Questions tagged [brown-dwarf]

Questions about sub-stellar objects that are like stars but never achieve permanent nuclear fusion because they are too low-mass.

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What would happen if a low-mass primordial black hole was captured by a brown dwarf or planet mass object?

Prompted by a recent PBS SpaceTime video The video in question discusses what would happen if a low-mass (asteroid-mass) primordial black hole were captured in the core of a Sun-like star (a so-called ...
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How would we tell the difference between low mass objects that formed by direct collapse or in an accretion disk?

In this question about rogue planet/sub brown detection there are a couple of comments about classification of non-stellar, low mass, free floating objects. Part of one of the answers is - Some "...
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Life around a former brown dwarf

Imagine a brown dwarf of any given mass (between the usual 13j - ~90j mark). It orbits within the outer edge of a reasonably quiet star's habitable zone. Within about 55 million years, it stops fusing ...
Kazon's user avatar
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Sub brown dwarf cores

I’ve heard that the cores of sub-brown dwarfs (sub brown dwarfs mass objects that form the same way as stars and brown stars instead of forming like planets do.) are different from that of gas giants. ...
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4 votes
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Do brown dwarf 'stars' fuse simple hydrogen (p-p reaction) at all?

I sometimes read that only deuterium-deuterium fusion can occur in brown dwarfs... And maybe deuterium-proton fusion? To He-3? In order to overcome Coulombic repulsion and, occasionally, fuse, protons ...
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How much of the hydrogen in our sun will never participate in fusion? What about larger stars? [duplicate]

From what I gather, only red dwarf stars are fully convective, and will use up pretty much all of their hydrogen.... Is there a chart or list somewhere that shows the percentage of hydrogen that is ...
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Mass range of a sub-brown dwarf

Sub-brown dwarfs are celestial object that have planetary mass or are termed "Planetary mass object/planemos". They do not lie in the range 13-80 MJ that defines "normal" brown ...
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Does the mass-luminosity relation work for brown dwarfs?

There is a mass-luminosity relationship of the form $L \propto M^a$, where $a = 3.5$, that is is applicable to main-sequence stars. Is there a similar relationship that holds for brown dwarfs?
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What is going on with this (sub?) brown dwarf WISEPA J174124.26+255319.5?

In this Wikipedia article, it details about a T9 class brown dwarf named WISEPA J174124.26+255319.5. Apparently, this brown dwarf has 0.95 Jupiter masses, and 0.4 Jupiter radii (with rather low error)...
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How do I code the formula for the minimum mass of a stellar fragment from Whitworth & Stamatellos, 2006?

I was researching the formation of brown dwarfs, and I stumbled into the paper "The minimum mass for star formation, and the origin of binary brown dwarfs", and I am attempting to code a ...
Ankit Biswas's user avatar
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What is it like to see a brown dwarf turn into a star?

Brown dwarfs/failed stars can actually become stars, if they exceed a mass limit of about 80 Jupiter masses. This is when the internal pressure and temperature at the core become high enough to ...
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Can a brown dwarf accrete enough mass from red giant to become a star?

Let's assume a brown dwarf is on orbit around a main sequence star. Than the star becomes a red giant. Let's assume the brown dwarf has "the right" orbit and can syphon matter from the red ...
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How do I calculate the flux density of a substellar object?

I am currently trying to generate photometric passband colors for brown dwarfs and planets generated through MESA (Modules for Experiments in Stellar Astrophysics). I believe I understand the ...
Ankit Biswas's user avatar
18 votes
1 answer
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How can a brown dwarf be more massive than a star?

SDSS J0104+1535 is about 90 times more massive than Jupiter, making it the heaviest known brown dwarf. EBLM J0555-57Ab has a mass of about 85.2±4 Jupiter masses, or 0.081 Solar masses. I am confused. ...
Binita Rimal's user avatar
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Can we use atmospheric retrieval techniques on stars?

Although there are lots of examples of atmospheric retrieval techniques being used on exoplanets, and recently brown dwarfs, I can't find any mention of atmospheric retrieval techniques being used on ...
Bad_physicist's user avatar
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How luminous does a brown dwarf have to be to illuminate an Earth-sized planet with 0.5 lux at 2,000,000 kilometers away?

A brown dwarf is a deuterium-fusing substellar object, and, in the cases of the larger ones, a lithium-fusing one. They often emit electromagnetic radiation in frequencies that humans cannot see. ...
KEY_ABRADE's user avatar
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Brown Dwarf Sun: How dim can a star be in the visible spectrum and still provide enough heat for a planet to be habitable?

After reading this question on wordbuilding. I saw that a brown dwarf emits most of its energy in the infrared which made me wonder: How bright would such a star appear from it's exoplanet in the ...
SurpriseDog's user avatar
17 votes
1 answer
630 views

Is stellar ignition all-or-nothing?

