J/A+A/625/A87   Ultra-massive white dwarfs evolution models   (Camisassa+, 2019)
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The evolution of ultra-massive white dwarfs.
    Camisassa M.E., Althaus L.G., Corsico, A.H., De Geronimo F.C.,
    Miller Bertolami M.M., Novarino M.L., Rohrmann R.D., Wachlin F.C.,
    Garcia-Berro E.
    <Astron. Astrophys. 625, A87 (2019)>
    =2019A&A...625A..87C        (SIMBAD/NED BibCode)
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ADC_Keywords: Models, evolutionary ; Stars, white dwarf ; Stars, ages
Keywords: stars: evolution - stars: interiors - white dwarfs

Abstract:
    Ultra-massive white dwarfs are powerful tools to study various
    physical processes in the Asymptotic Giant Branch (AGB), type Ia
    supernova explosions and the theory of crystallization through white
    dwarf asteroseismology. Despite the interest in these white dwarfs,
    there are few evolutionary studies in the literature devoted to them.
    Here, we present new ultra-massive white dwarf evolutionary sequences
    that constitute an improvement over previous ones. In these new
    sequences, we take into account for the first time the process of
    phase separation expected during the crystallization stage of these
    white dwarfs, by relying on the most up-to-date phase diagram of dense
    oxygen/neon mixtures. Realistic chemical profiles resulting from the
    full computation of progenitor evolution during the semidegenerate
    carbon burning along the super-AGB phase are also considered in our
    sequences. Outer boundary conditions for our evolving models are
    provided by detailed non-gray white dwarf model atmospheres for
    hydrogen and helium composition. We assessed the impact of all these
    improvements on the evolutionary properties of ultra-massive white
    dwarfs, providing up-dated evolutionary sequences for these stars. We
    conclude that crystallization is expected to affect the majority of
    the massive white dwarfs observed with effective temperatures below
    40000K. Moreover, the calculation of the phase separation process
    induced by crystallization is necessary to accurately determine the
    cooling age and the mass-radius relation of massive white dwarfs. We
    also provide colors in the GAIA photometric bands for our H-rich white
    dwarf evolutionary sequences on the basis of new models atmospheres.
    Finally, these new white dwarf sequences provide a new theoretical
    frame to perform asteroseismological studies on the recently detected
    ultra-massive pulsating white dwarfs.

Description:
    New ultra-massive ONe white dwarf evolutionary sequences that take
    into account the process of phase separation expected during the
    crystallization stage based on phase diagram of dense oxygen/neon
    mixtures. Realistic chemical profiles resulting from the full
    computation of progenitor evolution during the semi-degenerate carbon
    burning along the super-AGB phase are also considered in our
    sequences. Outer boundary conditions for our evolving models are
    provided by detailed non-gray white dwarf model atmospheres for
    hydrogen and helium composition. Magnitudes in GAIA filters are also
    provided for our H rich white dwarf models.

File Summary:
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 FileName   Lrecl  Records  Explanations
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ReadMe         80        .  This file
110hdef.dat   192      511  Evolutionary track of our 1.10Msun H-deficient model
110hrich.dat  192      748  Evolutionary track of our 1.10Msun H-rich model
110gaia.dat   164      609  Absolute magnitudes of the evolutionary track of
                             our 1.10Msun H-rich model in GAIA filters
116hdef.dat   192      738  Evolutionary track of our 1.16Msun H-deficient model
116hrich.dat  192      756  Evolutionary track of our 1.16Msun H-rich model
116gaia.dat   164      592  Absolute magnitudes of the evolutionary track of
                             our 1.16Msun H-rich model in GAIA filters
122hdef.dat   192     1111  Evolutionary track of our 1.22Msun H-deficient model
122hrich.dat  192      717  Evolutionary track of our 1.22Msun H-rich model
122gaia.dat   164      562  Absolute magnitudes of the evolutionary track of
                             our 1.22Msun H-rich model in GAIA filters
129hdef.dat   192      698  Evolutionary track of our 1.29Msun H-deficient model
129hrich.dat  192      831  Evolutionary track of our 1.29Msun H-rich model
129gaia.dat   164      650  Absolute magnitudes of the evolutionary track of
                             our 1.29Msun H-rich model in GAIA filters
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Byte-by-byte Description of file (#): *hdef.dat *hrich.dat
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   Bytes Format Units   Label      Explanations
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   1-  9  F9.6  [Lsun]  logL       Logarithm of the surface luminosity
                                    in solar units
  11- 19  F9.6  K       logTeff    Logarithm of the effective temperature
  21- 29  F9.6  10+6K   logTc      Logarithm of the central temperature
                                    (million degree)
  31- 39  F9.6  [g/cm3] logRoc     Logarithm of the central density (CGS units)
  41- 49  F9.6  ---     Hc         Central hydrogen abundance
  51- 59  F9.6  ---     Hec        Central helium abundance
  61- 66  F6.3  %       Cons       Percentage of mass of the
                                    outer convective zone
  68- 73  F6.3  %       Conc       Percentage of mass of the
                                    inner convective zone
  75- 94 F20.15 [Myr]   log(edad)  Logarithm of the total age in million years
                                    counted from an arbitrary starting point (1)
  96-103  F8.5  Msun    M*         Stellar mass (in solar units)
 105-113  F9.5  Msun/yr dM/dt      Mass loss
 115-125  F11.7 [Lsun]  log(Lnu)   Logarithm of luminosity (in solar units) due
                                    to neutrino losses
 127-137  F11.7 [Msun]  logMHtot   ? Logarithm of the hydrogen content
                                    in solar mass
     138  A1    ---   n_logMHtot   [I] I for -Infinity
 140-150  F11.7 [cm/s2] logg       Logarithm of surface gravity (CGS units)
 152-162  F11.7 Rsun    Rad        Stellar radius in solar units
 164-177  E14.7 10-7W   LH         Energy released as latent heat during
                                    crystallization (CGS units)
 179-192  E14.7 10-7W   SepFase    Energy released by phase separation during
                                    crystallization (CGS units)
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Note (1): to obtain the white dwarf cooling time, the first value of this column
  must be considered as the starting point.
  The cooling time is defined as zero at the moment when the star reaches the
  maximum effective temperature. In order to accurately obtain the white dwarf
  cooling time, the zero point in the stellar age has to be obtained when the
  effective temperature reaches the maximum value.
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Byte-by-byte Description of file: *gaia.dat
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   Bytes Format Units   Label     Explanations
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   3- 14  E12.7 K       Teff      Logarithm of the effective temperature
  16- 29  E14.7 [Lsun]  logL      Logarithm of the surface luminosity
                                   in solar units
  31- 44  E14.7 Gyr     Age       Cooling time in Gyr (10^9^yr) (starting point
                                   at the beginning of the cooling sequence)
  46- 59  E14.7 [cm/s2] logg      Logarithm of surface gravity (CGS units)
  61- 74  E14.7 Rsun    Rad       Stellar radius in solar units
  76- 89  E14.7 mag     GMAG      Absolute Magnitude in the Gaia band G
  91-104  E14.7 mag     BPMAG     Absolute Magnitude in the Gaia band BP
 106-119  E14.7 mag     RPMAG     Absolute Magnitude in the Gaia band G
 121-134  E14.7 mag     BP-G      Color index BP-G
 136-149  E14.7 mag     G-RP      Color index G-RP
 151-164  E14.7 mag     BP-RP     Color index BP-RP
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Acknowledgements:
    Maria E. Camisassa, camisassam(at)googlemail.com

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(End) Maria Camisassa [La Plata, Argentina], Patricia Vannier [CDS]  20-Mar-2019
