Коуровка, 2013 К 80-летию со дня рождения

Мария Анатольевича Свечникова

В.М.Липунов

30 лет популяционному синтезу двойных звёзд

ОбзорМосковский государственный университет

им. М.В.Ломоносова,

ГАИШ МГУ,

Лаборатория космического мониторинга,

НИЯФ МГУ,

Лаборатория «Экстремальная Вселенная» ноб.лауреата Дж.Смута

Предыдущие обзоры автора по теме ПСДЗ

1994 The Ecology of Magnetic Rotators, IAU symposium 165 , Netherlands

1997 Population Synthesis of High Energy Transients, Joint Discussion 14 of the XXIIIrd General Assembly of the IAU, Kioto

1998 Relativistic binary stars population synthesis, Conference in honour of Professor A.G. Massevitch's 80th birthday, Moscow

2005 Population Synthesis of Highe Energy Sources, IAU Symp. No.230, Dublin

2006 Astrophysical Sources of Gravitational Waves, Marcel Grossman Symp. No 11, Berlin

Contents• History• Population Synthesis Methods Analytical approach Monte Carlo Machines

• Key points a - mass exchange

b - gravitational waves c - magnetic wind d - common envelope e - compact stars evolution f - natal kick

• Galaxy Sources • Extragalaxy Sources

• Cosmology • Future

History of the Binary Stars Population Synthesis

• Evolution and classificatin of Binary StarsPachinsky (60-s), Svechnikov (60-s), Tutukov &Yungelson (1973), Van den Huevel & J.Heise (1972)• Evolution of Compact starsShwartzman (1970), Illatrionov & Sunyaev (1974), Lipunov (1982) • Joint Evolution normal and Compact Stars Savonije, G. J.; van den Heuvel, E. P.  1977ApJ...214L Lipunov (1982) Astrophysics and Space Science, vol. 85, no. 1-2, July 1982, p. 451-457• The first population synthesis (Monte-Carlo Calculations)Kornilov & Lipunov 1983 SOVIET ASTRONOMY V.27, P. 163, 1983a, V.27,, P.334, 1983b Kornilov & Lipunov 1983 SOVIET ASTRONOMY V.28, P. 402, 1984

Common Evolution Normal and Neutron Stars

Lipunov (1982) Astrophysics and Space Science, vol. 85, no. 1-2, July 1982, p. 451-457

Savonije, G. J.; van den Heuvel, E. P. 1977 Astrophys. J., 214, L19

``Ecology'' of Gravi-Magnetic Rotators

(Neutron Stars & White Dwarfs) Lipunov 1986, Astrophysics of Neutron Stars (Book, Springer Verlag, 1991)

Universal diagramm for Magnetized Compact StarsThe observed magnetic rotators on the universal period - gravimagnetic parameter `` '' diagram: ``+'',

isolated WD (Lipunov and Nazin, 1992]); x- intermediate polars;  , * - accreting NS; . - radiopulsars. The horizontal bar shows the orbital eccentricity-induced accretion rate change in

binary pulsar PSR B1259-63. 

Evolutionary Tracks

The period-gravimagnetic parameter diagram for NS in binary systems. (a) with NS magnetic field decay  (the oblique part of the track corresponds to ``movement'' of the accreting NS along the so-called ``spin-up''  line), (b) a typical track of a NS without field decay in a massive binary system (Lipunov,Postnov,

Prokhorov 1996).

Equation of the Magnetic Compact Stars Evolution

Lipunov (1982) Astrophysics and Space Science, vol. 85, no. 1-2, July 1982, p. 451-457

Modes of the first mass transfer as defined by Webbink (1979)

The Main Goals• Explanation of the Gross Properties of Observed High Energy Source

Population• Determination of the Dark Parameters of the Binary Stellar Evolution• Prediction of the New Types of the Sources and Its Properties

Main Steps• Milky Way population (starting 1983)• Extragalactic population (starting 1986)• Cosmology population (starting 1986) Methods - Monte Carlo Simulations - Analytical method which is widely used for binary evolution studies is the calculation of

distribution functions (see, e.g. Iben and Tutukov, 1984a,b; Meurs and van den Heuvel, 1989; van den Heuvel, 1994, for general discussion). However, within the framework of this method it is very difficult to take into account numerous factors influencing stellar evolution; it is especially hard to

include even at a qualitative level the spin evolution  of magnetized compact stars.

