Sfdwhf

Concept of linear mappings are confusing me

I’m planning on buying a laser printer but concerned about the life cycle of toner in the machine

What are these boxed doors outside store fronts in New York?

Is Social Media Science Fiction?

Why did the Germans forbid the possession of pet pigeons in Rostov-on-Don in 1941?

How do I create uniquely male characters?

Can I make popcorn with any corn?

How can bays and straits be determined in a procedurally generated map?

Can an x86 CPU running in real mode be considered to be basically an 8086 CPU?

What is the offset in a seaplane's hull?

Is it possible to do 50 km distance without any previous training?

How can the DM most effectively choose 1 out of an odd number of players to be targeted by an attack or effect?

How is this relation reflexive?

TGV timetables / schedules?

Set-theoretical foundations of Mathematics with only bounded quantifiers

Possibly bubble sort algorithm

How did the USSR manage to innovate in an environment characterized by government censorship and high bureaucracy?

Download, install and reboot computer at night if needed

How much RAM could one put in a typical 80386 setup?

How to type dʒ symbol (IPA) on Mac?

Example of a relative pronoun

Why are only specific transaction types accepted into the mempool?

Schwarzchild Radius of the Universe

I probably found a bug with the sudo apt install function

black dwarf stars and dark matter

How can Y-dwarf stars have such a low temperature?Dark Matter 'Stars'Dark matter and black holeDid dark matter cause the formation of the Solar System?Are black holes in a binary system with white holes, and are they both wormholes?Do clouds of dark matter cool and contract?Direct Dark Matter Detection: relative velocity between WIMPs & NucleiWhen and where was WIMP dark matter formed?Overlap between experimental searches for axion and WIMP dark matterWhat is the theoretical lower mass limit for a white dwarf?

2

$begingroup$

Today we understand that a black dwarf star represents a hypothetical star that is the result of the complete consumption of the energy of a white dwarf which is the remnant of a star of little or half mass (1 solar mass), once all its hydrogen has been consumed or expelled. This rest is a dense piece of "degenerated matter" that slowly cools and crystallizes by emission of heat radiation. So, if these objects (not yet observed) do not emit light but interact gravitationally with the surrounding matter, we can not say that dark matter may be black dwarf stars that are contained within the galactic halo? To discard weak interaction particles such as WIMP's or its opposite, the MACHO's ("massive compact halo objects")

astrophysics astronomy dark-matter stars wimps

share|cite|improve this question

asked 5 hours ago

jormansandovaljormansandoval

923719

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I'm pretty sure the "degenerated matter" of the black dwarf is still made of baryons, so it is not dark matter.
  $endgroup$
  – N. Steinle
  4 hours ago
  

  
  
  
  

add a comment | 

2

$begingroup$

Today we understand that a black dwarf star represents a hypothetical star that is the result of the complete consumption of the energy of a white dwarf which is the remnant of a star of little or half mass (1 solar mass), once all its hydrogen has been consumed or expelled. This rest is a dense piece of "degenerated matter" that slowly cools and crystallizes by emission of heat radiation. So, if these objects (not yet observed) do not emit light but interact gravitationally with the surrounding matter, we can not say that dark matter may be black dwarf stars that are contained within the galactic halo? To discard weak interaction particles such as WIMP's or its opposite, the MACHO's ("massive compact halo objects")

astrophysics astronomy dark-matter stars wimps

share|cite|improve this question

asked 5 hours ago

jormansandovaljormansandoval

923719

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I'm pretty sure the "degenerated matter" of the black dwarf is still made of baryons, so it is not dark matter.
  $endgroup$
  – N. Steinle
  4 hours ago
  

  
  
  
  

add a comment | 

$begingroup$

Today we understand that a black dwarf star represents a hypothetical star that is the result of the complete consumption of the energy of a white dwarf which is the remnant of a star of little or half mass (1 solar mass), once all its hydrogen has been consumed or expelled. This rest is a dense piece of "degenerated matter" that slowly cools and crystallizes by emission of heat radiation. So, if these objects (not yet observed) do not emit light but interact gravitationally with the surrounding matter, we can not say that dark matter may be black dwarf stars that are contained within the galactic halo? To discard weak interaction particles such as WIMP's or its opposite, the MACHO's ("massive compact halo objects")

astrophysics astronomy dark-matter stars wimps

share|cite|improve this question

asked 5 hours ago

jormansandovaljormansandoval

923719

$endgroup$

share|cite|improve this question

asked 5 hours ago

jormansandovaljormansandoval

923719

share|cite|improve this question

asked 5 hours ago

jormansandovaljormansandoval

923719

asked 5 hours ago

jormansandovaljormansandoval

923719

asked 5 hours ago

jormansandovaljormansandoval

923719

1 Answer
1

active

oldest

votes

2

$begingroup$

Three reasons:

1. As you correctly point out, black dwarfs are "hypothetical objects". There has been insufficient time since the first stars were born for white dwarfs to cool below about 3000 K. i.e. Whilst there are faint white dwarfs with luminosities below a few $10^{-5} L_{odot}$, they are not invisible.




