Transit Timing, Radius, Albedo, and Satellites of Extrasolar Planets with MagIC’s Upgrade
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Transcript of Transit Timing, Radius, Albedo, and Satellites of Extrasolar Planets with MagIC’s Upgrade
Transit Timing, Radius, Albedo, and Satellites of Extrasolar Planets with
MagIC’s UpgradeMercedes López-Morales
Carnegie-DTM
Extrasolar Planets to Date
•235 planets discovered to date:• 233 from Radial Velocities• 19 from Transits• 4 from Microlensing• … +4 pulsar planets
(Last update: May 10
2007) Main Future Goals•Physical characterization of known planets•Discovery of the first Earth-mass planets
TRANSITS: at present the richest source of information
• Planet-to-Star Radius Ratio• Orbital inclination and stellar limb darkening
• Planetary Albedos• Satellites around theplanets• Additional planets in those systems• Earth-mass planets
Transit Timing
from Agol et al. (2004)
Transit TimingCan detect extrasolar planets as small as 2-3
MEarth
based on eq. 1 of Holman & Murray (2005)
Transit Timing
From Seager & Mallén-Ornellas (2003)
= Rp / Rs
p = (T - F) / 2ph = light curve noise / sec
(t0) -2ph p1/2
Recent Transit Timing Attempts
Planet (t0) Transits Reference
TrES-1 ~100 sec 11 Steffen & Algol (2005)
HD189733b ~60 - 100 sec 5 Bakos et al. (2006)
OGLE-TR-113 ~12 - 71 sec 3 Gillon et al. (2006)
MagIC Upgrade
POETS: Portable Occultation,Eclipse, and Transit System.
- 512x512 pixel Frame-transfer CCD- 16 m pixels- > 90% QE up to 1 m- ≤ 6 e- readout noise- Full well ~ 200,000 e-/pixel- Three-stage Peltier cooler (-70C in air)
CCD47-20 chip from e2V technologies
- 1024x1024 pixel Frame-transfer CCD- 13 m pixels- > 70% QE between 0.4-0.8 m- ~ 2 e- readout noise- Full well ~ 100,000 e-/pixel- cooled at -120C (MagIC dewar)
POETS on Magellan Telescopes
OGLE-TR-56b on Magellan with POETS
25”
x 2
5”
FoV
OGLE-TR-56b OGLE image
60”
x 6
0”
FoV
Test Transit of OGLE-TR-56b on Magellan
- 2 sec exposure sequence in I-band- S/N = 400 per point, i.e. 2.5 mmags- Red-noise ~ 4.5 mmags
~0.43 mmags in 100 sec bins!
Performance of POETS
Observational Strategy
GOAL: 3-5 transits or more of each target per year 2-3 occultations per year
Bonus Material
• Error in Rp < 0.5% (assuming R* = 0)
• Satellites?
• Albedos - OGLE-TR-56b, 113b and 132b have P [1.0, 2.0] days - Could have Tsurf ~ 2500-3000K
- Occultations could be ~ 0.5 mmags deep
Parameter Precision Goals
Summary- The MagIC update will be able to improve light curve photometric precision on ground-based telescopes by a factor of 6.- That photometric precision improvement will allow:
- improvement on ground-based albedo detections at optical wavelengths.- improvement on detection of satellites.- improvements on planetary radius measurements- improvements on the detection of additional planets via transit timing.
- Transit timing data of particular interest for OGLE planets.
- Project fully funded by NASA Origins Program. Observations begin June 2007 with MagIC.
Project Members
Jim ElliotSara SeagerElisabeth AdamsAmanda Gulbis ……. all from MIT
David Osip (LCO, OCIW)
Mercedes López-Morales (CIW-DTM)