Title: "High efficiency coronagraphy and wavefront control schemes for direct imaging of extrasolar planets from space"

Abstract: Although more than 200 exoplanets have now been identified, direct detection (imaging) and characterization (spectroscopy) of exoplanets similar to ours remains extremely challenging. The high star to planet contrast (1e10 in the visible) and small angular separation require both a high performance coronagraph and exquisite control of the system wavefront. In the last few years, significant advances in coronagraphy and wavefront control techniques suggest that this may be achievable in the foreseeable future. I will review these recent advances and show that a visible telescope much smaller than what was previously envisioned for the Terrestrial Planet Finder Coronagraph mission could carry out a scientifically valuable imaging survey of a few tens of nearby stars, with sufficient sensitivity to detect Earth-like planets.

Date and Time: Monday, 18 Dec. 2006, 3:00pm
Location: Michelson Science Center, 770 S. Wilson Ave., Large Conference Room, 102 Morrisroe
Speaker: Dr. Victoria Meadows

Title: "Earths Around Other Stars: Simulating the Star-Planet Interaction and its Effects on Biosignatures."

Abstract: The search for life outside our Solar System will be undertaken by using remote-sensing techniques to understand the spectroscopic properties of extrasolar planets. To improve our ability to interpret what we might find, the Virtual Planetary Laboratory team is using realistic stellar spectra and generalized planetary climate-chemistry models to explore the effect of different stellar energy distributions on the atmospheric photochemistry and resultant spectra of Earth-like planets. In this presentation I will review results to date on the effects on atmospheric photochemistry, planetary habitability and the detectability of biosignatures for planetary host stars of different spectral type and UV activity levels. I will also present new results on attempts to generate "false positive" signatures of oxygen from terrestrial planets in the habitable zone, using high incident stellar UV and dense carbon dioxide atmospheres.

Past Colloquia - 2007

Date and Time: Tuesday, 16 Jan. 2007, 12:00 noon - 1:00 pm.
Location: 162 S. Mudd (corner of Wilson Ave and California Blvd), Caltech.
Speaker: Lisa Kaltenegger (Harvard-Smithsonian Center for Astrophysics)

Title: "Spectral evolution of an Earth-like planet and how to detect it"

Abstract: We have developed a characterization of the geological evolution of the Earth's atmosphere and surface in order to model the observable spectra of an Earth-like planet through its geological history from space. These calculations are designed to guide the interpretation of an observed spectrum of such a planet by future instruments that will characterize exoplanets like TPF. Our models focus on spectral features that either imply habitability or are required for habitability. These features are generated by H2O, CO2, CH4, O2, O3, N2O, and vegetation-like surface albedos. We chose six geological epochs to characterize. These epochs exhibit a wide range in abundance for these molecules, ranging from a CO2 rich early atmosphere, to a CO2/CH4-rich atmosphere around 2 billion years ago to a present-day atmosphere. We analyzed the spectra to quantify the strength of each important spectral feature in both the visible and thermal infrared spectral regions, and the resolutions required to unambiguously observe the features for each epoch. We find a wide range of spectral resolutions required for observing the different features. For example, H2O and O3 can be observed with relatively low resolution, while O2 and N2O require higher resolution. We also find that the inclusion of clouds in our models significantly affects both the strengths of all spectral features and the resolutions required to observe all these.

Date and Time: Tuesday, 30 Jan. 2007, 12:00 noon - 1:00 pm.
Location: Michelson Science Center
Speaker: Ian Dobbs-Dixon of UCO Lick will present:

Title: "Dynamical Heat Re-Distribution in Hot-Jupiters"

Abstract: Transiting planets have provided us with multiple new techniques for exploring the structures and atmospheres of extra-solar planets. New observations are revealing, among other things, spectral characteristics and phase dependent temperatures. However, despite these observations, the effectiveness of tidally locked planets in re-distributing the incident stellar irradiation remains an outstanding theoretical question. I will discuss past attempts at dynamical modeling and present recent results of three-dimensional full hydrodynamic models with radiative transfer. The resulting temperature distribution, significantly different then previous modeling efforts have predicted, has distinct observational consequences accessible to current facilities.