“Simple” Evolution Scenario

Multidimensional EvolutionDФ/Dt + div (Фv) = DN/Dt

Main Point of the separation evolution

• Mass Loss

• Kick velocity

• Common Envelope Efficiency

Scenario Machine

Scenario Machine

Scenario Machine DiscriptonLipunov, Postnov & Prokhorov 1996

Review of Astrophysics and Space Physics, Ed. R.A. Sunyaev, Harwood Acad. Publ. Vol.17, p. 1,

http://xray.sai.msu.ru/~mystery/articles/review/sm_new.html

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Population Synthesis Progress

Main physical pointsa - mass exchange (Crowford, 1956, Snegko, 1965, van den Heuvel 1972, Tutukov & Yungelson1973)b - gravitational waves (Kraft, 1964; Pachinski, 1967, Tutukov & Yungelson, 1979)c - magnetic wind (Brandt, 1966, Skumanich, 1972)d - common envelope (Pachinski, 1976)e - compact stars evolution (Swartzman,1970, Lipunov 1982) f - natal kick (Ozernoy,1964; Shklovskiy,1969)

Monte Carlo Simulation Machines a+e - Kornilov & Lipunov Massive binaries 1983 a+e +f - Kornilov & Lipunov Massive binaries 1984 a+b + c+d+e - Lipunov & Postnov Low Massive Binaries 1987a +d - Dewey & Cordes Massive Binaries+PSR (e) 1987a+b+c+d+e+f - Scenario Machine Lipunov, Osminkin, Postnov, Prokhorov all mass 1988

a+b+c+d - Tutukov & Yungelson all mass 1992 a+b+c - Kolb low massive binaries 1992a - Pols and Marinus Open Yang Clusters 1994 a+b+c+d+f - Portregies Zvart & Spreeuw 1996

a+d+e+f Arzoumanian, Z.; Cordes, J. M.; Chernoff, D. Radiopulsars 1997 a+d+f Norci & Meurs 2000

a+b+c+d+f - Kolb, U., Davies, M. B., King, A., & Ritter, 2000

a+b+c+d+f - Tauris, T. M., & Savonije, G. J. van den Heuvel, E. P. J. 2000

a+d+f - Kalogera & Belczynski 2001 a+b+c+d+f - Pfahl, Rappaport, Podsiadlowski 2002

The first population synthesis Scenario Machine 0 (Monte-Carlo Calculations)

Kornilov & Lipunov 1983 SOVIET ASTRONOMY V.27, P. 163, 1983a, V.27,, P.334, 1983b Kornilov & Lipunov 1983 SOVIET ASTRONOMY V.28, P. 402, 1984

Results- Explanation of the Gross Parameters X-ray Pulsars- Prediction of the existence millisecond X-ray and Radio pulsars- Existence of the collapse anisotropy (kick ~100 km/s) and existance PSR+OB

binaries- Prediction of the BH+PSR systems

Распределение по типам релятивистских звезд вмассивных двойных системах.

Таблица из работы Корнилова и Липунова (1983)Диаграмма из работы Липунов & Прохоров (1986)

1983

Main Sequence

Giant OverflowRoche Lobe

WR Compact

E ? ? ? ? PSR 1913+16

P ? ? ? ? ?

A A0535+26 Vela X-1 Her X-1 Close to zero

?

SE No No ? No ?

SP No No ? No ?

SA No No SS433? No ?

BH ? Cyg X-1 SS433? ? ?

The discovery first Radiopulsars in Binary System with O-B stars

Johnston, S., Manchester, R.N., Lyne, A.G., et al. (1992) ApJ, 387, L37

1992 Johnston, S., Manchester, R.N., Lyne, A.G., et al

Main Sequence

Giant Roche Lobe Overflow

WR Compact

E PSRB1259-63 ? ? ? PSR 1913+16

P ? ? ? ? ?

A A0535+26 Vela X-1 Her X-1 ? ?

SE No No ? No ?

SP No No ? No ?

SA No No SS433? No ?

BH ? CygX-1 SS433? Cyg X-3?

?

Propeller + O-B and X-ray Gap Corbet, Robin H. Astrophysical Journal Letters v.457, p.L31, 1996

X-Ray Gap was predicted by Gnusareva & Lipunov, 1985

Raguzova & Lipunov, 2000

1996 Corbet & Robin first Propeller + OB

Main Sequence

Giant Roche Lobe Overflow

WR Compact

E PSRB1259-63

? ? ? PSR 1913+16

P X0331+53 ? ? ? ?

