Gamow conference, Odessa , 2 0.08. 20 0 9

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Gamow conference, Odessa, 20.08.2009 Ivan L. Andronov Odessa National Maritime University Space Laboratory to Study tion in Magnetic Cataclysmic Varia Case of Exotic Newly-Discovered Po OTJ 071126+440405

description

Gamow conference, Odessa , 2 0.08. 20 0 9. Ivan L. Andronov Odessa National Maritime University. Space Laboratory to Study Accretion in Magnetic Cataclysmic Variables: The Case of Exotic Newly-Discovered Polar OTJ 071126+440405. - PowerPoint PPT Presentation

Transcript of Gamow conference, Odessa , 2 0.08. 20 0 9

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Gamow conference, Odessa, 20.08.2009

Ivan L. AndronovOdessa National Maritime University

Space Laboratory to Study Accretion in Magnetic Cataclysmic Variables: The Case of Exotic Newly-Discovered Polar

OTJ 071126+440405

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Theoretical part of the international observational campaign

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International collaboration• Inter-Longitude Astronomy (ILA):• Polar – photopolarimetric and spectroscopic study

of gravimagnetic rotators in cataclysmic variables (in Ukraine, using the CrAO telescopes)

• Superhump – study of the precession of accretion disks in nova-like and dwarf nova stars

• Stellar Bell – analysis of multi-component pulsations of short- and long- period variable stars based on own photometric observations and the data from the international databases of UAVSO (Ukraine), AFOEV (France) and VSOLJ (Japan).

• SCJ - Star classification and justification of suspected variables from surveys (space observatories: Hipparcos-Tycho and ground-based: Sky Patrol).

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General classificationGeneral classification of non-magnetic and of non-magnetic and magnetic binary starsmagnetic binary stars

• non-magnetic cataclysmic binary stars (ex-Nova, dwarf Nova, Nova-like)

• “semi-magnetic” cataclysmic binary stars (intermediate polars)

• magnetic cataclysmic binary stars (synchronizing polars)

• magnetic cataclysmic binary stars (classical polars)

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General modelGeneral model depends on depends on characteristic dimensions:characteristic dimensions:

RRwdwd – radius of the white dwarf – radius of the white dwarf

RRAA-Alfven Radius (magnetosphere)-Alfven Radius (magnetosphere)

RRcc- co-rotation radius- co-rotation radius

RRdd- maximum dimension of disk- maximum dimension of disk

RRLL – distance to the inner Lagrangian – distance to the inner Lagrangian

pointpoint

a a – orbital separation– orbital separation• Always: Rwd <Rd<RL < a, but

Rwd ~RA-”non-magnetic”

Rwd <RA~Rc <~Rd intermediate polars

Rwd <Rc < RA~ Rd<RL

asynchronous polarsRwd <Rd < Rc = RA~RL

classical polars

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Types of VariabilityTypes of Variability::

Non-Magnetic

Nova-likeDwarf Novae IP asynchr

classical

Magnetic (polars)

Characteristic timescale

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New Year 2008/2009

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New Year 2008/2009

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Theoretical modelsTheoretical models of magnetic binary starsof magnetic binary stars

• “Asymmetric propeller" – synchronization of the spin and orbital periods of the white dwarf owed to ejection of plasma by magnetic field (additional centrifugal force)

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Theoretical modelsTheoretical models : : ““Asymmetric propellerAsymmetric propeller" –" –ejectionejection

•Gravitation•Coriolis force•Centrifugal force•Viscosity•Gas pressure•Magnetic channeling

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Theoretical modelsTheoretical models of magnetic binary starsof magnetic binary stars

• “Standard model" – accretion flow channelized by the magnetic field:

• “Magnetic valve” (dependence on the accretion flux and torque on the orientation of the magnetic axis

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Ivan L. Andronov,Odessa National Maritime University;

Alexey V. Baklanov, Crimean Astrophysical Observatory

Vadim N. BurwitzMax-Planck Institut fuer Extraterrestische

Physik (Germany);

Observatori Astronomic de Mallorca (Spain)

A & A 2006

The unique magnetic cataclysmic system

V1432 Aql:Third type of Minima,Synchronization and

Capture Radius

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““Var-Comp” instrumental VR magnitudes Var-Comp” instrumental VR magnitudes choosing an optimal local constant/linear fitchoosing an optimal local constant/linear fit

HJDmin = 2451492.11112(14) + 0,140235812(12) × (Е –16347).

