Extrasolar Planets Z:\exo\presentations\EGS2001_exo.ppt, 24.08.2015 10:54AM, 1 Tidal interactions of...
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Transcript of Extrasolar Planets Z:\exo\presentations\EGS2001_exo.ppt, 24.08.2015 10:54AM, 1 Tidal interactions of...
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 1
Tidal interactions of close-in extrasolar planets with their host stars
Ludmila Carone
Institut für Geophysik und Meterologie
Universität zu Köln, Cologne, Germany
5th Corot Week, 11. December 2003 in Berlin
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 2
Very close-in extrasolar planets
2,414HD 49674 G5 0,12 0,057 4,948 0 27,757 1 0,981
2,3520,9563,971 0 27,757 1HD 76700 G6 0,197 0,049
2,952HD 209458 G0 0,69 0,045 3,525 0 15,7 1,05 1,2
2,4751,0063,487 0 27,757 1,1BD -10 3166 G4 0,48 0,046
2,721OGLE-TR-58 G0 1,6 0,052 4,345 0 27,757 0,99 1,106
2,7211,1063,101 0 27,757 1OGLE-TR-10 G0 0,7 0,042
2,721OGLE-TR3 G0 0,5 0,023 1,19 0 27,757 1,000 1,106
2,7061,11,212 0 18,399 1,04OGLE-TR56 G0 1,45 0,023
Stellar radius [Ro]
Roche zone [Ro]
revolution period [days]
Orbit excentricity
Stellar rotation [days]
Stellar mass [Mo]
Stellar name
Spectral type
Planetary mass [Mj]
Semi major axis [AU]
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 3
Tides raised by the star on the planet
• Close-in extrasolar planets (a < 0.05 AU) experience extreme gravitational interaction
• ->Tidal bulge on planet
-> synchronous rotation (rotation = revolution)
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 4
Time to reach synchronous rotation
• Tides raised by the star on the planet
• -> synchronous rotation of the planet
0
322
3
3
2
p
p
p p
p p p p
n
k RM GMQ a aM M M
sinp pM M i-> depends on planetary mass and radius
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 5
Time to reach synchronous rotation all planets a < 0.20 AU
0.00 0.05 0.10 0.15 0.2010-510-410-310-210-1100101102103104105106
semi major axis [AU]
stellar rotationplanetary rotationsolar rotation by JupiterJupiter´s rotation by Sun
tim
e re
qu
ired
to
syn
chro
niz
e ro
tati
on
[G
y]
Z:exocalculationsrot_slow-down.sgr/Z14
tau Boo
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 6
Tides raised by the planet on the star
• Tidal bulge on the host star
-> increase/decrease of semi major axis
-> decrease/increase of stellar rotation
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 7
Tidal evolution
• Tides raised by the planet on the star decrease/increase of
semi major axis
Spin-up/decrease of star rotation
depends on planetary mass and star radius
213 13
5* P 2* * * 0
* *
13 3 k Ma(t) sign( n) R GM t a
2 Q M
113 13
* P 5* P2* *0 0 * * * 0
* * *
GM M 13 3 k M(t) a sign( n) R GM a
2 C 2 Q M
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 8
The parameters k* and Q*
• Evolution time scale depends strongly on stellar love number k* and the stellar tidal dissipation factor Q*
6 7*
*
10 Q 3 10
0.02 k 0.17
6 9*
*
Q5 10 1.5 10
k
• Pätzold & Rauer (2002) favor: 8*
*
Q1 10
k
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 9
OGLE-TR-56b (an extreme planet)
• OGLE-TR-56b was discovered during the OGLE-survey (Konacki et al, 2003)
• Parameters:
P J
P J
true J
M sin i 1.45 0.23 M
R 1.23 0.16 R
a 0.0225 0.0004 AU
e 0 Inclination 81 2.2 deg
M 1.47 0.25 M