A ? Vela X-1 Her X-1 ? ?

SE No No ? No ?

SP No No ? No ?

SA No No SS433? No ?

BH ? CygX-1 SS433?

ULXs

? ?

2002 Galloway, Chakrabarty, Morgan & Remmilard Millisecond accreting Pulsars with WD donor XTEJ0929-314

Main Sequence

Giant Roche Lobe

Overflow

WR Compact

E PSRB1259-63

? ? ? PSR 1913+16

P X0331+53 ? ? ? ?

A ? Vela X-1 Her X-1 ? XTEJ0929-314

SE No No ? No ?

SP No No ? No ?

SA No No SS433? No ?

BH ? CygX-1 SS433?ULXs

? ?

2003 Burgay et al.2003 P+E

Main Sequence

Giant Roche Lobe

Overflow

WR Compact

E PSRB1259-63

? ? ? PSR 1913+16

P X0331+53 ? ? ? J07373039B ?

A ? Vela X-1 Her X-1 ? XTEJ0929-314

SE No No ? No ?

SP No No ? No ?

SA No No SS433? No ?

BH ? CygX-1 SS433?UULXs

? ?

NATAL KICK

• The formation of a NS during a supernova explosion  is usually accompanied by a catastrophic mass loss,  which in the majority of cases leads to disruption of the binary system; a young NS can thus "remember" the orbital velocity of the progenitor star of the order of a few 100 km s before the collapse (``Blaauw mechanism'',  Blaauw, 1955; Gott et al., 1970). However, the range of stellar parameters (masses, radii, orbital separations, etc.) is so wide that some of the systems must survive as binaries during the cataclysmic processes of stellar collapse (see Bhattacharia and van den Heuvel, 1991). Thus, the standard scenario of binary system evolution naturally produces diverse species of pulsars, on the one hand, and explains the velocities of radiopulsars  of about 100-200 km s measured shortly after their discovery (Manchester and Taylor, 1977), on the other hand.

• In 90-s reported new measurements of the radiopulsars' proper motion (Lyne and Lorrimer, 1994) and of young pulsar positions inside the associated supernova remnants (Frail et al., 1994) imply much higher birth velocities of 500-900 km s for pulsars than follows from the standard scenario. This revives the idea of an asymmetrical supernova  collapse which was put forward for the first time by I.S. Shklovskii (1970). Owing to an enormous energy liberated during the collapse, which is comparable to the rest-mass energy of the whole star, , a small anisotropy would be sufficient for the remnant to leave the Galaxy, , where c is the speed of light. A number of anisotropy mechanisms have been proposed: asymmetric neutrino emission  in a strong magnetic field during collapse (Chugai, 1984, Bisnovatyi-Kogan, 1993); double NS formation during core collapse (Imshennik, 1992); tidally induced asymmetric ignition of the WD during the AIC (Lipunov, 1983, Lipunov et al., 1987b) etc. However, a reliable reason for such anisotropy still remains unclear. Thus, as for the cosmological constant term, the anisotropy was released away (like a jinnee from the bottle) as a possible but not necessary thing.

Natal Kick History

Scenario Machine about Natal Kick

Lipunov, Postnov & Prokhorov 1997 MNRAS, 288, 245

Binary pulsar fractions among the total number of pulsars  as a function of the mean kick velocity for a maxwellian distribution  (left-hand panel) and that fitting Lyne and Lorimer's data (right-hand panel). The width of each curve reflects the dispersion of power index in the initial mass ratio spectrum. The number for pulsars+planets  is reduced 10 times for clarity.

Binary PulsarsWillems, B.; Kolb, U.

Monthly Notice of the Royal Astronomical Society, Volume 337, Issue 3, pp. 1004-1016. 2002

Natal KickCONFORMISM

Arzoumanian, Z.; Chernoff, D. F.; Cordes, J. M. The Astrophysical Journal, 568:289-301, 2002

Common Envelope

The Dependence of the Common Envelope Efficiency on Binary Star System Parameters

Webbink,1984Ap.J.,277, 555

! The Dependence of the Common Envelope Efficiency on Binary Star System Parameters Weiler, K.; Politano, M. 2004AAS...205.1911

WD in Low Massive Binary SystemsLipunov & Postnov,1987

Population Synthesis of X-Ray Sources at the Galactic Center

Lipunov, V. M., Ozernoy, L. M., Popov, S. B., Postnov, K. A., & Prokhorov, M. E.