The boundary between brown dwarfs and stars is around 80 Jupiter masses. Only stars generate a self-sustaining hydrogen fusion, although brown dwarfs sometimes fuse lithium and deuterium. Is hydrogen ...
Kevin Kostlan's user avatar
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Power law of object mass in Milky way

Red dwarfs are more common than larger stars. Does this trend continue to smaller objects? If you take every "condensed object" from dust grains through asteroids, planets, and stars in the ...
Kevin Kostlan's user avatar
4 votes
1 answer
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At what point does an astronomical body's surface stop being gas giant-like and start being sun-like?

I've generally seen brown dwarfs depicted as more massive and slightly wider Jupiters in varying colors with banded cloud structures, sometimes hot enough to be visible glowing. I've also seen red ...
Adam Lincoln Steele's user avatar
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1 answer
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Do brown dwarfs have starspots?

Do lithium-burning brown dwarfs (65+ Jupiter masses) have starspots too or do they occur only on hydrogen-burning stars?
John's user avatar
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Can dark matter be normal matter after all? [duplicate]

MACHO's and RAMBO's are both baryonic (and leptonic) forms of matter that can't be observed by their nature. They barely emit or reflect light. Black holes, neutron stars, or brown dwarfs (or groups ...
Deschele Schilder's user avatar
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Can (neo)WISE detect the coolest Y-dwarfs?

The WISE telescope discovered some Y brown dwarfs already. Is the neoWISE mission able to detect even the coolest ones (such as Y9 dwarfs) within five light-years distance? If so, the telescope would ...
John's user avatar
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13 votes
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Are Brown and Sub-Brown Dwarfs secretly more common than stars?

I recently heard that Red Dwarfs are the most common type of star, and low-mass Red Dwarfs are the most common type of Red Dwarf. This seems to imply a generic trend that the lower the mass, the more ...
cowlinator's user avatar
4 votes
1 answer
206 views

Is it dangerous to look at an L-type brown dwarf from too close?

Are some L-type brown dwarves bright enough so that it would be dangerous to the eyes if one looked at them from habitable distance or closer? If not, are the weakest M-type stars undangerous to look ...
Giovanni's user avatar
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Maximum and minimum masses and sizes of giant planets?

What are the minimum & maximum masses and diameters of giant planets? Minimum end of the scale Earth has mass of 1 Earth mass and a mean radius of 6,371.0 kilometers, and thus a mean diameter of ...
M. A. Golding's user avatar
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1 answer
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Orbit of Luhman 16?

I am studying some binary stars and brown dwarfs. Some orbits are known and easy to find, like Alpha Centauri. However, when I look for the orbital characteristics of Luhman 16 (AB), I only get the ...
WarpPrime's user avatar
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5 votes
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Why do degenerate objects get hotter as more mass is added?

After reading this question, I decided to post a question about degeneracy. I've seen simulations on large, $15\text{+ }M_J$ objects that are accreting mass. They do not grow in radius, instead they ...
slowerthanstopped's user avatar
2 votes
1 answer
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Would dropping a white dwarf or a "still-hot" stellar core into a large planet or brown dwarf create a star?

In the Wikipedia article about stellar engineering, I found this quote: In The Saga of the Seven Suns, by Kevin J. Anderson, humans are able to convert gas giant planets into stars through the use of ...
WarpPrime's user avatar
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How do we know that 2MASS J0523-1403 is a red dwarf?

I was reading about red dwarfs, and stumbled upon this article about the least massive red dwarf, and noticed several peculiarities: The spectral type is L2.5 The luminosity class is V The mass is 67....
WarpPrime's user avatar
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2 votes
1 answer
119 views

Is there a luminosity class for brown dwarfs?

I've been reading about brown dwarfs, and checking their spectral types, and I noticed that they do not have a luminosity class (V, VI, etc). So I am wondering, do brown dwarfs have a luminosity class,...
WarpPrime's user avatar
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-1 votes
1 answer
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If the Earth circled a red dwarf/giant or a brown dwarf, would its sky still look blue? [duplicate]

I have the impression that in brown dwarf and weak red dwarf systems, everything looks more reddish on a planet, including its atmosphere regardless of composition. Suppose there's a planet having an ...
Greenhorn's user avatar
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1 answer
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Can red dwarf stars have a spectral type of L?

We have the "normal" main sequence stars, OBAFGKM. Below K and M are the brown dwarfs, L,T, and Y. Zooming into the area at the edges of M and L, we have spectral types M9, M9.5, L0, and L1. ...
WarpPrime's user avatar
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4 votes
1 answer
66 views

Why is WISE J0521+1025's distance so uncertain?