• extremly close distance to its host star & large mass -> very strong tidal interactions
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 10
OGLE-TR-56b: Evolution of semi major axis
0 1 2 3 4 5 60.01
0.015
0.02
evolution time [Gyr]
sem
i m
ajor
axi
s [A
U]
Qstar
kstar1.5 109
Qstar
kstar
Qstar
kstar108
Qstar
kstarQstar
kstar5 106
Qstar
kstar
roche limit
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 11
OGLE-TR-56b: Evolution of stellar rotation
0 1 2 3 4 55
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
evolution time [Gyr]
stel
lar
rota
tion
[da
ys]
Qstar
kstar1.5 109
Qstar
kstarQstar
kstar108
Qstar
kstar
Qstar
kstar5 106
Qstar
kstar
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 12
OGLE-TR-56b: Evolution of stellar rotation(only in convection envelope)
0 1 2 3 4 50
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
evolution time [Gyr]
stel
lar
rota
tion
[da
ys]
Qstar
kstar1.5 109
Qstar
kstarQstar
kstar108
Qstar
kstar
Qstar
kstar5 106
Qstar
kstar
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:26AM, 13
Time to reach roche limit
0.02 0.025 0.03 0.035 0.04 0.045 0.05 0.0550.1
1
10
100
1 103
1 104
1 105
1 106
semi major axis [AU]
tim
e to
rea
ch r
oche
lim
it [
Gyr
]
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:27AM, 14
Conclusion
• OGLE-TR-56b may reach the roche limit within the lifetime of its host star
• Tidal effects could lead to a considerable spin up in stellar rotation
• Even more so, when only spin-up in convection envelope is considered (no friction between core and envelope)
• The strength of tidal effects depends strongly on the planet‘s mass and the semi major axis
• But for a better prediction the geophyisical properties Q* and k* have to be determined -> we need more data
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:27AM, 15
Very close-in extrasolar planets
2,414HD 49674 G5 0,12 0,057 4,948 0 27,757 1 0,981
2,3520,9563,971 0 27,757 1HD 76700 G6 0,197 0,049
2,952HD 209458 G0 0,69 0,045 3,525 0 15,7 1,05 1,2
2,4751,0063,487 0 27,757 1,1BD -10 3166 G4 0,48 0,046
2,721OGLE-TR-58 G0 1,6 0,052 4,345 0 27,757 0,99 1,106
2,7211,1063,101 0 27,757 1OGLE-TR-10 G0 0,7 0,042
2,721OGLE-TR3 G0 0,5 0,023 1,19 0 27,757 1,000 1,106
2,7061,11,212 0 18,399 1,04OGLE-TR56 G0 1,45 0,023
Stellar radius [Ro]
Roche zone [Ro]
revolution period [days]
Orbit excentricity
Stellar rotation [days]
Stellar mass [Mo]
Stellar name
Spectral type
Planetary mass [Mj]
Semi major axis [AU]
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:27AM, 16
OGLE-TR-3b: Evolution of semi major axis
0 1 2 3 4 5 60.012
0.014
0.016
0.018
0.02
0.022
0.024
evolution time [Gyr]
sem
i m
ajor
axi
s [A
U]
Qstar
kstar1.5 109
Qstar
kstar
Qstar
kstar108
Qstar
kstar
Qstar
kstar5 106
Qstar
kstar
roche limit
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:27AM, 17
OGLE-TR-3b: Evolution of stellar rotation
0 1 2 3 4 5 618
20
22
24
26
28
evolution time [Gyr]
stel
lar
rota
tion
tim
e [d
ays]
Qstar
kstar1.5 109
Qstar
kstar
Qstar
kstar108
Qstar
kstar
Qstar
kstar5 106
Qstar
kstar
Extrasolar Planets
Z:\exo\presentations\EGS2001_exo.ppt, 19.04.23 07:27AM, 18
OGLE-TR-3b: Evolution of stellar rotation(only in convection envelope)
0 1 2 3 4 5 65
10
15
20
25
30
evolution time [Gyr]
stel
lar
rota
tion
tim
e [d
ays]
Qstar
kstar1.5 109
Qstar
kstar
Qstar
kstar108
Qstar
kstar
Qstar
kstar5 106
Qstar
kstar