Astrophysical Journal v.466, p.234,1995

On the Chandra X-Ray Sources in the Galactic Center Belczynsky & Ronald, 2004,  Astrophysical Journal, Volume 616, pp. 1159-1166.

• Recent deep Chandra surveys of the Galactic center region have revealed the existence of a faint, hard X-ray source population. While the nature of this population is unknown, it is likely that several types of stellar objects contribute. For sources involving binary systems, accreting white dwarfs and accreting neutron stars with main-sequence companions have been proposed. Among the accreting neutron star systems, previous studies have focused on stellar wind-fed sources. In this paper, we point out that binary systems in which mass transfer occurs via Roche lobe overflow (RLOF) can also contribute to this X-ray source population. A binary population synthesis study of the Galactic center region has been carried out, and it is found that evolutionary channels for neutron star formation involving the accretion-induced collapse of a massive ONeMg white dwarf, in addition to the core collapse of massive stars, can contribute to this population. The RLOF systems would appear as transients with quiescent luminosities, above 2 keV, in the range from 1031 to 1032 ergs s-1. The results reveal that RLOF systems primarily contribute to the faint X-ray source population in the Muno et al. survey and that wind-fed systems can contribute to the less sensitive Wang et al. survey. However, our results suggest that accreting neutron star systems are not likely to be the major contributor to the faint X-ray source population in the Galactic center.

A Chandra Observation of the Nearby Lenticular Galaxy NGC 5102: Where are the X-Ray Binaries?

Kraft, R. P.; Nolan, L. A.; Ponman, T. J.; Jones, C.; Raychaudhury, S. 2005, Ap. J., 625, 785 • We present results from a 34 ks Chandra ACIS-S observation

of the low-mass X-ray binary (LMXB) population and the hot interstellar medium (ISM) in the nearby (d=3.1 Mpc) lenticular galaxy NGC 5102, previously shown to have an unusually low X-ray luminosity. We detect 11 X-ray point sources within the D25 optical boundary of the galaxy (93% of the light), one-third to one-half of which are likely to be background active galactic nuclei (AGNs). One of the X-ray sources is coincident with the optical nucleus and may be a low-luminosity AGN. Only two sources with an X-ray luminosity greater than 1037 ergs s-1 in the 0.5-5.0 keV band were detected, one of which is statistically likely to be a background AGN. We expected to detect seven or five such luminous sources if the X-ray binary (XRB) population scales linearly with the B-band or J-band magnitudes, respectively, of the host galaxy. By this measure, NGC 5102 has an unusually low number of XRBs. The deficit of LMXBs is even more striking, because some of these sources may in fact be high-mass X-ray binaries (HMXBs). NGC 5102 is unusually blue for its morphological type and has undergone at least two recent bursts of star formation only ~1.5×107 and ~3×108 yr ago. We present the results of optical/UV spectral synthesis analysis and demonstrate that a significant fraction (>50%) of the stars in this galaxy are comparatively young (<<109 yr old). We discuss the relationship between the XRB population, the globular cluster (GC) population, and the relative youth of the majority of stars in this galaxy. If the lack of X-ray binaries is related to the relative youth of most of the stars, this would support models of LMXB formation and evolution that require wide binaries to shed angular momentum on a timescale of Gyr. We have also analyzed archival Hubble Space Telescope (HST) images of NGC 5102 and find that it has an unusually low specific frequency of GCs (SN~0.4). The lack of LMXBs could also be explained by the small number of GCs.

Stellar-mass black hole binaries and ultraluminous X-ray sources

• Rappaport, S. A.; Podsiadlowski, Ph.; Pfahl, E, 2005Monthly Notices of the Royal Astronomical Society, Volume 356, Issue

