Re: 2 Questions for Astronomers

"BRAINIAC" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> A) Our sun is just an avergage star.

There are 71 stars within 20 light years of the solar system, of which only
4
(Alpha Centauri A, Sirius, Procyon, and Altair) are brighter than the sun.
Most are M dwarfs. Here's the list (from the hipparcos catalog)

           TYPE         DISTANCE (LY) MAGNITUDE    Name
HIP70890    M5Ve        4.2 +/- 0.00  11.0  Alpha Centauri C (Proxima)
HD128621    K1V         4.4 +/- 0.00   1.4  Alpha Centauri B
HD128620    G2V         4.4 +/- 0.01  -0.0  Alpha Centauri A (Rigil Kent)
HIP87937    sdM4        6.0 +/- 0.04   9.5  Barnard's star
HD95735     M2V         8.3 +/- 0.02   7.5  Ursa Major
HD48915     A0m...      8.6 +/- 0.01  -1.4  Alpha Canis Majoris (Sirius)
HIP92403    M3.5Ve      9.7 +/- 0.04  10.4  Sagittarius
HD22049     K2V         10.5 +/- 0.07   3.7  Epsilon Eridani
HD217987    M2/M3V      10.8 +/- 0.07   7.3  Sculptor
HIP57548    M4.5V       10.9 +/- 0.05  11.1  Virgo
HD201091    K5V         11.4 +/- 0.06   5.2  61 Cygni A
HD61421     F5IV-V      11.4 +/- 0.12   0.4  Alpha Canis Minoris (Procyon)
HD201092    K7V         11.5 +/- 0.06   6.0  61 Cygni B
HD173740    K5          11.5 +/- 0.10   9.7  Draco
HD173739    K5          11.7 +/- 0.05   8.9  Draco
HD1326      M1V         11.7 +/- 0.09   8.1  Andromeda
HD209100    K5V         11.9 +/- 0.04   4.7  Epsilon Indi
HD10700     G8V         11.9 +/- 0.05   3.5  Tau Ceti
HIP5643     M5.5Ve      12.2 +/- 0.04  12.1  Cetus
HIP36208    M5          12.4 +/- 0.04   9.8  Luyten's star
HD33793     M0V         12.8 +/- 0.06   8.9  Kapteyn's star
HD202560    M1/M2V      12.9 +/- 0.05   6.7  Microscopium
HD239960    M2V         13.1 +/- 0.05   9.6  Kruger 60
HIP30920    M4.5Ve      13.5 +/- 0.07  11.1  Monoceros
HIP72511    M           13.9 +/- 4.08  11.7  Hydra
HIP80824    M4          13.9 +/- 0.30  10.1  Ophiuchus
HIP80825    A5          13.9 +/- 0.30  11.2  Ara
HD225213    M2V         14.3 +/- 0.05   8.6  Sculptor
HIP15689                14.4 +/- 0.08  12.2  Eridanus
HIP3829     DG          14.4 +/- 0.04  12.4  Van Maanen 2
HIP72509    M           14.7 +/- 0.08  12.1  Hydra
HIP86162    M3.5Vvar    14.8 +/- 0.05   9.2  Draco
HIP85523    K5          14.8 +/- 0.06   9.4  Ara
HIP114110               15.1 +/- 0.10  12.2  Aquarius
HIP57367    DC:         15.1 +/- 0.25  11.5  Musca
HIP113020   M5          15.4 +/- 0.21  10.2  Aquarius
HIP54211    M2Vvar      15.8 +/- 0.07   8.8  Ursa Major
HD88230     K8V         15.9 +/- 0.11   6.6  Ursa Major
HIP82725                16.1 +/- 1.60  11.7  Ara
HIP85605                16.1 +/- 0.30  11.4  Hercules
HD204961    M1V         16.1 +/- 0.13   8.7  Grus
HIP86214    M5          16.5 +/- 0.04  10.9  Scorpius
HD26965     K1V         16.5 +/- 0.07   4.4  Omicron Eridani B
HIP112460   M4.5Ve      16.5 +/- 0.24  10.3  Lacerta
HD165341    K0V SB      16.6 +/- 0.12   4.0  70 Ophiuchi
HD187642    A7IV-V      16.8 +/- 0.07   0.8  Alpha Aquilae (Altair)
HIP1242     M:          17.0 +/- 0.29  11.5  Cetus
HIP57544    M4          17.6 +/- 0.07  10.8  Camelopardalis
HD119850    M3V         17.8 +/- 0.07   8.5  Bootes
HIP103039               18.0 +/- 0.19  11.4  Capricornus
HIP21088                18.0 +/- 0.32  10.8  Camelopardalis
HD265866    K:...       18.0 +/- 0.10   9.9  Gemini
HIP53020    M4:         18.4 +/- 0.28  11.6  Leo
HD36395     M1V         18.6 +/- 0.14   8.0  Orion
HD152751    M3Ve        18.8 +/- 0.44   9.0  Ophiuchus
HD185144    K0V         18.9 +/- 0.10   4.7  Sigma Draconis
HIP96101    F0          18.9 +/- 0.10  10.6  Sagittarius
HD42581     M1/M2V      18.9 +/- 0.16   8.2  Canis Major
HIP26857    M5          18.9 +/- 0.26  11.6  Orion
HIP86990    M5          19.0 +/- 0.07  10.8  Pavo
HD180617    M3.5V       19.2 +/- 0.10   9.1  Aquila
HD131977    K4V         19.3 +/- 0.14   5.7  Libra
HIP37766    M4.5Ve      19.4 +/- 0.08  11.2  Canis Minor
HIP76074    M0          19.4 +/- 2.35   9.3  Lupus
HD4614      G0V SB      19.5 +/- 0.24   3.5  Eta Cassiopeiae
HD156026    K5V         19.5 +/- 0.26   6.3  Ophiuchus
HIP117473   M2V         19.5 +/- 0.15   9.0  Pisces
HD155885    K2:III:     19.6 +/- 0.08   4.3  36 Ophiuchi
HD191408    K2V         19.8 +/- 0.11   5.3  Sagittarius
HD20794     G8V         19.8 +/- 0.52   4.3  e Eridani
HD190248    G5IV-Vvar   20.0 +/- 0.25   3.5  Delta Pavonis