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Questions tagged [brown-dwarfs]

Brown dwarfs are star-like objects that are too low in mass to fuse hydrogen-1 but still massive enough to fuse deuterium.

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Why are there fewer brown dwarfs than stars?

Lighter stars are more common than heavier stars, you'd think that this would make brown dwarfs more common than red dwarfs and yet they are less common by factors of a few. (e.g. see Table 5 of ...
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How long will Brown Dwarfs live?

Brown Dwarfs are a technical star because of their masses. If Red Dwarfs live for 10 trillion years, then how long could Brown Dwarfs live?
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What happens when a cool brown dwarf slowly accretes matter?

Let's imagine that we take a brown dwarf close to the minimum mass of a red dwarf. Then let's allow it a few quadrillion years to cool. Finally slowly accrete matter at a rate of say 1 Jupiter mass ...
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Would an extremely slowly forming star ignite?

Nuclear fusion requires extremely high temperatures and pressures, both of which are created by the collapse of protostars. But, what if the accretion of matter happened slowly enough that the core ...
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Why does a drop in gravitational energy result in star contraction

Consider a gas cloud that is radiating away heat. From virial theorem we see that if the cloud radiates away heat and loses energy this will cause its gravitational energy to drop. Why does this mean ...
DJA's user avatar
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Size of iron sphere with mass of our sun [closed]

What would be the diameter of a sphere of iron with the mass of our sun? Use standard density of metalic iron. I realize it would then collapse into a star in its own right and become much smaller as ...
Deschutes 's user avatar
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Super Heavy Brown Dwarf

As I understand black holes, they're considered "black" because the escape velocity is, or exceeds, the speed of light. Alternatively, the escaping light is redshifted infinitely. The Schwarzschild ...
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Where do brown dwarfs get deuterium from?

Brown dwarfs don't have a high enough temperature to begin fusing hydrogen, but they can fuse deuterium or burn lithium, according to Wikipedia. Where do they get the deuterium from? Is there just ...
D R Ball's user avatar
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Can the lithium test be applied to differentiate brown dwarfs from other substellar objects?

The lithium test is often used to differentiate brown dwarfs from low-mass M-type dwarfs (see e.g. Martin et al. (1994)), because brown dwarfs (at least the lower-mass ones) do not burn lithium, ...
HDE 226868's user avatar
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Could the estimated stellar mass for the Milky Way galaxy include brown dwarfs?

Trying to find an estimate for the stellar mass of the MW galaxy, I found this paper and the estimated stellar mass is $~6.5 \times 10^{10} M_{\odot}$. I was also trying to understand the methods used ...
Abanob Ebrahim's user avatar
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According to the initial mass function, should there be more brown dwarfs than red dwarfs?

According to the IMF and the stellar mass distribution, stars become more abundant the less massive they are. And while objects must have a mass > 0.075 solar mass to become a star, brown dwarfs with ...
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"Cloud maps" of a nearby brown dwarf: what do they actually show?

This paper recently made headlines: A global cloud map of the nearest known brown dwarf. I. J. M. Crossfield et al. Nature 505, 654–656 (30 January 2014). In short, they claim they've been able to ...
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