76, 53: 9.55, 54: 2.38}, 4.4e-2, 2176, 2915)
Manganese = NASelement('Manganese', 'Mn', 25, 54.938, {55: 1}, .44, 1517, 2314)
Iron = NASelement('Iron', 'Fe', 26, Float(55.847, 3), {54: 5.84, 56: 91.68, 57: 2.17, 58: .31}, 22, 1812, 3160, arcanum='Ferrum')
Cobalt = NASelement('Cobalt', 'Co', 27, 58.9332, {59: 1}, .01, 1768, 3150)
Nickel = NASelement('Nickel', 'Ni', 28, 58.71, {58: 67.76, 60: 26.16, 61: 1.25, 62: 3.66, 64: 1.16}, 3.5e-2, 1728, 3110)
Copper = NASelement('Copper', 'Cu', 29, Float(63.54, 3), {63: 69.1, 65: 30.9}, 3.1e-2, 1356, 2855, arcanum='Cuprum', resistivity=Quantity.fromDecimal(16.8, 1) * nano * Ohm * metre)
# resistivity: http://www.irregularwebcomic.net/3295.html
Zinc = NASelement('Zinc', 'Zn', 30, 65.37, {64: 48.89, 66: 27.81, 67: 4.11, 68: 18.56, 70: .62}, 5.8e-2, 693, 1181)
Gallium = NASelement('Gallium', 'Ga', 31, 69.72, {69: 60.2, 71: 39.8}, 6.6e-3, 303, Float(2510, -1))
Germanium = NASelement('Germanium', 'Ge', 32, 72.59, {70: 20.55, 72: 27.37, 73: 7.67, 74: 36.74, 76: 7.67}, 3.1e-3, 1210, Float(3100, -2))
Arsenic = NASelement('Arsenic', 'As', 33, 74.9216, {75: 1}, 2.2e-3, sublime=Float(886, 1, None, Kelvin))
Selenium = NASelement('Selenium', 'Se', 34, 78.96, {74: .89, 76: 9.02, 77: 7.58, 78: 23.52, 80: 49.82, 82: 9.19}, 4e-5, 490, 958)
Bromine = NASelement('Bromine', 'Br', 35, About(79.909, .001), {79: 50.52, 81: 49.48}, 7.1e-4, 266, 331)
Krypton = NASelement('Krypton', 'Kr', 36, 83.8, {78: .35, 80: 2.27, 82: 11.56, 83: 11.55, 84: 56.9, 86: 17.37}, 4.3e-8, 116, 120)
Rubidium = NASelement('Rubidium', 'Rb', 37, 85.47, {85: 72.15, 87: 27.85}, .14, 312, 974)
Strontium = NASelement('Strontium', 'Sr', 38, 87.62, {84: .56, 86: 9.86, 87: 7.02, 88: 82.56}, .13, 1043, 1640)
Yttrium = NASelement('Yttrium', 'Y', 39, 88.905, {89: 1}, 1.2e-2, About(1773, 10), Float(3500, -2))
Zirconium = NASelement('Zirconium', 'Zr', 40, 91.22, {90: 51.46, 91: 11.23, 92: 17.11, 94: 17.4, 96: 2.8}, 9.7e-2, 2125, 4650)
Niobium = NASelement('Niobium', 'Nb', 41, 92.9060, {93: 1}, 1.1e-2, 2770, 5200, alias=('Columbium', 'Cb'))
Molybdenum = NASelement('Molybdenum', 'Mo', 42, 95.94, {92: 15.86, 94: 9.12, 95: 15.7, 96: 16.5, 97: 9.45, 98: 23.75, 100: 9.62}, 6.6e-3, Float(2890, -1), Float(5100, -1))
Technetium = NASelement('Technetium', 'Tc', 43, 99, [99], None, Float(2400, -2), Float(4900, -2))