Date and Time: Tuesday, 13 Mar. 2007, 1:00 pm
Location: JPL building 169-336, Joint seminar with Astrophysics Section 326
Speaker: Dr. Nick Gautier, Kepler Project Scientist

Title: "Introduction to KEPLER for Participating Scientists"

Abstract: I will discuss the Kepler Project and its Participating Scientists Program. I will discuss how JPL scientists can respond to the ROSES-2007 NRA, in which the Kepler opportunity is described in Appendix D-10. I expect to summarize the mission objectives and mission design. I will cover the instrument design and capabilities, and discuss the science capabilities of Kepler. Finally I'll talk about the opportunities and expectations for the Participating Scientists and try to answer any questions that may not be covered in the description in the NRA.

Date and Time: Wednesday, 14 Mar. 2007, 12:15 pm
Location: Morrisroe Bldg (IPAC), Room 102 (left as you enter), Joint Seminar with IPAC
Speaker: Dr. Mark Swain

Title: "The mid-infrared spectrum of the transiting exoplanet HD 209458b"

Abstract: We report the spectroscopic detection of mid-infrared emission from the transiting exoplanet HD 209458b. Using archive data taken with the Spitzer/IRS instrument, we have determined the spectrum of HD 209458b between 8.25 and 13.25 microns with an average SNR of ~4 in each 0.25 micron spectral channel. We have used two independent methods to determine the planet spectrum and find the results are in good agreement. In the mid-infrared, the planet spectrum is dominated by thermal emission with a temperature consistent with previous estimates. The absence of strong spectral features is significant and is consistent with emission at these wavelengths originating primarily from optically thick clouds located at relatively high elevation in the planet's atmosphere. This work required development of improved methods for Spitzer/IRS data calibration that increase the achievable dynamic range for observations of bright point sources.

Date and Time: Monday, 2 Apr. 2007, 3:00 pm
Location: Caltech campus, Morrisroe Bldg (IPAC), room 102 (left as you enter)
Speaker: Dr. Thomas Hearty, JPL Staff Scientist

Title: "A Library of Whole Earth Spectra with the Atmospheric Infrared Sounder"

Abstract: We have investigated mid-IR spectra of Earth obtained by the Atmospheric Infrared Sounder (AIRS) instrument on-board the AQUA spacecraft to explore the characteristics that may someday be observed in extrasolar terrestrial planets.

We have used the AIRS infrared (R ~ 1200; 3.75-15.4 microns) spectra to construct directly-observed high-resolution spectra of the only known life bearing planet, Earth. The AIRS spectra are the first such spectra that span the seasons. We also used the 4 Visible/Near-Infrared Channels of AIRS to investigate the vegetation signatures that might be observed in the visible. Additionally, we investigated the diurnal and seasonal variations as well as spectral variations that would arise due to varying cloud amount and viewing geometry.

Date and Time: Monday, 16 Apr. 2007, 3:00pm
Location: JPL building 169-336 conference room
Speaker: Dr. Carl Grillmair, Spitzer Science Center

Title: "A Spitzer Spectrum of Exoplanet HD 189733b"

Abstract: We report on the measurement of the 7.5-14.7 micron spectrum for the transiting extrasolar giant planet HD 189733b using the Infrared Spectrograph on the Spitzer Space Telescope. Though the observations comprise only 12 hours of telescope time, the continuum is well measured and has a flux ranging from 0.6 mJy to 1.8 mJy over the wavelength range, or 0.49 +/- 0.02 of the flux of the parent star. The variation in the measured fractional flux is very nearly flat over the entire wavelength range and shows no indication of significant absorption by water or methane, in contrast with the predictions of most atmospheric models.

