David Brown Andrew Collier Cameron, Leslie Hebb, Cassie Hall IAUS 276, Turin, 14/10/2010.
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Transcript of David Brown Andrew Collier Cameron, Leslie Hebb, Cassie Hall IAUS 276, Turin, 14/10/2010.
![Page 1: David Brown Andrew Collier Cameron, Leslie Hebb, Cassie Hall IAUS 276, Turin, 14/10/2010.](https://reader036.fdocuments.in/reader036/viewer/2022070308/551c0e82550346ad4f8b52b5/html5/thumbnails/1.jpg)
David BrownAndrew Collier Cameron, Leslie Hebb, Cassie Hall
IAUS 276, Turin, 14/10/2010
![Page 2: David Brown Andrew Collier Cameron, Leslie Hebb, Cassie Hall IAUS 276, Turin, 14/10/2010.](https://reader036.fdocuments.in/reader036/viewer/2022070308/551c0e82550346ad4f8b52b5/html5/thumbnails/2.jpg)
• Can we use gyrochronology to reliably estimate the ages of exoplanet systems?
• Do tidal interactions affect the natural spin down of exoplanet host stars?
• Can we constrain Q’s and Q’p through modelling tidal interactions?
Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
![Page 3: David Brown Andrew Collier Cameron, Leslie Hebb, Cassie Hall IAUS 276, Turin, 14/10/2010.](https://reader036.fdocuments.in/reader036/viewer/2022070308/551c0e82550346ad4f8b52b5/html5/thumbnails/3.jpg)
Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
• Magnetic braking caused by stellar wind
Weber & Davis (1967)
Rotation period can be used as a proxy for age.
3s
Barnes (2007)
![Page 4: David Brown Andrew Collier Cameron, Leslie Hebb, Cassie Hall IAUS 276, Turin, 14/10/2010.](https://reader036.fdocuments.in/reader036/viewer/2022070308/551c0e82550346ad4f8b52b5/html5/thumbnails/4.jpg)
Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
2,121
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![Page 5: David Brown Andrew Collier Cameron, Leslie Hebb, Cassie Hall IAUS 276, Turin, 14/10/2010.](https://reader036.fdocuments.in/reader036/viewer/2022070308/551c0e82550346ad4f8b52b5/html5/thumbnails/5.jpg)
Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
2,121
5
3
18
11
'2
81
i
ii
i
i
i
efn
efa
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M
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nefef
a
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M
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ppp 43
32
'2
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322 ~,min
'2
9
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sss n
efefa
R
M
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Q
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orb
sss
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orb
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L
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2 ~,min
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Dobbs-Dixon et al (2004)
![Page 6: David Brown Andrew Collier Cameron, Leslie Hebb, Cassie Hall IAUS 276, Turin, 14/10/2010.](https://reader036.fdocuments.in/reader036/viewer/2022070308/551c0e82550346ad4f8b52b5/html5/thumbnails/6.jpg)
Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
2,121
5
3
18
11
'2
81
i
ii
i
i
i
efn
efa
R
M
M
Q
n
e
e
nefef
a
R
M
M
Q
n pp
p
s
ppp 43
32
'2
9
243
322 ~,min
'2
9
ss
ss
s
p
sss n
efefa
R
M
M
Q
n
orb
sss
orb
pp
orb
ss
L
I
L
I
L
I
e
e
e
e
a
a2
2
2 ~,min
12
Dobbs-Dixon et al (2004)
![Page 7: David Brown Andrew Collier Cameron, Leslie Hebb, Cassie Hall IAUS 276, Turin, 14/10/2010.](https://reader036.fdocuments.in/reader036/viewer/2022070308/551c0e82550346ad4f8b52b5/html5/thumbnails/7.jpg)
Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
2,121
5
3
18
11
'2
81
i
ii
i
i
i
efn
efa
R
M
M
Q
n
e
e
nefef
a
R
M
M
Q
n pp
p
s
ppp 43
32
'2
9
243
322 ~,min
'2
9
ss
ss
s
p
sss n
efefa
R
M
M
Q
n
orb
sss
orb
pp
orb
ss
L
I
L
I
L
I
e
e
e
e
a
a2
2
2 ~,min
12
Dobbs-Dixon et al (2004)
![Page 8: David Brown Andrew Collier Cameron, Leslie Hebb, Cassie Hall IAUS 276, Turin, 14/10/2010.](https://reader036.fdocuments.in/reader036/viewer/2022070308/551c0e82550346ad4f8b52b5/html5/thumbnails/8.jpg)
Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
Integrate equations forward in time from a set of parameters at some time in the past.
