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RE: starship-design: Stars_within_16_light_years_of_the_Sun
> From lparker@cacaphony.net Mon Jun 23 02:29:40 1997
>
> Zenon,
>
> No, it is quite correct.
>
> Lee Parker
>
> -----Original Message-----
> From: Zenon Kulpa [SMTP:zkulpa@zmit1.ippt.gov.pl]
>
> > From: "L. Parker" <lparker@cacaphony.net>
> >
> > Stars within 16 light years of the Sun
> > NAME DISTANCE SPECTRAL APPARENT VISUAL
> > (in parsecs) TYPE MAGNITUDE MAGNITUDE
> > Sun N/A G2 V -26.72 4.85
> > Proxima Centauri 1.3 M6 V 11.05 15.49
> > Alpha Centauri A 1.33 G2 V -0.01 4.37
> > Alpha Centauri B 1.83 K1 V 1.33 5.71
> >
> There is most probably an error - the distance to A and B
> is nearly the same, certainly much less than between any of them
> and Proxima, so there should probably be 1.33 parcecs for both.
>
> -- Zenon
>
Sorry, but this MUST be in error.
Your data gives B farther away than A by 0.5 ps, that is 1.6 ly,
and at the same distance as to Barnard.
And both these are certainly not true.
I am also including some data from some other sources for comparison below.
Note also differences concerning spectral types and magnitudes
between the sources.
NAME DISTANCE SPECTRAL APPARENT VISUAL
(ps/ly) TYPE MAGNITUDE MAGNITUDE
L. Parker source:
-----------------
Proxima Centauri 1.3 M6 V 11.05 15.49
Alpha Centauri A 1.33 G2 V -0.01 4.37
Alpha Centauri B 1.83 K1 V 1.33 5.71
Barnard's Star 1.83 M4 V 9.54 13.22
http://www.essex1.com/people/speer/stars.html:
----------------------------------------------
Proxima Centauri (1.29)/4.2 M5e 11.3
Alpha Centauri A (1.32)/4.3 G0 .33
Alpha Centauri B (1.32)/4.3 K5 1.70
Barnard's Star (1.83)/5.96 M5 9.5
http://monet.physik.unibas.ch/~schatzer/Alpha-Centauri.html:
------------------------------------------------------------
Proxima Centauri (1.29)/4.22 M5e
Alpha Centauri A (1.33)/4.35 G2
Alpha Centauri B (1.33)/4.35 K1
Separation A/B (current): 23 AU = 0.00001 ps
The units:
----------
AU = 149 598 770 km
ly = 9.4543*10^12 km = 63197.7 AU = 0.3066 ps
ps = 30.8361*10^12 km = 206125.7 AU = 3.2616 ly
-- Zenon