2. Microlensing experiments rule out "massive compact halo objects", like cold white dwarfs or black holes as a significant contributor to dark matter.




3. Most of the dark matter needs to be non baryonic and to interact very weakly with normal matter in order to form the structures that we see today in the universe; and to reconcile the inferred primordial abundances of helium, deuterium and lithium with the total amount of matter deduced to be in galaxies and clusters of galaxies. Cold white dwarfs are baryonic, so cannot represent the bulk of dark matter.

share|cite|improve this answer

answered 4 hours ago

Rob JeffriesRob Jeffries

70.3k7142243

$endgroup$

add a comment | 

Your Answer

StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "151"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name

Email

Required, but never shown

StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphysics.stackexchange.com%2fquestions%2f471183%2fblack-dwarf-stars-and-dark-matter%23new-answer', 'question_page');
}
);

Post as a guest

Name

Email

Required, but never shown

2

$begingroup$

Three reasons:

1. As you correctly point out, black dwarfs are "hypothetical objects". There has been insufficient time since the first stars were born for white dwarfs to cool below about 3000 K. i.e. Whilst there are faint white dwarfs with luminosities below a few $10^{-5} L_{odot}$, they are not invisible.




2. Microlensing experiments rule out "massive compact halo objects", like cold white dwarfs or black holes as a significant contributor to dark matter.




3. Most of the dark matter needs to be non baryonic and to interact very weakly with normal matter in order to form the structures that we see today in the universe; and to reconcile the inferred primordial abundances of helium, deuterium and lithium with the total amount of matter deduced to be in galaxies and clusters of galaxies. Cold white dwarfs are baryonic, so cannot represent the bulk of dark matter.

share|cite|improve this answer

answered 4 hours ago

Rob JeffriesRob Jeffries

70.3k7142243

$endgroup$

add a comment | 

2

$begingroup$

Three reasons:

1. As you correctly point out, black dwarfs are "hypothetical objects". There has been insufficient time since the first stars were born for white dwarfs to cool below about 3000 K. i.e. Whilst there are faint white dwarfs with luminosities below a few $10^{-5} L_{odot}$, they are not invisible.




2. Microlensing experiments rule out "massive compact halo objects", like cold white dwarfs or black holes as a significant contributor to dark matter.




3. Most of the dark matter needs to be non baryonic and to interact very weakly with normal matter in order to form the structures that we see today in the universe; and to reconcile the inferred primordial abundances of helium, deuterium and lithium with the total amount of matter deduced to be in galaxies and clusters of galaxies. Cold white dwarfs are baryonic, so cannot represent the bulk of dark matter.

share|cite|improve this answer

answered 4 hours ago

Rob JeffriesRob Jeffries

70.3k7142243

$endgroup$

add a comment | 

$begingroup$

Three reasons:

1. As you correctly point out, black dwarfs are "hypothetical objects". There has been insufficient time since the first stars were born for white dwarfs to cool below about 3000 K. i.e. Whilst there are faint white dwarfs with luminosities below a few $10^{-5} L_{odot}$, they are not invisible.




2. Microlensing experiments rule out "massive compact halo objects", like cold white dwarfs or black holes as a significant contributor to dark matter.




3. Most of the dark matter needs to be non baryonic and to interact very weakly with normal matter in order to form the structures that we see today in the universe; and to reconcile the inferred primordial abundances of helium, deuterium and lithium with the total amount of matter deduced to be in galaxies and clusters of galaxies. Cold white dwarfs are baryonic, so cannot represent the bulk of dark matter.

share|cite|improve this answer

answered 4 hours ago

Rob JeffriesRob Jeffries

70.3k7142243

$endgroup$

share|cite|improve this answer

answered 4 hours ago

Rob JeffriesRob Jeffries

70.3k7142243

answered 4 hours ago

Rob JeffriesRob Jeffries

70.3k7142243

answered 4 hours ago

Rob JeffriesRob Jeffries

70.3k7142243