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““Var-Comp” instrumental VR magnitudes Var-Comp” instrumental VR magnitudes The orbital “dip” was removedThe orbital “dip” was removed

HJDHJDspinspin = = 2453223.8359(13)2453223.8359(13)++ 0.140585(30) *Е 0.140585(30) *Е (2004г.)(2004г.)

spin wide 1

spin narrow 2

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Three types of minimaThree types of minima

orbital "dips"

spin wide 1

spin narrow 2

|

1 orbital period

2 spin period

migrating minima

beat period ~60 days

4 subsequent nights from 18

Andronov, Baklanov & Burwitz (2005)

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Synchronization of the white dwarf Synchronization of the white dwarf (acceleration of the “slow” spin rotation): (acceleration of the “slow” spin rotation):

• HJDspin= 2449638.327427(74) + 0.14062831(23) *Е -7.81(11) 10-10 *Е2 (1993-2004)

• HJDspin = 2453223.8359(13)+ 0.140585(30) *Е (2004)

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Period variations:Period variations:

• TE= T0+P*Е + Q* Е2

• dP/dt=2Q/P, (dP/dt)/P=2Q/P2

• Q=-9.14.10-10 (Staubert et al. 2003 , 1.5)• Q=-6.5.10-10 (Mukai et al. 2003, 9)• Q=-7.81(11) . 10-10 (all data:1993-2004 , 61)

96.7±1.5

spin opb

spin

P P

dP

dt

Theory: AM Her (similar parameters) : 6<<260 yrs (Andronov 1982)

Observations: BY Cam (Silber et al. (1997), Mason et al. [1998]), V1500 Cyg (Pavlenko and Pelt (1988), Pavlenko and Shugarov 2005)

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Distances from the center of the white dwarf to:Distances from the center of the white dwarf to:

a – center of the secondarya – center of the secondaryRRLL – inner Lagrangian point – inner Lagrangian point

RRYY – Roche lobe in the orbital plane (“Y”) – Roche lobe in the orbital plane (“Y”)

RRHSHS – “hot spot” (Warner & Peters 1972) – “hot spot” (Warner & Peters 1972)

16R16RWDWD – minimal capture radius – minimal capture radius

RRWDWD – surface of the white dwarf – surface of the white dwarf

+

Andronov & Baklanov (Af 2007)

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Two limiting models of the accretion columns :Two limiting models of the accretion columns :1 - “vertical” (or height << radius) 1 - “vertical” (or height << radius) 2 - “inclined” (or height >> radius) 2 - “inclined” (or height >> radius)

(hope that the truth is somewhere in between): (hope that the truth is somewhere in between):

ΔφR0 / RWD

(model 1)

R0/ RWD

(model 2)

0.42 36 16

0.43 47 21

0.44 64 28

1"corridor" of

model 1

model 2

whitedwarf

dipolemagnetic field line

φ+ ψ (φ)= π(1-2Δφ)/2

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Results (briefly):Results (briefly):

• Most precise:• Orbital period• Spin period• Spin period variations + synchronization time• Beat period of 57.201d

• First (observations):• 3-rd type of minima• 2-color (VR) photometry -> color index ->

temperature

• First (theory):• Capture radius range from the phase difference

• Self-consistent values of the parameters:• Distance• Accretion rate• Capture radius• Mass/Radius of the white dwarf

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• Very new object: OTJ 0704

• Discovered on December 31, 2008/January 1, 2009• Short orbital period (117 minutes)• Deep eclipse (7minutes, from ~15 to ~19 magnitude)• Pre-eclipse: 17 minutes before• Out-of the outburst asymmetric wave• Mean brightness variations: ~15 in January, ~18 in February, Maximum at

the beginning of March• Drastic color variations ~0.6 mag!!!• Observations at 1-m Korean telescope at Mt.Lemmon (USA)• March 11-19, 2009 (Yoh-Na Joon (became a father during obs))• 1-m (Slovakia), 2.6m, 1.25m (Ukraine)

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Crimean Astrophysical Observatory: AZT-11

reduced with WinFits by L.L.Chinarova:Measuring all

S.V.Kolesnikov (reduced with MUNIpack by V.V.Breus):Faint minima missing

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BVRI photometry at the Korean Mt. Lemmon Observatory: 1m

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Crimean Astrophysical Observatory: B,I, B-I (AZT-11, K.A.Antoniuk)

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unfiltered photometry in Finland: changing states of luminosity & pre-dip shift

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unfiltered photometry in Finland: fall <5 sec

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Crimean Astrophysical Observatory: ZTSh (1 sec) – S.V.Kolesnikov, N.M.ShakhovskoyReduced with ZTShServer (V.V.Breus)Wide R filter (intensities “var/comp”)

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These studies of the magnetic cataclysmic variables were initiated in 1978 by

Prof. Vladimir P.Tsessevich

(1907-1983)

when I was a 3-rd year student and was interested in mathematical modeling of unstable Universe, black holes, gravitational lenses and pulsations

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• Need for monitoring to check dynamics of the object.• Otherwise: antigravitation maybe?

