Transcript Semin2012.2 - Institute of Astronomy

Rotational periods of the
components in Symbiotic Binary
Stars
Radoslav K. Zamanov
Institute of Astronomy, Bulgarian Academy of Sciences
in collaboration with
M.F. Bode (Liverpool, UK),
C.H.F. Melo (ESO, Chile)
A. Gomboc (Ljubliana, Slovenia),
R. Bachev, I. K. Stateva, R.Konstantinova-Antova (Sofia, Bulgaria)
03'2012
Symbiotic binary star = Red Giant + White Dwarf
Symbiotic stars are interacting binaries consisting of red giant
transferring mass onto a white dwarf.
We are investigating the projected rotational velocities of the
mass donors. Our aims are:
•
•
•
To check theoretical prediction that the red giants in these
binaries are co-rotating (for objects with known periods).
To perform comparative analysis and to check if they are
faster rotators (comparing with isolated giants and those in
wide binary systems).
To give clues for binary periods, individual mass loss rates,
select candidates for X-ray observations.
Observations:
40 symbiotic stars have been observed with the 2.2m telescope
(ESO, La Silla) + FEROS spectrograph at resolution 50000.
Our sample:
 All objects from the Symbiotic star catalogue with
0h<R.A.<24h, Declination < 00, and brighter than V< 12.5
mag.
 From literature -12 northern symbiotics.
 Our sample is flux limited, there should be no biases in
rotation.
ESO – La Silla
Altitude H=2340 m
ESO La Silla - 2.2 m telescope
OPTICON gives possibility of the Bulgarian
astronomers to use the ESO facilities !!!
Observations:
the 2.2m telescope + FEROS spectrograph
FEROS spectrograph
The 39 orders cover wavelengths from
3600 A up to 8900 A.
Observations:
the 2.2m telescope + FEROS spectrograph
- resolution 48000;
dispersion=0.03 A/pixel
- wavelength coverage: 6300 A in a single exposure
(3600 – 8900 AA)
- signal-to-noise ratio = 50; exposure=30 min; V=12 mag;
Comparison – 2.0m telescope Rozhen, Coude spectrograph
0.2 A/px, 200 A in one exposure, S/N=50, exposure=30 min; V=11.3
Fig. Theoretical spectrum
and spectra of a few
symbiotic in the near IR:
wavelength 8760-8850 AA
Fig. Numerical mask and
spectra of a few symbiotic in
Wavelength interval 87608850 AA.
To measure the projected rotational velocity (v sin i)
we used the CCF method and numerical template.
The width of the CCF is connected (calibrated for
FEROS) with the v sin i.
Two examples of the Cross-Correlation Function and the fitting gaussian.
Left – AS 316 – v sin i = 9.8 ± 1.5 km/s
Right – rapid rotator V417 Cen – v sin i = 75 ± 7.5 km/s
Fig. Check of our methods.
The measurements of v-sin-i
with FWHM and CCF
methods are in good
agreement.
On the basis of their infrared (IR) properties, the symbiotic
stars have been classified into stellar continuum (S)
and dusty (D or D' ) types.
IR types
S-type - stellar continuum - mass donor is K-M giant
D-type - dusty
mass donor is Mira
D'-type – dusty
mass donor is F-G giant
D' type
v sin i Vcrit
[km/s]
HD 330036
Hen 3-1591
StHa190 D'
V417 Cen
AS 201
critical
[km/s]
D'
F8III
107.0 160
67%
S,D'
K1III
23.7 144
G4III/IV 105.0 191
54%
D' G9Ib-II
75.0 105
71%
D' F9III
25.0 150
Comparison with catalogs
de Medeiros et al. (2002) rotation of Ib supergiant stars
16 supergiant stars G8-K0 Ib-II, v sin i = 1-20 km/s.
V417 Cen (G9Ib) - 75 km/s extreme case of very fast rotation.
The catalogue of rotational velocities for evolved stars (de Medeiros et al. 1999)
catalogue of rotational velocities for evolved stars
100 K1III 90% - vsini< 8 km/s, only 5% - vsini>20 km/s
Hen3-1591 23.7 km/s is in the top 5.
F8III-F9III - 5 objects – 10-35 km/s
AS 201 (25 km/s) is well within in this range.
HD330036 (107 km/s) is an extremely fast rotator.
G3,G4,G5 III-IV – 60 objects - <24 km/s
StHa190 (105 km/s) - is again an extremely fast rotator.
