june 3-7 2003corot week 4 belgian asteroseismology group a hare and hound in a bag… why are they...

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June 3-7 2003 Corot Week 4 Belgia n Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ? Cephei Stars

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Page 1: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

A Hare and Hound in a Bag…

Why are they seismologically interesting ?

Cephei Stars

Page 2: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 3: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Structure of Cephei Stars

Simple structure : no convective envelope

Massive stars : M ~ 9 – 12 M

Solar metallicity : if Z < Z too few excited modes

Convective core : mc 0.20

« Middle» main sequence stars : Xc 0.3 , c/ 150

Parameters : M,X,Z,ov,c/

Page 4: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Oscillations of Cephei Stars

f, g- and p-modes but…

low degree l and low order n excited modes

Sparse structure spectrum

Excitation : mechanism in the Fe opacity bump at ~ 2 105 K

Avoided crossings : • frequencies parameter dependent• rare enough to take it easy…

Page 5: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

BAG ground-based observations

16 Lac 3 frequencies to appear in A&A – see Bag poster 1

HD129929 5 frequencies Science Express, May 29, 2003 M,Z,ov,rotation law – see Bag poster 2

Eri ? frequencies work in progress

Page 6: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

BAG Hare & Hound Exercise KU-Leuven Ulg ROB

Site 1 : - Compute model HH1 and frequencies - Find Model HH2

Light curve

Site 2 : - Compute model HH2 and frequencies - Find Model HH1

Page 7: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Time Sampling- Total time span: 150 days- Orbital period: 6092 s (= 1h42m)- Exposure time: 0.8 s- CCD frame transfer time: 0.2 s- Rebinning in time domain: 1 data point every 32 s- Data loss due to moon: none (if launch before 2007)- Data loss due to SAA: 6-8 orbits/day pass through SAA no data loss for seismo channel, but increased noise level- Data loss due to solar panel rotation + flat field calibration: 1 orbit per 10 days- Data loss due to SEUs: 0.15 % of (rebinned) dataset- Data loss due to eclipse entries/exits: 20 s per orbit- Data loss due to technical failures: the longer the more rare, longest: +/- 6 days, about once a year- Barycentric time correction applied

Page 8: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 9: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 10: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 11: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 12: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Mode Identification

Five high amplitude peaks l = 0,1,2

One isolated peak at f2 = 82.963 Hz l = 0 One quintuplet containing f3 and f5

f3 = 80.013 Hz is l = 2, m = 0

One quintuplet containing f4

f4 = 43.704 Hz is l = 2, m = 0

Page 13: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Method Given : the error box in [log Te, log g] diagram log Te = [4.34,4.36] log g = [3.70,3.90]

On each sequence of evolution, i.e. for each (M,ov,Z,X), find the model which fits f2 fixes the age of the model

Among these, find models which also fit f3 and f4

Constraints on M,ov,Z,X

Finally, check that all peaks in the spectrum can be explained by unstable modes

Page 14: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 15: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 16: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 17: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 18: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 19: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 20: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 21: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Conclusions Frequencies given at a precision of 2 x 10–4

Error bars on parameters More precision on frequencies smaller errors bars Frequency analysis output frequencies identical to input frequencies except where crowded Even there, most frequencies are recovered exactly down to very low amplitudes Modes of high degree (example shown : l = 5) discriminate between several solutions if in a crowded region NOT detectable with ground-based telescopes

COROT

Page 22: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

BAG HH1-Frequency analysis31 frequencies

Page 23: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

BAG HH1-Mode identification

l=0l=1 l=2

5 or more multiplets

Page 24: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

HH1 - Seismic analysis

Page 25: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 26: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 27: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 28: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Page 29: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Conclusions

Ground-based observations : l = 0,1,2

Observations from space : l >>>

More frequencies more constraints on stellar parameters

COROT should observe B stars

Page 30: June 3-7 2003Corot Week 4 Belgian Asteroseismology Group A Hare and Hound in a Bag… Why are they seismologically interesting ?  Cephei Stars

June 3-7 2003 Corot Week 4 Belgian Asteroseismology Group

Screenplay : Belgian Asteroseismology Group

Starring : Aerts Conny – KU-LeuvenAusseloos Mario – UlgBarban Caroline – KU-LeuvenBriquet Maryline – KU-LeuvenBourge Pierre-Olivier – UlgCuypers Jan – ROBDaszynska Jadwiga – KU-LeuvenDe Cat Peter – KU-LeuvenDe Ridder Joris – KU-LeuvenDupret Marc-Antoine – UlgMontalban Josefina – ULgNoels Arlette – UlgScuflaire Richard – UlgThoul Anne – UlgUytterhoeven Katrien – KU-Leuven