Arnaud Cassan ( ARI / ZAH Heidelberg ) 4th Planet Formation Workshop MPIA, 1 st March 2006 Discovery of a cool 5.5 Earth-mass planet through gravitational microlensing Arnaud Cassan Astronomisches Rechen-Institut (ARI), Zentrum für Astronomie der Universität Heidelberg (ZAH)
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Discovery of a cool 5.5 Earth-mass planet through gravitational microlensing
Discovery of a cool 5.5 Earth-mass planet through gravitational microlensing. Arnaud Cassan Astronomisches Rechen-Institut (ARI), Zentrum für Astronomie der Universität Heidelberg (ZAH). The microlensing effect. lens plane. source plane. Image. < mas. Source. Observer. u. - PowerPoint PPT Presentation
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Arnaud Cassan ( ARI / ZAH Heidelberg ) 4th Planet Formation Workshop MPIA, 1st March 2006
Discoveryof a
cool 5.5 Earth-mass planet through
gravitational microlensing
Arnaud CassanAstronomisches Rechen-Institut (ARI),Zentrum für Astronomie der Universität Heidelberg (ZAH)
Arnaud Cassan ( ARI / ZAH Heidelberg ) 4th Planet Formation Workshop MPIA, 1st March 2006
The microlensing effect
Observer
lens plane source plane
Source
< mas
Image
Arnaud Cassan ( ARI / ZAH Heidelberg ) 4th Planet Formation Workshop MPIA, 1st March 2006
4
2)(
2
2
uu
uuA
Magnification:
u
Magnification curves
Einstein ring radius:
SL
LSE DD
D
c
GM2
*4
(t-t0)/tE
The single lens case
Arnaud Cassan ( ARI / ZAH Heidelberg ) 4th Planet Formation Workshop MPIA, 1st March 2006
• Image separation :
• Einstein radius crossing time :
• Maximum amplification :
unresolved images !
Flux magnification monitoring
mas6.0
km/s200,kpc8,kpc6 :With
*
/
solE
SLSL
M
M
vDD
daysM0.2
M 30
sol
L
/
SL
LEE v
Dt
0when 1
1002 minmin
maxmax uu
AA
Arnaud Cassan ( ARI / ZAH Heidelberg ) 4th Planet Formation Workshop MPIA, 1st March 2006
Why a network of telescopes ?
• Ongoing microlensing events alerted by OGLE, MOA (EROS, MACHO)
Days
• Follow-up network : PLANET collaboration
Arnaud Cassan ( ARI / ZAH Heidelberg ) 4th Planet Formation Workshop MPIA, 1st March 2006