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Fraser
2006-Oct-20, 12:53 AM
Astronomers have directly imaged a brown dwarf companion to the star HD 3651. This star is already known to host an extrasolar planet - less massive than Saturn, but sitting within the orbit of Mercury. HD 3651 is slightly less massive than the Sun, and is located 36 light-years away in the constellation Pisces. The brown dwarf, or HD 3651B, is probably between 20 and 60 Jupiter masses, and has a temperature between 500 and 600 degrees Celsius.

Read the full blog entry (http://www.universetoday.com/2006/10/19/brown-dwarf-companion-seen-directly/)

edit: I fixed the slip about Solar vs. Jupiter masses. (-A)

jonfr
2006-Oct-20, 07:36 AM
I wonder if there is a brown dwarf around our solar system.

Joca
2006-Oct-20, 08:21 AM
I wonder if there is a brown dwarf around our solar system.

More on the possible role of HD 3651 B as an 'Extrasolar Nemesis' in XSM (http://www.xsmagazine.co.nr) [look up HD 3651 B in the index].

Cheers,
Jovan

edit: ..and of course - http://www.bautforum.com/showthread.php?t=47036&highlight=3651 :D

snabald
2006-Oct-20, 09:26 AM
Astronomers have directly imaged a brown dwarf companion to the star HD 3651. This star is already known to host an extrasolar planet - less massive than Saturn, but sitting within the orbit of Mercury. HD 3651 is slightly less massive than the Sun, and is located 36 light-years away in the constellation Pisces. The brown dwarf, or HD 3651B, is probably between 20 and 60 solar masses, and has a temperature between 500 and 600 degrees Celsius.

Read the full blog entry (http://www.universetoday.com/2006/10/19/brown-dwarf-companion-seen-directly/)

probably between 20 and 60 solar masses?

Is this a typo?

galacsi
2006-Oct-20, 09:32 AM
probably between 20 and 60 solar masses?

Is this a typo?

Yes it is between 20 and 60 Jovian masses.

Joca
2006-Oct-20, 09:33 AM
Of course :) In the text it says '20 and 60 Jupiter masses'.. Wow, that would be great, a whole new class of dwarf stars ;)

antoniseb
2006-Oct-20, 12:27 PM
We are slowly building our inventory of the diverse types of planetary systems that we know about. This one is interesting if for no other reason than providing a visible example of a T-dwarf for future study with better instruments.

SneakyPete
2006-Oct-20, 12:48 PM
You are correct...the brown dwarf star is 20 to 60 Jupiter masses.

John Mendenhall
2006-Oct-20, 01:03 PM
Great typo. I rather liked the idea of a brown dwarf of 20 to 30 solar masses. Must have been left over from a previous universe with different physical constants. In this universe it would be a supernova candidate.

A.DIM
2006-Oct-20, 02:32 PM
I wonder if there is a brown dwarf around our solar system.

Great question!

I've been asking the same for a number of years now...

And after much reading and research, I'd say yes.

John Mendenhall
2006-Oct-20, 02:43 PM
I'd say no. Wouldn't it stand out like a sore thumb, especially in the infrared?

ioresult
2006-Oct-20, 02:57 PM
maybe you should also correct the typo on the main page, it still says "solar masses"

Joca
2006-Oct-20, 03:02 PM
I'd say no. Wouldn't it stand out like a sore thumb, especially in the infrared?

That's right.. It would probably be invisible to the naked eye, but it should be easily detected with one of the space telescopes, right?

John Mendenhall
2006-Oct-20, 04:32 PM
Oh, Lordy, Universe Today does make me stop and think. Here is the location of the Wiki article on Nemesis.

http://en.wikipedia.org/wiki/Nemesis_%28star%29

Looks like the jury is still out. Except it's probably not 20 to 30 solar masses.

antoniseb
2006-Oct-20, 04:41 PM
The jury came back with the Hipparcos probe's data. It is possible that an appeal can be made with GAIA, LSST, WISE, etc.

John Mendenhall
2006-Oct-20, 04:53 PM
I don't know if we should hope for or against a reversal on appeal. If there is a Nemesis, and it's not due back for 20 million years, then we can probably handle the next apparition.

antoniseb
2006-Oct-20, 05:20 PM
The first observation leading to a Nemesis hypothesis was the supposed regularity of mass extinctions. From what I've seen that observation is questionable at this time, for example Wiki says:

However, the period of oscillation is not well-constrained observationally, and may differ from the needed 26 million years by as much as 40%.
So, what we are left with is a thought that a massive object co-moving with the Sun has not bee ruled out completely, but no actual evidence supporting that it might be there. By 2011, we should be able to rule out any object within a light year and more massive than Neptune.

Joca
2006-Oct-20, 05:24 PM
From A.J. Burgasser's paper:

"This hypothesized companion to the Sun has been proposed to explain apparent periodicities in massive extinctions, terrestrial cratering rates, reversals of Earth's magnetic fields and, more recently, the peculiar orbits of inner Oort cloud planetoids."

It seems there are a couple of more questions, beside these, that could be answered by the existence of Nemesis.

Another interesting link:

http://en.wikipedia.org/wiki/Nemesis_%28Asimov%29

:))

Fraser
2006-Oct-20, 07:30 PM
Slip of the brain there. Yeah, it's Jovian masses...

jseefcoot
2006-Oct-23, 07:56 PM
I was wondering whether or not a dwarf could have an eccentric orbit, which led me to thinking about where we do the searching.

When astronomers perform these types of surveys, do they only investigate the plane of our solar system, or do they search all around, in a 'bubble'?

If a dwarf was not located on the ecliptic, might we miss seeing it? That is, if we only look along the plane of the ecliptic.

A.DIM
2006-Oct-23, 08:19 PM
From what I understand, not only are most searches within the ecliptic, there remains a not insignificant portion of the sky yet to be scanned within the ecliptic.