black dwarf stars and dark matter












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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







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    $begingroup$


    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









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      1












      1








      1





      $begingroup$


      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









      $endgroup$




      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




      astrophysics astronomy dark-matter stars wimps






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      asked 7 hours ago









      jormansandovaljormansandoval

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          1 Answer
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          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









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            Most of the dark matter needs to be non baryonic in the Big Bang model since the galaxies wouldn't have formed. If one needs to invoke "magic" to get a cosmological model to form galaxies, then model is probably broken.
            $endgroup$
            – Cinaed Simson
            2 hours ago














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          1 Answer
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          active

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          $begingroup$

          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









          $endgroup$









          • 1




            $begingroup$
            Most of the dark matter needs to be non baryonic in the Big Bang model since the galaxies wouldn't have formed. If one needs to invoke "magic" to get a cosmological model to form galaxies, then model is probably broken.
            $endgroup$
            – Cinaed Simson
            2 hours ago


















          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









          $endgroup$









          • 1




            $begingroup$
            Most of the dark matter needs to be non baryonic in the Big Bang model since the galaxies wouldn't have formed. If one needs to invoke "magic" to get a cosmological model to form galaxies, then model is probably broken.
            $endgroup$
            – Cinaed Simson
            2 hours ago
















          2












          2








          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









          $endgroup$



          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












          share|cite|improve this answer



          share|cite|improve this answer










          answered 7 hours ago









          Rob JeffriesRob Jeffries

          70.3k7142243




          70.3k7142243








          • 1




            $begingroup$
            Most of the dark matter needs to be non baryonic in the Big Bang model since the galaxies wouldn't have formed. If one needs to invoke "magic" to get a cosmological model to form galaxies, then model is probably broken.
            $endgroup$
            – Cinaed Simson
            2 hours ago
















          • 1




            $begingroup$
            Most of the dark matter needs to be non baryonic in the Big Bang model since the galaxies wouldn't have formed. If one needs to invoke "magic" to get a cosmological model to form galaxies, then model is probably broken.
            $endgroup$
            – Cinaed Simson
            2 hours ago










          1




          1




          $begingroup$
          Most of the dark matter needs to be non baryonic in the Big Bang model since the galaxies wouldn't have formed. If one needs to invoke "magic" to get a cosmological model to form galaxies, then model is probably broken.
          $endgroup$
          – Cinaed Simson
          2 hours ago






          $begingroup$
          Most of the dark matter needs to be non baryonic in the Big Bang model since the galaxies wouldn't have formed. If one needs to invoke "magic" to get a cosmological model to form galaxies, then model is probably broken.
          $endgroup$
          – Cinaed Simson
          2 hours ago




















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