Date and Time: Monday, 11 Jun. 2007, 3:00 pm
Location: JPL building 169-336
Speaker: Vincent Coude du Foresto, LESIA, Observatoire de Paris

Title: "Prospects for nulling interferometry from Antarctica"

Abstract: The high Antarctic plateau is known to be a very unique environment whose main characteristics make it a premier site for high angular resolution, high dynamic range observations at infrared wavelengths. This is due to a combination of cold temperatures (low emissivity), dry air (infrared transparency), and a night time atmospheric turbulence which is concentrated in the first ~30m near the ground (which results in a large isoplanetic angle). Above that turbulent layer (a location that can be reached either by support structures or tethered balloons), the free air seeing is both exceptionally benign and slow. In this talk I will review the performances and outline a potential programme for an Antarctic nulling interferometer, using the ALADDIN concept proposed to ESA as a reference design. Comparative simulations show that a small dedicated interferometer (two 1m-class telescopes) equipped with a nuller instrument performs better than the same instrument behind 8m-class telescopes on a temperate site. It can characterize the distribution of dust emission around nearby main sequence stars and establish the prevalence of sources whose IR excess in the habitable zone would prevent exoearth detection, a necessary precursor science for Darwin and TPF-I. The nature of the site, intermediate between ground and space both in potential and technical challenge, adds particular relevance to the demonstration of nulling for a space mission.

Date and Time: Thursday, 12 Jul. 2007, 12:15 pm
Location: Caltech campus, Morrisroe Bldg (IPAC), room 102 (left as you enter)
Speaker: Daniel Anger, Graduate Student, University of Koln, Germany

Title: "Phase-differential NIR integral-field spectroscopy of transiting extrasolar planets"

Abstract: The technique of choice for spectroscopy of transiting extrasolar planets is to cancel the stellar contribution by using a differential method: Before the planet is disappearing during a superior conjunction (SC) or after its recurrence the observable signal is the sum of the light from the planet, the star, and various background contributions. During the SC, only the planetary contribution is missing, while during an inferior conjunction (IC) the planetary atmosphere absorbs parts of the stellar signal. Analyzing the differences between both observations should reveal the planetary spectrum.

I will present results of an exploratory study to use adaptive optics-assisted integral field spectroscopy to obtain H- and K-band spectra of transiting Hot Jupiters and emphasize the importance of observing strategy and exact timing. I will demonstrate how integral field spectroscopy compares with other spectroscopic techniques currently applied.

Date and Time: Thursday, 8 Nov. 2007,4-5pm
Location: JPL building 169-336
Speaker: Prof. N. Jeremy Kasdin, Mechanical and Aerospace Engineering, Princeton University

Title: "Coronagraphs for Imaging Planets from Space"

Abstract: Near at hand is the opportunity to image, for the first time in human history, possibly life-bearing planets about other stars. NASA is currently debating about the best approach for accomplishing a planet finding and characterization mission and the upcoming Decadel Survey will be addressing planet finding among the missions it must prioritize. Central to this conversation is the technology for achieving the starlight suppression needed to detect and characterize an Earthlike exoplanet. Well over a dozen different coronagraph approaches have been proposed over the past decade for accomplishing this. In this talk I will focus on three of them: bandlimited Lyot, shaped pupil, and pupil remapping coronagraphs. I will discuss the basic principals, performance, and laboratory results. In particular, I will focus on their responses in the presence of aberrations and how we integrate wavefront control systems with them to achieve the high contrast we desire. In fact, when considered in combination with deformable mirrors for correction, all of these coronagraphs become simply special cases of a single, hybrid system. I will conclude with progress being made on understanding and optimizing this hybrid coronagraph/wavefront control system.

Date and Time: Monday, 3 December 2007, 12:00 noon
Location: JPL building 169-336
Speaker: Geoff Bower, UC Berkeley

Title: "Radio Interferometric Planet Search (RIPL)"

Abstract: I will describe a new program to search for planets around low mass stars. The Radio Interferometric Planet Search (RIPL) uses the Very Long Baseline Array to detect the astrometric signature of planets orbiting low mass stars. The amplitude of the astrometric signature for a Jupiter mass planet orbiting an M dwarf at a radius of 1 AU is on the order of 1 milli-arcsecond, while the astrometric accuracy of the VLBA is better than 0.1 milli-arcsecond.