If you look at the Wikipedia page List of nearest stars and brown dwarfs , you'll notice that all stars mentioned in the list have a very precise value; all are $\pm0.02$ ly (except for GJ 1005, but ...
WarpPrime's user avatar
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19 votes
2 answers
4k views

Can lightning occur in stars like the Sun?

In the Wikipedia article about lightining, the following explanation is given about the electrification process in clouds: The details of the charging process are still being studied by scientists, ...
ksousa's user avatar
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16 votes
1 answer
343 views

Do brown dwarfs have stripes?

Brown dwarfs (BD) are often depicted with stripes. brown dwarf Jupiter Pictures of BD resemble Jupiter but brown dwarfs ...
Heopps's user avatar
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1 vote
2 answers
78 views

Is there a way to know if there are/are not solar-system-like systems of objects without a star?

There's an extremely high amount of variation in All of Known Existence. We do see many many stars, with an extensive amount of evidence for planets orbiting around stars. However, is there are way to ...
Facey Neck's user avatar
2 votes
2 answers
404 views

Can a high enough density ignite a gas giant into a brown dwarf?

I wonder whether the nuclear fusion of brown dwarfs and more massive stars really depends on their mass only or if it could also start nuclear fusion if it is dense enough but not as massive as brown ...
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4 votes
1 answer
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Where are the two recently confirmed unusual brown dwarfs?

The News report of two confirmed unusual T-type brown dwarfs but they don't tell where in space or on the night sky they were found or how far they are from the Earth/Sun. The brown dwarfs are WISE ...
Ioannes's user avatar
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9 votes
1 answer
721 views

Why is detecting brown dwarfs difficult?

Why is detecting brown dwarf stars tedious and not always successful? They emit light in the infrared region, and given that we're surrounded by state-of-the-art technology in space today, why haven't ...
Pranay's user avatar
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12 votes
1 answer
415 views

Is there a relation between mass, radius, and luminosity in deuterium-burning brown dwarfs?

I'm a worldbuilder and my setting has a lot of brown dwarfs. While I'm trying to keep my setting as science-compliant as possible, I can't seem to find any resources for brown dwarfs like there are ...
TerranAmbassador's user avatar
2 votes
1 answer
297 views

Why have brown dwarf classes been dubbed L, T and Y?

The classes used to categorize stars (O, B, A, F, G, K, M) are in a bizarre order for historical reasons. Stars were labeled based on the spectral lines that were visible, then the categories were put ...
usernumber's user avatar
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How are Y-dwarf spectral subtypes defined?

It is often stated that the spectral subtype indicates the relative position between spectral types, e.g. G5 being halfway from the start of spectral type G to the beginning of spectral type F. Given ...
user avatar
0 votes
1 answer
223 views

Would it be possible for life found on moon of rogue planet

I have heard that there are at least three Basic requirement for life exist in the universe, they are: Source of Energy Complex chemistry (including solvent/medium for chemical reaction) Protection ...
C.Calvert's user avatar
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4 votes
1 answer
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Brown Dwarf Cloud Models

There has been research that suggests that the changing brightness of Brown Dwarves are due to bands of Iron/Silicate clouds. Several models have been made that supports that hypothesis. My question ...
Hippeus_Lancer's user avatar
5 votes
1 answer
182 views

Are we looking for brown dwarfs where the dark matter has to be?

We have been repeatedly assured that their ain't enough brown dwarfs to account for all the dark matter in our galaxy. My question is have we been looking in the right places? Or in more detail. ...
Blame's user avatar
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13 votes
3 answers
692 views

Existence of planets larger than their host star?

The mass region of objects between ~ 0.5 Jupiter masses and 80 Jupiter masses (gas giants through to brown dwarfs and red dwarfs) is typified by an almost flat relationship with object diameter. There ...
Ingolifs's user avatar
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6 votes
1 answer
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Are brown dwarfs which don't sustain any fusion considered stars?

I was reading about the coolest stars, and was surprised to find about stars with a surface temperature lower than a candle, like 2MASS 0939-2448 A/B, of about 100 Celsius like CFBDSIR 1458+10B and ...
Pablo's user avatar
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3 votes
1 answer
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Brown dwarf magnetic activity

I have not been able to find an answer to my question through google, and therefore ask it on this medium. Do brown dwarfs have spots and faculae similar to other heavier stars?
user4437416's user avatar
1 vote
1 answer
163 views

Are brown dwarf masses notoriously difficult to measure?

The Next Big Future article Rogue Exoplanet 12.7 times bigger than Jupiter is 20 light years away SIMP J01365663+0933473 has a magnetic field more than 200 times stronger than Jupiter’s. The object ...
uhoh's user avatar
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