J/ApJ/812/40 Adiabatic mass loss in binary stars. II. (Ge+, 2015)
Adiabatic mass loss in binary stars.
II. From zero-age main sequence to the base of the giant branch.
Ge H., Webbink R.F., Chen X., Han Z.
<Astrophys. J., 812, 40 (2015)>
=2015ApJ...812...40G 2015ApJ...812...40G (SIMBAD/NED BibCode)
ADC_Keywords: Models, evolutionary ; Stars, double and multiple ; Stars, masses
Keywords: binaries: close; stars: evolution; stars: interiors; stars: mass-loss
Abstract:
In the limit of extremely rapid mass transfer, the response of a donor
star in an interacting binary becomes asymptotically one of adiabatic
expansion. We survey here adiabatic mass loss from Population I stars
(Z=0.02) of mass 0.10M☉-100M☉ from the zero-age main
sequence to the base of the giant branch, or to central hydrogen
exhaustion for lower main sequence stars. The logarithmic derivatives
of radius with respect to mass along adiabatic mass-loss sequences
translate into critical mass ratios for runaway (dynamical timescale)
mass transfer, evaluated here under the assumption of conservative
mass transfer. For intermediate- and high-mass stars, dynamical mass
transfer is preceded by an extended phase of thermal timescale mass
transfer as the star is stripped of most of its envelope mass. The
critical mass ratio qad (throughout this paper, we follow the
convention of defining the binary mass ratio as
q≡Mdonor/Maccretor) above which this delayed dynamical
instability occurs increases with advancing evolutionary age of the
donor star, by ever-increasing factors for more massive donors. Most
intermediate- or high-mass binaries with nondegenerate accretors
probably evolve into contact before manifesting this instability. As
they approach the base of the giant branch, however, and begin
developing a convective envelope, qad plummets dramatically among
intermediate-mass stars, to values of order unity, and a prompt
dynamical instability occurs. Among low-mass stars, the prompt
instability prevails throughout main sequence evolution, with qad
declining with decreasing mass, and asymptotically approaching
qad=2/3, appropriate to a classical isentropic n=3/2 polytrope. Our
calculated qad values agree well with the behavior of time-dependent
models by Chen & Han (2003MNRAS.341..662C 2003MNRAS.341..662C) of intermediate-mass stars
initiating mass transfer in the Hertzsprung gap. Application of our
results to cataclysmic variables, as systems that must be stable
against rapid mass transfer, nicely circumscribes the range in qad
as a function of the orbital period in which they are found. These
results are intended to advance the verisimilitude of population
synthesis models of close binary evolution.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 86 680 Interior properties of initial models
table2.dat 81 680 Global properties of initial models
table3.dat 106 680 Thresholds for conservative dynamical
time scale mass transfer
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See also:
J/A+A/507/929 : Light curves of SDSS J100658.40+233724.4 (Southworth+, 2009)
J/MNRAS/387/1563 : Radial velocity curves of AE Aqr (Echevarria+, 2008)
J/A+A/487/1129 : Evolutionary models of binaries (Van Rensbergen+, 2008)
J/A+A/455/247 : Grid of binaries experiencing mass exchange (Tian+, 2006)
J/MNRAS/361/1091 : U Gem spectroscopy (Naylor+, 2005)
J/MNRAS/319/215 : Binary evolution (Han+, 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 F8.4 Msun Mass [0.1/100] Model mass
10- 11 I2 --- k [1/31] Mass loss sequence number
13- 24 E12.6 yr t Age (1)
26- 32 F7.4 Msun Mce [0/13.3] Convective envelope mass (2)
34- 40 F7.4 Msun Mc [0/81.3] Core mass (3)
42- 48 F7.4 Msun Mic [0/7] Inner core mass (4)
50- 56 F7.3 --- psic [-8/6] Central electron chemical potential (5)
58- 62 F5.3 [g/cm3] logrhoc [0.1/4.5] Log central density
64- 68 F5.3 [K] logTc [6.6/8.3] Log central temperature
70- 74 F5.3 --- Xc [0/0.8] Central hydrogen abundance (6)
76- 80 F5.3 --- Yc [0.2/1] Central helium abundance (6)
82- 86 F5.3 --- Xs [0.2/0.7] Surface hydrogen abundance (6)
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Note (1): Measured from the zero-age main sequence model
(excluding pre-main-sequence evolution).
