Upload
evelyn-king
View
222
Download
3
Tags:
Embed Size (px)
Citation preview
1
Neptune Mass Exoplanets
Jeff Valenti
MJupiter / 19 = MNeptune = 17 MEarth
Geoff Marcy (Berkeley) Debra Fischer (Yale)
Andrew Howard (Berkeley) John Johnson (Caltech)
Howard Isaacson (Berkeley) Jason Wright (PSU)
Jay Anderson (STScI) Nikolai Piskunov (Uppsala)
2
Key Points
Core-Accretion planet formation scenario
Metal-rich stars have more Jupiter mass planets
Msini sensitivity has steadily improved
Largest Msini in a system constrains models
Measuring [Fe/H] for M dwarfs is hard
Known systems with Msini < MNep are metal poor
Core-Accretion predicts “planet desert” below MNep
Set limits on Msini of undetected planets
Extrapolating mass function to super-Earths
Radial velocities affected by “jitter”
Improving velocity precision with “grand solution”
Host
meta
llicityM
ass
functio
n
3
Core Accretion Planet Formation
Early PhaseSticking andCoagulation
Middle PhaseGravitational
Attraction
Late PhaseGas Sweeping
4
Synthetic Spectrum Fits
6223 K5770 K5277 K4744 K
Valenti & Fischer (2005, ApJ, 159, 141)
5
Metal rich stars have more Jupiter-mass planets
Core-Accretion!
6
Msini sensitivity has steadily improved
Mass ofNeptune
Lowest Massin FV (2005)[K < 30 m/s]
exoplanets.org
7
[Fe/H] of host star vs. lowest Msini in system
8
[Fe/H] of host star vs. highest Msini in system
9
G+M binaries constrain photometric [Fe/H] for M dwarfs
[Fe/H]+0.24
+0.45
+0.28+0.31
+0.21
+0.21Jupiters
Neptunes
Binaries
Johnso
n &
Apps (2
00
9, A
pJ, 6
99
, 933)
IR: Barbara Rojas-Ayala
10
Improve [Fe/H] for M dwarfs
11
Known systems with Msini < MNep are metal poor
Star Max MsinI [Fe/H]
HD 156668 4.2 +0.05
CoRot-7b 5.0 +0.05
GJ 1214 6.5 ?
HD 1461 8 +0.18
HD 97658 8.2 -0.23
GJ 176 8.3 -0.1
HD 7924 9 -0.15
HD 40307 9.1 -0.31
GJ 674 11.1 -0.3
HD 4308 15 -0.31
GJ 581 15.7 -0.2
HD 69830 18 -0.06
HD 125612 19 0.24
HD 190360 19 0.21
HD 219828 19.8 0.19
Mass ofNeptune
Mean[Fe/H]
is-0.13
Still needto evaluate sample bias
12
Current models predict a “planet desert”
Gas GiantsGas Giants
Ice GiantsIce GiantsMass ofNeptune
Snow Line
13
Set Limits on Mass of Undetected Planets
Bad Case, N=22
Good Case, N=131
14
Dete
ctio
ns
Can
did
ate
sFA
P <
0.0
5
Planets
15
Observations Disprove Current Models
16
Planetary Mass Function (P < 50 days)H
ow
ard
et a
l. (20
10, S
cien
ce, 3
30
, 6
53
)
HD 179079 – Apparent Uncertainties
Error bars = stddev(vseg-vmean)/√Nseg
M sin i = 27.5 MEarth
Radial velocities affected by “jitter”V
ale
nti e
t al. (2
009, A
pJ, 7
02, 9
89)
Analysis componentStellar component
Plenty of Constraints for Grand Solution
Radial Velocities for GJ 412a
21
Key Points
Core-Accretion planet formation scenario
Metal-rich stars have more Jupiter mass planets
Msini sensitivity has steadily improved
Largest Msini in a system constrains models
Measuring [Fe/H] for M dwarfs is hard
Known systems with Msini < MNep are metal poor
Core-Accretion predicts “planet desert” below MNep
Set limits on Msini of undetected planets
Extrapolating mass function to super-Earths
Radial velocities affected by “jitter”
Improving velocity precision with “grand solution”
Host
meta
llicityM
ass
functio
n