RIPL fills an important, largely unexplored volume in the parameter space of planet searches. Its sensitivity is primarily to planets at a radius of an AU or greater and it focuses on low mass, active stars that are difficult or impossible to study with radial velocity techniques. I will describe results of the VLBA Preliminary Astrometric Survey (VPAS) which shows that activity in M dwarfs does not prevent us from obtaining better than 0.2 milli-arcsecond astrometric accuracy. The VPAS already excludes brown dwarf companions for several stars. I will then describe RIPL, a 1400-hour, 3-year program with the VLBA and the Green Bank 100 meter telescope that will survey 29 stars in 12 epochs and achieve better than Jovian mass sensitivity.

Past Colloquia - 2008

Date and Time: Thur, 24 January 2008, 4:00 p.m.
(Coffee & Cookies at 3:45 p.m.)
Location: JPL building 169-336
Speaker: Mark Marley, NASA Ames

Title: The Planetary Science of Exoplanets

Abstract: Thanks to the direct detection of flux from extrasolar planets by Spitzer, we have now entered the era of characterization of extrasolar planets.

As we look to maximize the scientific return from available data and look forwards to direct detection of exoplanets, the insights gained from decades of Solar System exploration and characterization should not be forgotten. Likewise the campaign to understand brown dwarfs, which overlaps the temperature regime of the known hot and warm Jupiters can likewise provide insight. In this talk I will discuss our efforts to model the atmospheres of extrasolar planets. I will draw connections between processes acting in the Solar System and brown dwarf atmospheres. In particular I will highlight the importance of clouds and hazes in controlling the spectra of planets and explore how these processes will impact our ability to interpret the spectra of exoplanets. I will also highlight our group's recent efforts to understand the heating mechanism in the stratospheres of hot Jupiters and explore models of atmospheric dynamics in these extreme worlds.

Date and Time: Mon 14 January 2008, 12:00 noon
Location: von Karman Auditorium
Speaker: Dr. Mark Swain, JPL's Origins of Stars and Planets Group

Title: Detection and Characterization of Exoplanet Atmospheres

Abstract: The last two years have seen extraordinary progress in the field of detecting and characterizing exoplanet atmospheres. This progress has been aided by the rapid discovery rate for exoplanets together with powerful new methods that now enable detailed atmospheric characterization. Recent successes include a "map" of atmospheric temperature and the detection of water in an exoplanet atmosphere. Today, with existing instruments, we are capable of determining the atmospheric composition and weather of some exoplanets. This remarkable process is building rapidly towards the next step; in the very near future, it is probable that we will be able to detect prebiotic molecules in a habitable zone exoplanet. This talk will tell the story of the journey from the discovery of exoplanets to current efforts to detect organic molecules in exoplanet atmospheres.

Date and Time: Thur, 24 January 2008, 4:00 p.m.
(Coffee & Cookies at 3:45 p.m.)
Location: JPL building 169-336
Speaker: Mark Marley, NASA Ames

Title: The Planetary Science of Exoplanets

Abstract: Thanks to the direct detection of flux from extrasolar planets by Spitzer, we have now entered the era of characterization of extrasolar planets.

As we look to maximize the scientific return from available data and look forwards to direct detection of exoplanets, the insights gained from decades of Solar System exploration and characterization should not be forgotten. Likewise the campaign to understand brown dwarfs, which overlaps the temperature regime of the known hot and warm Jupiters can likewise provide insight. In this talk I will discuss our efforts to model the atmospheres of extrasolar planets. I will draw connections between processes acting in the Solar System and brown dwarf atmospheres. In particular I will highlight the importance of clouds and hazes in controlling the spectra of planets and explore how these processes will impact our ability to interpret the spectra of exoplanets. I will also highlight our group's recent efforts to understand the heating mechanism in the stratospheres of hot Jupiters and explore models of atmospheric dynamics in these extreme worlds.

Date and Time: Thur 31 Jan. 2008
Location: JPL building 169-336
Speaker: Douglas Lin, University of California, Santa Cruz

Title: Hot Earths Around G and M Dwarfs

Abstract: Radial velocity and transit surveys will soon be able to detect Earth-mass rocky planets close to G and M main-sequence dwarf stars. There are several avenues through which such planets may be formed. Although rocky planets may be formed in situ from the grains which migrated to the stellar proximity, their mass is likely to be severely limited by dynamical isolation. More massive rocky planets can form at modest distances from their host stars and migrate to the proximity of their stars with or without the presence of gas giant planets. Their statistical properties will provide a calibration on the efficiency of migration and the frequency of rocky planets in general. Finally, a prediction of the association of hot Earths with hot Jupiters will provide a definitive proof of the core accretion scenario.

