2011A&A...533A..53M


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.27CET12:18:52

2011A&A...533A..53M - Astronomy and Astrophysics, volume 533A, 53-53 (2011/9-1)

Multidimensional hydrodynamic simulations of the hydrogen injection flash.

MOCAK M., SIESS L. and MUELLER E.

Abstract (from CDS):

The injection of hydrogen into the convection shell powered by helium burning during the core helium flash is commonly encountered during the evolution of metal-free and extremely metal-poor low-mass stars. Multidimensional hydrodynamic simulations indicate that the hydrogen injection may also occur in more metal-rich stars due to turbulent entrainment that accelerates the growth of the shell convection zone and increases its size. However, one-dimensional stellar models cast doubts that helium-flash hydrogen mixing does occur as it requires the crossing of an entropy barrier at the helium-hydrogen interface. With specifically designed multidimensional hydrodynamic simulations, we aim to prove that an entropy barrier is no obstacle to the growth of the helium-burning shell convection zone in the helium core of a metal-rich Population I star, i.e.convection can penetrate into the hydrogen-rich layers for these stars, too. We study whether this is also possible in one-dimensional stellar evolutionary calculations. We artificially shift the hydrogen-rich layer closer to the outer edge of the helium-burning shell convection zone in a Population I star with a mass of 1.25M, and simulate the subsequent evolution in two and three dimensions, respectively. We also perform stellar evolutionary calculations of the core helium flash in metal-rich stars implementing turbulent entrainment by means of a simple prescription. These simulations were performed with the Eulerian hydrodynamical code HERAKLES and the stellar evolution code STAREVOL, respectively. Our hydrodynamical simulations show that the helium-burning shell convection zone in the helium core moves across the entropy barrier and reaches the hydrogen-rich layers. This leads to a mixing of protons into the hotter layers of the core and to a rapid increase in the nuclear energy production at the upper edge of the helium-burning convection shell - the hydrogen injection flash. As a result, a second convection zone appears in the hydrogen-rich layers. In contrast to one-dimensional models, the entropy barrier separating the two convective shells from each other is largely permeable to chemical transport when allowing for multidimensional flow and consequently hydrogen is continuously mixed deep into the helium core. We find it difficult to replicate this behavior using one-dimensional stellar evolutionary calculations.

Abstract Copyright:

Journal keyword(s): stars: evolution - hydrodynamics - convection

Simbad objects: 1

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Number of rows : 1

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 V* V4334 Sgr NL* 17 52 32.69 -17 41 08.0   12.01       F2Ia 336 0

    Equat.    Gal    SGal    Ecl

C.D.S. - SIMBAD4 rel 1.7 - 2021.01.27CET12:18:52

Available data : Basic data  •  Identifiers  •  Plot & images  •  Bibliography  •  Measurements  •  External archives  •  Notes  •  Annotations


Basic data :
V* V4334 Sgr -- Nova-like Star
Origin of the objects types :

(Ref) Object type as listed in the reference "Ref"
(acronym) Object type linked to the acronym according to the original reference
() Anterior to 2007, before we can link the objet type to a reference, or given by the CDS team in some particular cases

Other object types:
NL* (), PN (DPV,PK,...), V* (V*,AAVSO), * (GSC2,[KK98b]), pA* (2007A&A), IR (2MASS)
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
ICRS coord. (ep=J2000) :
17 52 32.69 -17 41 08.0 (Infrared) [ 60 60 90 ] C 2003yCat.2246....0C
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
FK4 coord. (ep=B1950 eq=1950) :
17 49 37.63 -17 40 29.0 [ 60 60 90 ]
Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
  • ra dec : right ascension and declination (unit and frame defined according to your Output Options)
    Grey values are increasing the original precision due to the computation of frame transformations
  • (wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
  • [error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
    position angle (in degrees North celestial pole to East)
  • quality : flag of quality
    • E ≥ 10"
    • D : 1-10" (and some old data)
    • C : 0.1-1"
    • B : 0.01-0.1" + 2MASS, Tyc
    • A : VLBI, Hipparcos
  • bibcode : bibcode of the coordinates reference
Gal coord. (ep=J2000) :
010.47947 +04.41478 [ 60 60 90 ]
Spectral type is made of 3 parts: %coding is composed of 4 parts :
  • the spectral type, which is made of a temperature class, eventually a luminosity class (roman number) and/or spectral peculiarities;
  • a quality letter: A=best quality→E=worst quality, {� } =unknown quality %
  • a quality letter: A=best quality -> E=worst quality, {� } =unknown quality
  • bibcode : bibcode of the spectral type reference
Spectral type:
F2Ia C 1997BSAO...44....5K
Syntax of fluxes (or magnitudes) is : "filter-name (System) flux-value [error] quality MultVarFlags bibcode"
  • filter-name : U, B, V, R, I, G, J, H, K, u, g, r, i, z
  • (System) : may be AB (default is Vega)
  • flux-value : value of flux or magnitude
  • [error] : error value
  • quality : flag of quality of the flux value ( A=best quality -> E=worst quality, {� } =unknown quality)
  • MultVarFlags : Mult is zero or one char (J) for joined photometry ; Var can be zero or two chars (V[0-4])
  • bibcode : bibcode of the flux reference
Fluxes (4) :
B 12.01 [~] E ~
J 11.555 [0.022] C 2003yCat.2246....0C
H 8.693 [0.033] C 2003yCat.2246....0C
K 6.372 [0.018] C 2003yCat.2246....0C
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The link on the acronym of the identifiers give access to the information for this acronym in the dictionary of nomenclature.
Identifiers (12) :
An access of full data is available using the icon Vizier near the identifier of the catalogue

NAME Novalike Var in Sgr 2MASS J17523269-1741080 NAME Sakurai Object V* V4334 Sgr
DPV 1 NAME Sakurai's Object PK 010+04 2 [KK98b] 1
GSC2 S2202011182877 NAME Sakurai's Var. PN G010.4+04.4 AAVSO 1746-17

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References (336 between 1850 and 2021) (Total 336)
Simbad bibliographic survey began in 1850 for stars (at least bright stars) and in 1983 for all other objects (outside the solar system).
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Observing logs


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External archives :

Data at NED - NASA/IPAC Extragalactic Database : V* V4334 Sgr

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2MASS J17523269-1741080 PN G010.4+04.4 V* V4334 Sgr

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2021.01.27-12:18:52

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