2, pp. 401-414

• Ultraluminous X-ray sources (ULXs) with Lx > 1039 erg s-1 have been discovered in great numbers in external galaxies with ROSAT, Chandra and XMM-Newton. The central question regarding this important class of sources is whether they represent an extension in the luminosity function of binary X-ray sources containing neutron stars and stellar-mass black holes (BHs), or a new class of objects, e.g. systems containing intermediate-mass BHs (100-1000 Msolar). We have carried out a theoretical study to test whether a large fraction of the ULXs, especially those in galaxies with recent star formation activity, can be explained with binary systems containing stellar-mass BHs. To this end, we have applied a unique set of binary evolution models for BH X-ray binaries, coupled to a binary population synthesis code, to model the ULXs observed in external galaxies. We find that for donor stars with initial masses >~10 Msolar the mass transfer driven by the normal nuclear evolution of the donor star is sufficient to potentially power most ULXs. This is the case during core hydrogen burning and, to an even more pronounced degree, while the donor star ascends the giant branch, although the latter phases last only ~5 per cent of the main-sequence phase. We show that with only a modest violation of the Eddington limit, e.g. a factor of ~10, both the numbers and properties of the majority of the ULXs can be reproduced. One of our conclusions is that if stellar-mass BH binaries account for a significant fraction of ULXs in star-forming galaxies, then the rate of formation of such systems is ~3 × 10-7 yr-1 normalized to a core-collapse supernova rate of 0.01 yr-1.

Rappaport, S. A.; Podsiadlowski, Ph.; Pfahl, E, 2005Monthly Notices of the Royal Astronomical Society, Volume

356, Issue 2, pp. 401-414

X-ray Luminosity Evolutionof the Galaxies

• The first calculation of such an evolution was performed by Tatarintzeva et al. (1989)

Evolution in Eliptical GalaxyLipunov & Postnov,1988

Binary PSR + Black Hole

Kornilov & Lipunov 1983b Sov.Astr. V.28, P. 402

Narayan & Piran, 1991,Astrophysical Journal, 379, L17 (Analytical Estimation):

BH+NS Formation Rate ~ 1/30 000 yrs(BH+PSR)/PSR ~ 1/300

Scenario Machine CalculationsBinary Pulsars with Black Hole

Lipunov, Bogomazov & Abubikerov, 2005, MNRAS, V. 359, 1517

(BH+PSR) = 1/1500

Lipunov et al.1994 Astrophysical Journal Letters v.423, p.L121(BH+PSR) = 1/1000

Black Holes Mass FunctionLipunov, Bogomazov & Abubikerov 1995b

Prediction of the Observable Number Low Massive Black Holes

Relativistic Binary Merging

• There are 3 type of merging reactions (M-reactions) of the relativistic stars: NS + NS -> GWB + GRB?+? NS + BH -> GWB + BH+GRB ?+? BH + BH -> GWB + BH • Binary relativistic stars merging - the most powerfull high energy transients in the

Universe • That is equal to Planckian luminosity (Lipunov, 1992) : After outstanding experiments:

- BepoSAX (Costa et al. 1997, IAUC 6572)- and discovery of afterglow fenomena in GRB 970228 (Groot et al. 1997, IAUC 6584; Sahu et al. 1997, IAUC 6606)- and discovery of spectral lines in GRB 970508 (z=0.835) (Metzger, Djorgovski, Stteidel, Kulkarni, Adelberger, Frail, 1997, IAUC6655) we know that in the Universe there are real sources with luminosity more than 10^ 50.

Как образуются релятивистские двойные?

Neutron Stars Merging RateStability of Results

Evolution of the Double Neutron StarMerging Rate and the Cosmological Origin of Gamma-ray Burst Sources

Temporal evolution of NS+NS (filled circles) and NS+BH (open circles) coalescence  rates calculated for           binaries and normalized to a model elliptical galaxy with baryonic mass              (Lipunov et al., 1995e, Astrophysical Journal

v.454, p.593 ).

Тёмная энергия в 1995г. Lipunov et al., 1995e, Astrophysical Journal v.454, p.593

Gravitational Waves

HANS A. BETHE, G. E. BROWN

THE ASTROPHYSICAL JOURNAL, 517:318 327, 1999 May 20Bethe, H. A., & Brown, G. E. 1998, ApJ, 506, 78 0

High Massive Black Hole (from stars>80 M solar mass collapsing due to electron-positron annihilation)

  ”In the last two sections we have addressed the evolution of massive

binaries in which the primary evolves into a high-mass black hole in an empirical way. We match rather well the population synthesis results of Lipunov et al. (1997). In particular, these authors find that introduction of kick velocities increases their merging rate by an order of magnitude.”

Our final (BH-BH) merger rate of (4-6)×10-6 yr-1 increases the Bethe & Brown (1998) rate of gravitational waves by a factor of 1.3, largely

because of the higher chirp mass with high-mass black holes.