Date and Time: Monday, Feb 4, 2008 noon
Location: Bldg 169-336, JPL
Speaker: Amir Give'on, JPL

Title: Coronagraph Wavefront Correction by Electric Field Conjugation

Abstract: Great strides have been made in recent years toward the goal of high-contrast imaging with sensitivity adequate to detect Earth-like planets around nearby stars. It appears that the hardware (optics, coronagraph masks, deformable mirrors, illumination systems and thermal control systems) is up to the task of obtaining the required 10^-10 contrast. But in broadband light (e.g., 10% bandpass) the wavefront control algorithms have been a limiting factor. In this paper we describe a general correction methodology for various types of coronagraphs (band limited coronagraph, shaped pupil coronagraph, etc.) that works in broadband light with one or more deformable mirrors by conjugating the electric field in a predefined region in the image where terrestrial planets would be found. We describe the linearized approach and demonstrate its effectiveness through laboratory experiments. This paper presents results from the JPL High Contrast Imaging Testbed (HCIT) for both narrow-band light (2% bandwidth) and broadband (10%) correction.

Date and Time: Thursday, Feb 14, 2008, 4pm
Location: Bldg 169-336, JPL
Speaker: John Asher Johnson, Institute for Astronomy, Univ. of Hawaii

Title: Planet Hunting In New Stellar Domains

Abstract: Very little is known about the occurrence rate and orbital properties of planets around A-type stars, corresponding to stellar masses ranging from 1.5 M_sun to 2.5 M_sun. This apparent lack of planets around massive stars is due to a strong selection bias against early-type, main-sequence stars in Doppler-based planet searches. A and early F stars have relatively few narrow spectral lines due to their high surface temperatures and large rotational velocities. These features make the Doppler-detection of planets around these stars exceedingly difficult. One method to circumvent the difficulties inherent to massive dwarfs is to instead observe these stars after they have evolved off of the main sequence. I'll show how the cooler atmospheres and slower rotation velocities of sub-giants make them ideal proxies for A and F stars in Doppler-based planet searches. I present the early results from our planet search, including 7 new exoplanets, and 3 additional strong candidates, orbiting stars with masses greater than 1.5 M_sun. My preliminary results reveal a paucity of planets orbiting within ~1 AU of their host stars, which is significantly different than the semi-major axis distribution of planets around Sun-like stars. I also present evidence of a steeply rising trend in giant planet occurrence with stellar mass, indicating that A stars are 4 times more likely than M dwarfs to harbor Jovian planets.

Date and Time: Mon 25 Feb. 2008, noon
Location: JPL building 169-336
Speaker: Dimitri Mawet, JPL

Title: Phase Mask Coronagraphy: Scientific Results and Perspectives

Abstract: Phase mask coronagraphs provide unique inner working distance capabilities. Coupled to an adaptive optics system, they have proven reliable in terms of scientific efficiency. In this talk, we will present results obtained at the VLT with the four-quadrant phase-mask coronagraph at NACO's focus. New advanced phase masks are under study and planned for second generation instruments. We will present the coronagraph technology chosen for SPHERE as well as recent developments concerning the vectorial vortex coronagraph here at JPL.

Date and Time: Thur 28 Feb. 2008, 4pm
Location: JPL building 169-336
Speaker: Steve Beckwith, President's Office, Univ. of California

Title: Detecting Life's Signatures in Extra-solar Planets

Abstract: TBD

Date and Time: Mon 10 March 2008, noon
Location: JPL building 169-336
Speaker: Drake Deming, GSFC

Title: Light from Extrasolar Planets

Abstract: Investigators using the Spitzer Space Telescope have detected thermal radiation emitted by planets orbiting nearby stars. These planets range in size from worlds larger than Jupiter, down to the size of Neptune. The Spitzer teams exploit the mutual eclipses of the planets and their stars in transiting systems, in order to reconstruct the broad band infrared spectra of these worlds. Currently, the EPOXI mission is working to extend these eclipse detections to visible light. I will describe what we have learned from Spitzer, what we expect to learn in the future during the Warm Spitzer mission, and what EPOXI will tell us about these transiting planet systems.

