Five New Exoplanets
The Anglo-Australian
Planet Search
Paul Butler Chris Tinney
Hugh Jones Geoff Marcy
Chris McCarthy Alan Penny Brad Carter
Photo Credit: David A. Hardy, astroart.org (c) PPARC
• Statistically useful
stellar sample
(~300 stars)
• Find all
detectable
planets out to
Jupiter-like orbits
• Do this by
achieving 2m/s
velocity
precisions over 12
year period
• Survey from Jan
1998 to >2010 to
observe
complete orbit
for planets with
Jovian period
~12yr
The AAPS
Residuals to
Orbital Fit
Stable stars
(no planet)
HD27442b (ε Ret): An Earth-like orbit
HD 27442
P = 419.0 day
K = 32.3 ms−1
e = 0.06
Mass = 1.18 MJUP /sin i
Velocity (ms−1)
40
• First circular orbit
beyond 0.3AU
– e = 0.02
– a = 1.1 au
20
0
−20
−40
RMS = 3.07 ms−1
1998.0
1999.0
2000.0
Time (Years)
2001.0
HD70642b: The best Jupiter / Solar
System analogue
AAPS
• Distant, near-circular
orbit, no hot Jupiter
– e = 0.1
– a = 3.3 au
• Some comparisons:
– Msini ~ 2 x Jupiter
– a ~ 0.6 x Jupiter
– e ~ 2 x Jupiter
[Fe/H]=+0.18
G6V
G2V
[Fe/H]=+0.04
Three Saturnmass planets
G2V
[Fe/H]=-0.06
Two Multiples
HD160691 b, c
G3IV-V [Fe/h]=+0.26
b: 645d, e=0.20, 1.7Mjup
c: 8.2yr, e=0.57, 3.1Mjup
HD154857 b, c
G5V [Fe/H]=-0.23
b: 398d, e=0.51, 1.8Mjup
c: >2yr, 14m/s/yr
Neptunes & super-Earths The New Frontier
•
Gl436
(Keck)
2.6 day period
K=18m/s
0.028au=14R*
Msini=21Mearth
•
•
55 Cnc
(HET / Lick)
2.8day period
K~8m/s
Msini=14Mearth
Is the fourth
planet found
in this system!
Neptunes & super-Earths the new frontier
2
•
•
•
9dy period. K=4m/s. p-modes=2m/s
AAPS - 4.7m/s from 200s integration
!""#$%&'$#&'(#$)*+)*+
et al.: The first 14 earth-mass exoplanet
HARPS - 0.4m/s fromN.C.
1nSantos
integration
... almost exactly 200s x (4.7/0.4)2 !
Fig. 2. Phase-folded radial-velocity measurements of Ara after subtraction of the linear trend shown in the upper panel of Fig. 1. In both
panels the error bars represent the rms around the weighted average of
the individual measurements for a given night.
The Important Questions
•
Where are the Solar System Analogs? How common
are they? How big must ELTs be to see solar
systems?
•
•
•
Extend our precisions to 12 years for 100s of stars.
How small can we find planets?
•
Hit hard on bright stars to cancel p-mode
oscillations and reach <1m/s.
•
M- & L-dwarfs in IR (GHRNIRS,CRIRES,NAHUAL)
What are the properties of multiple planet systems?
•
Hit hard on all the systems known to have planets.
The Important Answer!
• AAPS - it does all this critical science with a small
telescope on a moderate site at low cost.
• www.aao.gov.au/local/www/cgt/planet