Initial conditions◦ Ωp = n◦ t0 = 0.150 Gyr◦ Ωs scaled from P – (J-K) relation for Coma-
Berenices cluster (Collier Cameron et al, 2009)
Evaluation◦ At each time step, calculate fit to observed
parameters◦ Add prior on stellar age from isochrones
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Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
Star◦ Late G-dwarf◦ Teff = 5500±100 K◦ [M/H] = 0.1±0.1◦ age = 5.5+9.0-4.5 Gyr
Planet◦ Porb = 0.79 days◦ a = 0.0164±0.0005◦ e = 0.02±0.02◦ No alignment measurements to date.
Hebb et al (2010)
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Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
![Page 11: David Brown Andrew Collier Cameron, Leslie Hebb, Cassie Hall IAUS 276, Turin, 14/10/2010.](https://reader036.fdocuments.in/reader036/viewer/2022070308/551c0e82550346ad4f8b52b5/html5/thumbnails/11.jpg)
Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
![Page 12: David Brown Andrew Collier Cameron, Leslie Hebb, Cassie Hall IAUS 276, Turin, 14/10/2010.](https://reader036.fdocuments.in/reader036/viewer/2022070308/551c0e82550346ad4f8b52b5/html5/thumbnails/12.jpg)
Integration of MCMC median parameters
age ~ 3 Gyr
agegyro ~ 0.9 Gyr
Very close to Roche limit◦ tremain ~ 1 Myr
For same e0 and a0, range of Qs give compatible solutions.
Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
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Qs ~ 105 – 106
Qp ~ 104 - 109
All imply that WASP-19b is in infall.
All give very short remaining lifetimes.
Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
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Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
Star◦ F6◦ Teff = 6400±100 K◦ age = 0.630+0.950-0.530 Gyr
Planet◦ Porb = 0.94 days◦ a = 0.02026±0.00068◦ e = 0.0092±0.0028◦ Well aligned (Triaud et al 2010)
λ=5.0o +3.1-2.8
Hellier et al (2009)
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Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
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Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
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Median MCMC parameters imply WASP-18b on verge of infall.
Short remaining lifetime
Older than gyrochronology suggests.
Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
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Range of solutions give range of histories.
Qs ~ 107 – 109
age ~ 0.4 – 1.5 Gyr
agegyro~ 0.4 Gyr
tremain ~ 0.06 – 5 Gyr
Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
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Tidal interactions with hot Jupiters can have a strong effect on stellar rotation.◦ Host stars will rapidly spin up during the final stages of
infall.◦ Effect is observable.
Gyrochronology is a useful tool, but should not be trusted absolutely for hot Jupiter hosts◦ WASP-19 much older, in line with isochrones.◦ WASP-18 could be much older, but still uncertain.
Q not universal.◦ Different systems can have completely different ranges
of values.◦ Affects timescale of evolution, but not the overall
pictureAre falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010
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Barnes S. A., 2007, ApJ, 669, 1167 Collier Cameron A. et al., 2009, MNRAS, 400, 451
Dobbs-Dixon I., Lin D. N. C., Mardling R. A., 2004, ApJ, 610, 464
Eggleton P. P., 1983, ApJ, 268, 368 Hebb L. et al., 2010, ApJ, 708, 224 Hellier C. et al., 2009, Nature, 460,1098 Skumanich A., 1972, ApJ, 171, 565 Weber E. J., Davis Jr. L. 1967, ApJ, 148,
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Are falling planets spinning up their host stars? David Brown, IAUS 276, Turin, 14/10/2010