Brightest stars we see from here

Wags just asked a real good question -
>I wonder if Tau CMa is the brightest absolute magnitude star visible
>from the northern hemisphere...

Mark, we discussed this very point in May 02 right here on TAC. You'd
asked how the Sun would look if placed out there with neighboring
stars. I got the bit in my teeth and got some answers
http://observers.org/tac.mailing.list/2002/May/0760.html

At the end of that story, I went over your question, way back then -

I tell my students all the time about how the nekked eye stars are
nekked eye from here because they're huge beacons, much brighter than
our Sun. Then there are the nekked eye winners. Deneb is an awesome
engine, 1600 ly from here, at Mv -7.5. some 60,000 solar
luminosities. Keep your starship away from there. I'd long thought
Deneb was the winner among the intrinsically brightest stars from
here, but no the blue ribbon goes to iota1 Sco, the easternmost star
in Scorpius' tail as it curves around. That sucker is going at Mv
-8.6, over 150,000 times the output of our friendly neighborhood
yellow dwarf. It's some 4,800 lightyears away.
(These numbers are from the Peterson guide, Stars and Planets,
Pasachoff's book, crosschecked in Sky Catalogue 2000.0.)

Kingsley made excellent use of alliteration describing Eta Carinae ...
>there must be an incredibly energetic hypergiant at the heart of the
>homunculus.

But to our knowledge the bull goose star for a long while was the
Pistol Star. Seen from Earth but not by mortals.
http://hubblesite.org/newscenter/newsdesk/archive/releases/1997/33/
Working at 10 million solar luminosities. Cross my heart on the
number of zeroes. More than 150x what Deneb's doing, 5x Eta Car at
its peak.

25,000 ly's away, toward the center of the galaxy, in Sagittarius. So
much dust in between that it's flat not available in visible light.
The Hubble picked it up in infrared. If not for the dust, it'd be 4th
magnitude from here, at that distance. And recently there was a story
somewhere about another star outshining the Pistol Star. I'm keeping
my distance.

DDK

-- 
Jamie Dillon <*> speech pathologist
jamie_dillon@No-Spam
" ... " - Harpo Marx