D’-type symbiotics are characterized by an earlier spectral type
giant (F-K) and lower dust temperatures. Rotational velocities
have been measured for five such stars (Zamanov et al. 2006).
Four of these five objects appeared to be very fast rotators,
compared with the catalogues of v sini for the corresponding
spectral types. At least three of them rotate at a substantial
fraction (≥ 0.5) of the critical velocity. Hence, in D’-type
symbiotics, the cool components rotate faster than the isolated
giants of the same spectral class (as predicted by Soker 2002).
As a result of rapid rotation, they must have larger mass loss
rate, probable enhanced in the equatorial regions. In addition, as
a result of the fast rotation, magnetic activity is expected to exist
in these giants.
The rotational period of the
red giant versus the orbit
period for 17 symbiotic stars
in our sample with known
orbital periods (all they are Stype).
The solid line represents
synchronization (Porb=Prot).
Among these 17 objects there
are 3, which deviate
considerably from co-rotation:
MWC560,
CD-43 14304
and RS Oph.
Possible reasons for non co-rotation:
MWC560
- highly eccentric orbit
CD-43 14304 - highly eccentric orbit
RS Oph
- ???.
e=0.70 (+/- 0.05)
e>0.5 ?
Fig. v sin i versus the spectral type:
symbiotic stars – red crosses,
black – single giants.
Isolated giants spectral classes K2-K5 III
(238 objects from catalogues of v sin i)
K2-K5 III giants in symbiotic stars
(7 objects, our measurements)
Results:
238 K2III-K5III stars:
v sin i = 1.0 - 6.7 km/s
The K giants in symbiotic stars:
v sin i = 4.5 - 8.9 km/s
mean v sin i =1.70 km/s)
mean v sin i =7.42 km/s)
The Koslmogorov-Smirnov test gives a probability of 10-4 (K-S statistics =0.60)
K-giant mass donors of symbiotic stars rotate faster than isolated K-giants !!!
Isolated giants spectral classes M2-M5 III
(12 objects from catalogues of v sin i)
M2-M5 III giants in symbiotic stars
(28 objects, our measurements mostly)
isolated M giants: 1.8 < v sin i < 18 km/s
M-giants in symbio 3.0 < v sin i < 52 km/s
(mean vsini=5.54 km/s)
(mean vsini=9.07 km/s)
The tests gives a probability of 0.09-0.01 that both distributions are coming from the same
parent population.
Isolated giants spectral classes M2-M5 III
(12 objects from catalogues of v sin i)
M2-M5 III giants in symbiotic stars
(28 objects, our measurements mostly)
isolated M giants: 1.8 < v sin i < 18 km/s
M-giants in symbio 3.0 < v sin i < 52 km/s
(mean vsini=5.54 km/s)
(mean vsini=9.07 km/s)
The tests gives a probability of 0.09-0.01 that both distributions are coming from the same
parent population.
Isolated giants spectral classes M2-M5 III
(12 objects from catalogues of v sin i)
M2-M5 III giants in symbiotic stars
(28 objects, our measurements mostly)
isolated M giants: 1.8 < v sin i < 18 km/s
M-giants in symbio 3.0 < v sin i < 52 km/s
(mean vsini=5.54 km/s)
(mean vsini=9.07 km/s)
The tests gives a probability of 0.09-0.01 that both distributions are coming from the same
parent population.
Results of statistical tests:
mean v sin i
K2III-K5III
field
2.2 km/s
symbiotic
9.5 km/s
Kolmogorov-Smirnov
7.10-6 (KS statistics =0.90)
M0III-M6III
4.8
9.2
4.10-7 (KS statistics =0.60)
M0III – M4III
M0III – M3III
M4III-M6III
1.10-9 (KS statistics =0.64)
2.10-5 (KS statistics =0.83)
0.1 (KS statistics =0.44)
Mean
v sin i
mean v sin i
M0III-M6III
M0-M1 III
M1.5-M2 III
M2.5-M3 III
M3.5-M4 III
M4.5-M5 III
M5.5-M6 III
field
4.8
symbiotic
9.2
field
km/s (N)
3.7±1.9 (23)
4.8±4.1 (14)
5.5 2.0 (8)
2.2 1.0 (3)
5.5 4.0 (5)
12.1 5.1 (4)
Kolmogorov-Smirnov
4.10-7 (KS statistics =0.60)
symbiotics
km/s (N)
9.9± 2.6 (2)
8.3± 1.1±(3)
6.5 1.8 (4)
7.7 3.3 (7)
7.9 1.7 (9)
7.6 2.0 (6)
Discussion:
The reasons for faster rotation in giants in symbiotic systems could be:
- synchronization, if the time spent by the mass-losing star on the giant branch
is longer than the synchronization time. In all symbiotic systems with orbital
period Porb ≤ 100 years tidal interaction overcomes the angular momentum
loss by the wind (Soker 2002).