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Arto Oksanen (Finland) :3 unexpectedly different luminosity states

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Theoretical modelsTheoretical models of magnetic binary starsof magnetic binary stars

• 2D - oscillations of the orientation of the magnetic axis

Red dwarf

White dwarf

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Theoretical modelsTheoretical models of magnetic binary starsof magnetic binary stars

• 3D - oscillations of the orientation of the magnetic axis

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Theoretical modelsTheoretical models of of magnetic binary starsmagnetic binary stars

• “Swinging dipole" – excitation of the auto-oscillations of the orientation of the magnetic axis with characteristic time of ~1-10 years

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Model of Dipole+thin disk:Model of Dipole+thin disk:Dependence of the equilibrium Dependence of the equilibrium

period on the orientation period on the orientation (Andronov 2005)(Andronov 2005)

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SpinSpin phase variability phase variabilityas function of the as function of the orbitalorbital phase phase

+correlated irregular shifts:+correlated irregular shifts:clues for determinationclues for determination

of the column orientation of the column orientation

Kim, Andronov et al. (2005)

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• Angular characteristics of the Roche lobe (Andronov, 1992)• Improved expressions presented• In the poster: Andronov & Breus, this conf.

-0.1

0

0.1

0.2

0.3

0.4

0.5

0 0.2 0.4 0.6 0.8 1

mu

alp

ha

Ряд1

Ряд2

Полиномиальный(Ряд1)

i-phi

0.8

0.85

0.9

0.95

1

1.05

1.1

1.15

0 10 20 30 40

90-i

cos^

2(p

hi)

Ряд1

Ряд2

Ряд3

Ряд4

Ряд5

Ряд6

Ряд7

Ряд8

Ряд9

Ряд10

Ряд11

Ряд12

Ряд13

Ряд14

Ряд15

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

-40 10 60 110 160 210 260 310 360

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Dependence of the eclipse duration (in degrees) on the orbital inclination for various values of the mass of the white dwarf

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Dependence of the orbital inclination on the mass of the white dwarf

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The model of the system computed assuming the mass ratio q=0.3. The red dwarf (RD) fills its Roche lobe (RL). The plasma moves from the inner Lagrangian point (LP) initially along the ballistic (collisionless) trajectory (BT) and then captured by the magnetic field of the white dwarf (WD) and then moves along the dipole line (DL). At the low state, the thread point is close to the Lagrangian point, so the self-eclipse (SE) of the accretion column is observed closer in phase to the main eclipse of the main emission region by the red dwarf (when the line of centers (LC) is closest to the line of sight). The self-eclipse at the high state (SEH) is observed at another phase, practically corresponding to the minimal angle between the line of sight an the magnetic axis.

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Monitoring of selected cataclysmic variables Monitoring of selected cataclysmic variables – – AM HerculisAM Herculis

• Statistical dependence of the phase curve and characteristics of flickering on luminosity …

• Changes of orientation of the accretion column (I.e. magnetic axis of the white dwarf) have been confirmed, which had been predicted by the “Swinging Dipole” model.

• Unprecedented flare of the red dwarf of the UV Ceti -type

•Minute-scale variability as the “Red noise”.

•Fractal behaviour of luminosity variations in unprecedentally wide range from seconds to decades

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Theoretical modelsTheoretical models of magnetic binary starsof magnetic binary stars

• Advanced models of the “Standard” accretion column :

• Non-homegeneous• Asymmetric• Inclined• “Rainbow”• “Boiling” • “Falling oscillating

spaghetti”

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"Rainbow" Accretion Column

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Self-consistent model

Orbital period 117.18331±0.00017minutesDuration of eclipse 433.3 secondsDistance to the system ~140 parsecMass of the red dwarf 0.163 MSun

Radius of the red dwarf 0.204 RSun

Mass ratio q=0.3 (assuming similarity to the magnetic system AR UMa)Mass of the white dwarf 0.543 MSun

Orbital separation 0.704 RSun=4.9*108 mDistance from the inner Lagrangian point to the white dwarf 3.04*108 mIllumination of the red dwarf ~ 1.8% emission of the white dwarfRadius of the white dwarf 0.013RSun=9.06*106mOrbital velocity 437 km/sAscending/descending branch of the eclipse of the white dwarf: expected 20 sec, observed 3 secSize of the main emission region 1300 kmOrbital inclination 79-86 (79.1o)Angle between the line of centers and the magnetic axis 50.3o

Angle between the line of centers and the accretion column’s axis in the intermediate state 38.9o

Dependence of accretion geometry on luminosity !