Evolution of Supernova Explosion Rates in the Universe

• Jorgensen, H. E.; Lipunov, V. M.; Panchenko, I. E.; Postnov, K. A.; Prokhorov, M. E.

1997, Astrophysical Journal v.486, p.110

The        -    curves for all SN types for             (left-hand panel) and         (right-hand panel)

Два механизма вспышек СНIa

В двойной системе возможен отложенный (delayed)(через миллиарды лет) набор массы до Чандрасекаровского предела – либо в результате аккреции вещества со второго компаньона (SD-mechanism, Механизм Шацмана, 195…)

либо в результате слипания (merging) (DD-mechanism, Iben & Tutukov, 1984, Webbink, 1984).

Рис. 1.– Эволюция скорости взрывов сверхновых Ia в галактике с массой 1011 M после δ-образного звездообразования (Jorgensen

et al. 1997)

Функция Грина эволюции темпа сверхновых (эллиптическая галактика)

Totani, T., Morokuma, T., Oda, T. et al., Delay Time Distribuiton Measurement of Type Ia Supernovae by

Subaru/XMM-Newton Deep Survey and Implications for the Progenitor, Publ. Astron.Soc.Japan, (2008?)

Изучение сверхновых в последние годы позволило впервые говорить о наблюдаемой эволюции частоты сверхновых в эллиптических галактиках (Totani et al., 2009). Эти результаты были получены по наблюдению кандитатов в сверхновые Iа по данным in Subaru/XMM-Newton Deep Survey (SXDS). При этом возраст эллиптических галактик определялся на основании 9 band photometric from optical to mid-infrared wavelength.

Рис. 2.–Эволюция скорости взрывов сверхновых [на (100 лет)-1] после

δ-образного звездообразования для галактики, чья полная светимость в K фильтре составляет 1010 LK,

на момент, когда возраст галактики равен 11 млрд. лет (Jorgensen et al., AJ, 486,

1997). Закрашенные квадратики – наблюдательные точки (Totani et al. 2009). Незакрашенная точка получена из анализа эволюции

скорости взрывов сверхновых в близких эллиптических галактиках (Mannucci et al. 2005).

V.M. Lipunov, I.E. Panchenko, M.V. Pruzhinskaya, New Astronomy, 16, 250, 2011

Unsolved Problems

Where Are the Be/Black Hole Binaries? (last paper Zhang &  Wang  2004ApJ...603..663 )

• PSBS in Globular Clusters (see Kuranov, A. G.; Postnov, K. A. Astronomy Letters,2004, Vol. 30, Issue 3, p.140-147 )

•Short Gamma-Ray Burst – NS-NS merging (last paper Voss, & Tauris  2003MNRAS.342.1169V;

Bogomazov, Lipunov & Tutukov, 2005 (in preparation) • Long Gamma-ray Hypernova (Izzard, Robert G.; Ramirez-Ruiz, Enrico; Tout, Christopher A

2004MNRAS.348.1215I .)

•

Concluding Remarks and Future Prospects

• The future development of the method can be considered from two different points of view. • First, this is the amendment of the method itself in the sense of more adequate and detailed

description of stellar evolutionary tracks (as performed by, e.g., Pols and Marinus (1994). In fact, this is indeed necessary for some classes of objects (for instance, if we investigate in detail a particular type of object, e.g. cataclysmic variable,  their distributions over masses, orbital periods, etc.). However, here one should always bear in mind that various uncertainties of the modern evolutionary scenario (such as adequate description of the common envelope  stage, Roche lobe overflow  process, parameters of the magnetic stellar wind,  etc.), could hardly make the detailed calculations more precise than they are already (i.e. they do remain uncertain to within the same factor of 2).

• On the other hand, as the 30-years history of the Scenario Machine shows (see particularly the last few sections of this review), interesting results (and more statistically reliable) can be obtained by applying Scenario Machine methods to various examples of extragalactic binary  systems evolution. That is, it may be better to refer not to the evolution of stars, but to evolution of the baryonic component of the Universe.

• One important feature revealed by our computations is that practically all populations of stars in galaxies are very sensitive to the previous star formation history. In this connection, a more accurate account of the relevant chemical evolution is urgently needed, and this is what we are going to do in the near future.

Популяционный синтез двойных звезд: публикации

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