Note (2): This refers to the mass depth of the base of the outermost
convection zone.
Note (3): This refers to the mass coordinate at which the helium abundance is
halfway between the surface helium abundance and the maximum helium
abundance in the stellar interior.
Note (4): the mass coordinate at which the helium abundance is halfway between
the maximum helium abundance in the stellar interior and the minimum
helium abundance interior to that maximum; in the absence of
measurable helium depletion in the hydrogen-exhaused core, Mic is
set to a default value of zero.
Note (5): Divided by kTc. Measures the degree of electron degeneracy (psic>0).
Note (6): Fraction by mass.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.4 Msun Mass [0.1/100] Model mass
10- 11 I2 --- k [1/31] Mass loss sequence number
13- 19 F7.4 [Rsun] logRad [-0.9/3.5] Log radius
21- 26 F6.4 [K] logTeff [3.4/4.7] Log effective temperature
28- 34 F7.4 [Lsun] logL [-3.1/6.4] Log stellar luminosity
36- 42 F7.3 [Lsun] logLH [-3.1/6.5] Log hydrogen-burning luminosity
44- 50 F7.3 [Lsun] logLHe [-39/5.7]?=-99 Log helium-burning luminosity (1)
52- 58 F7.3 [Lsun] logLZ [-43.1/-24.6]?=-99 Log heavy-element burning
luminosity (1)
60- 65 F6.3 [Lsun] logLnu [-4.8/5.3] Log neutrino luminosity
66 A1 --- f_logLnu [*] Flag on logLnu (2)
68- 73 F6.3 [Lsun] logLth [-7.1/5.8] Log gravothermal luminosity
74 A1 --- f_logLth [*] Flag on logLth (2)
76- 81 F6.4 --- I/MR2 [0.0002/0.3] Dimensionless moment of inertia
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Note (1): Negligibly small quantities are encoded -99.000.
Note (2):
* = Indicates a negative contribution to the net stellar luminosity
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 8 F8.4 Msun Mass [0.1/100] Initial mass model
10- 11 I2 --- k [1/31] Mass loss sequence number
13- 19 F7.4 [Rsun] logRad [-0.9/3.5] Log initial radius (1)
21- 27 F7.4 Msun MKH [0.09/81.4] Mass threshold (2)
29- 35 F7.4 [Rsun] logRKH [-0.9/2.5] Log Roche lobe radius (2)
37- 43 F7.4 [Rsun] logR*KH [-0.9/3] Log stellar radius (2)
45- 51 F7.3 --- zetaad [-2.9/69.4] Critical mass-radius exponent
for dynamical time scale mass transfer (1)
53- 59 F7.3 --- qad [-0.4/34.1] Critical mass ratio for dynamical
time scale (conservative) mass transfer (1)
61- 66 F6.4 [-] Dexp [0.0001/1] Log superadiabatic expansion
factor (3)
68- 74 F7.4 Msun MKHic [0.09/80.7] Mass threshold (4)
76- 82 F7.4 [Rsun] logRKHic [-0.9/2.4] Log Roche lobe radius (4)
84- 90 F7.4 [Rsun] logR*KHic [-0.9/2.9] Log stellar radius (4)
92- 98 F7.3 --- zetaadic [-0.4/203.5] Critical mass-radius exponent
for dynamical time scale mass transfer (3)
100-106 F7.3 --- qadic [0.6/99.7] Critical mass ratio for dynamical
time scale (conservative) mass transfer (3)
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Note (1): For models with standard mixing-length convective envelopes.
Note (2): For models with standard mixing-length convective envelopes
at which Mdot=-Mi/τKH where Mi is the initial mass.
Note (3): For models with artificially isentropic convective envelopes.
Note (4): For models with artificially isentropic convective envelopes
at which Mdot=-Mi/τKH where Mi is the initial mass.
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History:
From electronic version of the journal
References:
Ge et al. Paper I. 2010ApJ...717..724G 2010ApJ...717..724G
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 02-Feb-2016