- accretion during the MS phase of the present red giant: the more massive star
in the system, the present WD, had transferred material at the stage when it
had been red giant.
- backflowing material: hot component prevents part of the mass blown by the
giant from acquiring the escape velocity for the binary system. This fraction of
mass may acquire angular momentum, and if it is accreted back by the giant, it
spins-up its envelope.
- angular momentum dredge-up when convective envelope approaches the core
region of the giant.
- planet engulfment during the giant phase.
CONCLUSIONS:
•
We have measured the projected rotational velocities of 40 symbiotic stars
(v sin i) by the means of CCF and FWHM.
•
Among 16 symbiotics with known orbit and rotation, there is only one (RS
Oph) which is very likely not synchronized.
•
Our results show that the mass donors in the symbiotic stars rotate faster
than isolated giants. The faster rotation is undoubted for D’-type (yellow)
symbiotics and for those harbouring K-giant as mass donor. For those with
M giant it is valid till M4III.
FUTURE WORK:
To strengthen our results, more data on M-type isolated giants and more
v sin i measurements of K-type mass donors in symbiotics are desirable. We
intend to expand our sample with northern and fainter symbiotic stars.
Open questions:
1. Is there a bimodal distribution of v sin i of the isolated giants?
2. Hen 3-1674 rotates very fast v sin i = 52 km/s
M5III - R=139 Rsun, and mass 1-3 Msun, Vcrit=40-60 km/s.
What is this object? a monster? or just an error somewhere?
3. Is there a connection between the rotation of the red giant and the density of the circum
binary nebula and mass accretion rate?
What is the rotation of the white dwarfs in symbiotic stars?
What is the rotation of the white dwarfs in symbiotic stars?
MWD
[MꙨ]
RWD
[km]
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.35
1.38
14000
11480
10440
9220
8350
7660
6820
6120
5360
4660
3830
2780
2090
1400
dM TNR
[MꙨ]
1.47e-2
5.46e-3
2.80e-3
1.36e-3
7.64e-4
4.62e-4
2.55e-4
1.47e-4
7.77e-5
4.05e-5
1.68e-5
4.35e-6
1.33e-6
2.56e-7
P rot
[]
67 sec
172 sec
334 sec
10 min
17 min
27 min
45 min
71 min
116 min
190 min
6 h
15 h
32 h
4 days
Zamanov R.K., Bode M.F., Melo C.H.F., Stateva I.K., Bachev R., Gomboc A., Konstantinova-Antova R.,
Stoyanov, K. A.
Rotational velocities of the giants in symbiotic stars - III. Evidence of fast rotation in S-type symbiotics
2008 MNRAS.390..377
Zamanov R. K., Bode M. F., Melo C. H. F., Stateva I.K., Bachev R., Gomboc A., Konstantinova-Antova, R.;
Stoyanov, K. A.
Rotational velocities of the giants in symbiotic stars - III. Evidence of fast rotation in S-type symbiotics
2007 MNRAS.380.1053
Zamanov, R. K.; Bode, M. F.; Melo, C. H. F.; Porter, J.; Gomboc, A.; Konstantinova-Antova, R.
Rotational velocities of the giants in symbiotic stars - I. D'-type symbiotics
2006 MNRAS.365.1215
Zamanov, R. K.; Konstantinova-Antova, R.; Bode, M. F.; Melo, C. H. F.; Gomboc A., Bachev R.,
Rotation of the mass donors in symbiotic stars
V Bulgarian Serbian astronomical conference
Zamanov R.,
Tidal Interaction in High Mass X-ray Binaries and Symbiotic Stars
2011 BlgAJ..15...19Z
in collaboration with
N. A. Tomov (NAO Rozhen, BG),
M.F. Bode (Liverpool, UK),
C.H.F. Melo (ESO, Chile)
A. Gomboc (Ljubliana, Slovenia),
R. Bachev, I. K. Stateva,
K.A. Stoyanov, R.Konstantinova-Antova (Sofia, Bulgaria)
THE END