Useful Data

Some maths...

1 deg2 = 4 sin2(PI/360) sr ~ (PI/360)2 sr (accuracy 10-5)
4 PI sr ~ 129600/PI deg2 ~ 41253 deg2
PI ~ 3.1415626535

Physical constants

Speed of light in vacumm c = 299 792 458 m/s
Planck constant h = 6.626 x 10-34 J s
Boltzmann constant kB = 1.380 x 10-23 J K-1
Gravitational constant G = 6.673(10) x 10-11 m3 kg-1 s-2

Astrophysical constants

Distances

Astronomical unit (mean earth-sun distance) au = 149 597 870 660(20) m
Parsec pc = 3.085 677 x 1016 m = 3.262 ly
Light-year ly = 9.461 x 1015 m

Sun

Solar mass Msun = 1.988 9(30) x 1030 kg
Solar equatorial radius Rsun = 6.961 x 108 m
Solar luminosity Lsun = (3.846 ± 0.008) x 1026 W
Effective temperature Tsun = 5770 K
Spectral type G2 V

Apparent magnitude Absolute magnitude
U = -26.06
B = -26.16
V = -26.78
mbol = -26.85
MU = +5.51
MB = +5.41
MV = +4.79
Mbol = +4.72

Earth

Earth mass Mearth = 5.974(9) x 1024 kg
Earth mean equatorial radius Rearth = 6.378 140 x 106 m

Milky Way

Type of galaxy Sb (-Sb+)I-II (Hubble - Van den Bergh system)
SAB(rs)bc II (de Vaucouleur's system)
Diameter 23 kpc (isophot(B) 25.0 mag/arsec)
Period of rotation 2.5 x 108 yr
Mass Total = 1.8 x 1011 Msun
Gas = 8 x 109 Msun
Sun speed around galactic center Thetao = 220(20) km/s
Solar distance from galactic center Ro = 8.0(5) kpc

Cosmology

Hubble constant Ho = 100 ho km s-1 Mpc-1
ho = 0.71± 0.07
Critical density of the Universe rhoo = 3 Ho2/8 pi G = 2.775 x 1011 ho2MsunMpc-3
= 1.879(3) x 10-26 ho2 kg m-3
Cosmological parameters
Hubble constant h = 0.71-0.03+0.04
Baryon density OmegaB = 0.044 ± 0.004
Matter density OmegaM = 0.27 ± 0.04
Dark energy density OmegaL = 0.73 ± 0.04
Total energy density OmegaL = 1.02 ± 0.02
Dark energy equation of state w < -0.78 (95 % CL)

Reference: Maroto and Ramírez, 2004, astro-ph/0409280

Photometry

Band System Mean wavelength (nm) FWHM (nm) Flambda (W m-2 nm-1) Flambda (W m-2 Hz-1)
U Johnson 1965
360
40
4.35 x 10-11 1.88 x 10-23
B Johnson 1965
440
100
7.20 x 10-11 4.44 x 10-23
V Johnson 1965
550
80
3.92 x 10-11 3.81 x 10-23
R Johnson 1965
700
210
1.76 x 10-11 3.01 x 10-23
I Johnson 1965
900
220
8.3 x 10-12 2.43 x 10-23
R Cousins 1976
647
151.5
I Cousins 1976
786.5
109.0
Notes: Flambda are the fluxes for a 0.0 mag star

Source: the Asiago Database on Photometric Systems

Spectroscopy

Main sky emission lines in the optical

Element Wavelength (nm)
OI 557.7338
NaI 588.9953
NaI 589.5923
OI 630.0304
OI 636.378
(from Osterbrock et al., 1996, PASP, 108, p. 277)

Night sky spectrum

At La Palma observatory (From Benn and Ellison, 1998, New Astronomy Reviews, 42, 503 -- astro-ph/9909153)

Atomic hydrogen (HI) balmer series (optical)

Wavelength (nm) Relative Intensity Transition Name Color
656.2852 180 3 -> 2 Halpha Red
656.272 120 3 -> 2 Halpha Red
486.133 80 4 -> 2 Hbeta Bluegreen (cyan)
434.047 30 5 -> 2 Hdelta Violet
410.174 15 6 -> 2 Hgamma Violet
397.0072 8 7 -> 2 Hdelta Violet
388.9049 6 8 -> 2 Hepsilon Violet
383.5384 5 9 -> 2 Hzeta Violet

References

  • Particle data book: pdg.lbl.gov
  • Handbook of Space Astronomy and Astrophysics, Martin V. Zombeck

  • Last update on 16/09/2004
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