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33D Model:D Model: I.L.Andronov; I.L.Andronov;

animation: animation: V.V.BreusV.V.Breus

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Self-consistent mathematical model of the exotic object OTJ 071126+440405= CSS Self-consistent mathematical model of the exotic object OTJ 071126+440405= CSS 081231:071126+440405 is discussed. The system was discovered as a polar at the New year night 081231:071126+440405 is discussed. The system was discovered as a polar at the New year night

31.12.2008/01.01.2009 by D.Denisenko (VSNET Circ), and we have initiated an international campaign of 31.12.2008/01.01.2009 by D.Denisenko (VSNET Circ), and we have initiated an international campaign of photometric and polarimetric observations of this object (totally ~80 runs in Ukraine, Korea, Slovakia, photometric and polarimetric observations of this object (totally ~80 runs in Ukraine, Korea, Slovakia, Finland, USA). This work is a part of the "Inter-Longitude Astronomy" (ILA) project on monitoring of Finland, USA). This work is a part of the "Inter-Longitude Astronomy" (ILA) project on monitoring of variable stars of different classes (Andronov et al., 2003). Results of this campaign will be published variable stars of different classes (Andronov et al., 2003). Results of this campaign will be published

separately (Andronov et al., 2009). Here we present the geometrical and physical model of the system. In separately (Andronov et al., 2009). Here we present the geometrical and physical model of the system. In an addition to the usual assumption that cataclysmic variables contain a Roche-lobe filling red dwarf and an addition to the usual assumption that cataclysmic variables contain a Roche-lobe filling red dwarf and

an accreting white dwarf, we propose an interpretation of three types of the brightness minima, as the an accreting white dwarf, we propose an interpretation of three types of the brightness minima, as the eclipses by the red dwarf, white dwarf and the accretion column itself (self-eclipse). In the low luminosity eclipses by the red dwarf, white dwarf and the accretion column itself (self-eclipse). In the low luminosity state, when the accretion rate is suggested to vanish, a "quiescence" is observed at the light curve, i.e. state, when the accretion rate is suggested to vanish, a "quiescence" is observed at the light curve, i.e. the optical flux comes from the illuminated secondary star and the non-accreting side of the white dwarf. the optical flux comes from the illuminated secondary star and the non-accreting side of the white dwarf.

When the accretion column becomes visible, the light curve exhibits a `hump" interrupted by the main When the accretion column becomes visible, the light curve exhibits a `hump" interrupted by the main eclipse by the red dwarf. In the "intermediate" luminosity state, the brightness increases at all phases, eclipse by the red dwarf. In the "intermediate" luminosity state, the brightness increases at all phases,

however, the main hump shifts to smaller phases and an additional minimum (self-eclipse) is observed. In however, the main hump shifts to smaller phases and an additional minimum (self-eclipse) is observed. In this state, the emitting accreting region becomes larger, and is not significantly eclipsed by the white this state, the emitting accreting region becomes larger, and is not significantly eclipsed by the white dwarf. The phase difference between the preliminary and main eclipses is smaller than in the high dwarf. The phase difference between the preliminary and main eclipses is smaller than in the high luminosity state, what is interpreted by the dependence of the position of the thread point, where luminosity state, what is interpreted by the dependence of the position of the thread point, where

magnetic field of the white dwarf captures the (initially ballistic) accretion stream. At the high state, the magnetic field of the white dwarf captures the (initially ballistic) accretion stream. At the high state, the thread point approaches the cross-section of the ballistic stream with the magnetic axis, whereas at the thread point approaches the cross-section of the ballistic stream with the magnetic axis, whereas at the intermediate state, the thread point may lie from 70% to 100% of the distance between the white dwarf intermediate state, the thread point may lie from 70% to 100% of the distance between the white dwarf and the inner Lagrangian point. As the ballistic trajectory nearly coincides with the magnetic field lines and the inner Lagrangian point. As the ballistic trajectory nearly coincides with the magnetic field lines

near the inner Lagrangian point, this argues for an "energetically optimal" orientation of the magnetic axis. near the inner Lagrangian point, this argues for an "energetically optimal" orientation of the magnetic axis. As the system is of ~20 mag at minimum, no spectral observations were made to determine parameters As the system is of ~20 mag at minimum, no spectral observations were made to determine parameters

of the red dwarf. From the statistical relationship, the mass of the red dwarf is estimated to be ~0.165 of the red dwarf. From the statistical relationship, the mass of the red dwarf is estimated to be ~0.165 solar masses, for the white dwarf (from eclipse duration) - from 0.5 to 1.76 solar masses. As the system solar masses, for the white dwarf (from eclipse duration) - from 0.5 to 1.76 solar masses. As the system

resembles ER UMa in some characteristics, the lower value may be assumed. The inclination of the resembles ER UMa in some characteristics, the lower value may be assumed. The inclination of the system and other physical parameters are estimated. The object is an excellent laboratory to study system and other physical parameters are estimated. The object is an excellent laboratory to study

multiple physical processes in the magnetic systems.multiple physical processes in the magnetic systems.

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Thank You !Thank You !