Date and Time: Thur 13 March 2008, 4pm
Location: JPL building 169-336
Speaker: Jim Feinup, Univ. of Rochester

Title: Spatially Variant Apodization for the Elimination of Sidelobes in Imagery

Abstract: TBD

Date and Time: Thur 20 March 2008, 4pm
Location: JPL building 169-336
Speaker: Aki Roberge, GSFC

Title: Gas & Dust in Debris Disks: Clues About the Late Stages of Planetary System Formation

Abstract: The basic character of debris disks was established soon after their discovery in the mid-1980's. These disks around nearby main sequence stars are composed of material (mostly dust) produced by collisions and/or evaporation of extrasolar asteroids and comets. However, fundamental observational questions about debris disks remain unanswered. How much material do debris disks typically contain and how does it evolve with time? What is the composition of the dust and gas? Are planets present or forming in the disks? Answers to these questions will provide insights into the late-stages of planetary system formation and the origins of terrestrial planet atmospheres. In this talk, I will explain our current understanding of the place of debris disks in the planet formation process. Progress toward addressing the questions given above will be discussed, with emphasis on recent and upcoming studies of the small but important gas component. Finally, I will outline the implications of debris dust for future efforts to directly image and characterize extrasolar terrestrial planets.

Date and Time: Thur 27 March 2008, 4pm
Location: JPL building 169-336
Speaker: Christophe Sotin, JPL

Title: Extrapolating Solid Earth Models to Terrestrial Exoplanets

Abstract: TBD

Date and Time: Mon. 31 March 2008, noon
Location: JPL building 169-336
Speaker: Jonathan Lunine, Univ. of Arizona

Title: Exoplanet Task Force Strategy

Abstract: TBD

Additional possible topic, time permitting: Delivery of Water to Exo-Earths: Insights From Our World

The delivery of water to planet Earth occurred early in its history, but substantial disagreement exists on the potential sources. Simulations done with groups at Boulder and the Univ. of Washington suggest that, for our own world, the asteroid belt was crucial; this suggests a potentially high degree of variability in the amount of water that habitable exo-Earths will receive.

Date and Time: Thur 3 April 2008, 4pm
Location: JPL building 169-336
Speaker: Neal Turner, JPL

Title: Where Planets Form: Dead Zones in Protostellar Disks

Abstract: Angular momentum transport is a key to planet formation because it regulates the flow of raw materials through the protostellar disk onto the young star. The magneto-rotational instability extracts angular momentum and drives turbulence by tapping the free energy in the orbital shear at locations where the gas is sufficiently ionized to couple to magnetic fields. Most of the disk is too cold for thermal ionization but is weakly conducting thanks to residual ionization by cosmic rays, radioactive decay, and protostellar X-rays and energetic protons. I will show the location of the resulting magnetically inactive "dead zone," describe 3-D MHD calculations including the feedback of the embedded dust particles on the magnetic coupling, and outline the consequences for the growth of solid bodies in protostellar disks and the orbital migration of protoplanets.

Date and Time: Mon 14 April 2008, noon
(Coffee & Cookies at 11:45 a.m.)
Location: JPL building 169-336
Speaker: Antígona Segura, Instituto de Ciencias Nucleares, UNAM

Title: Biosignatures on Habitable Planets Around Other Stars: Lessons from Earth

Abstract: As our only example of life, our planet has shown us the complex interaction between the biosphere and the geologic and atmospheric processes. On this talk I will present what we have learned from Earth and how we are using this knowledge to determine what signatures we should expect from habitable planets around other stars.

Date and Time: Thur 24 April 2008, 4pm
Location: JPL building 169-336
Speaker: Peter Plavchan, Caltech

Title: Unveiling disks around M stars

Abstract: TBD

Date and Time: Thur 1 May 2008, 4pm
Location: JPL building 169-336
Speaker: Ellyn Baines, CHARA, Georgia State University

Title: TBS

Abstract: TBD

Date and Time: Thur 15 May 2008, 4pm
Location: JPL building 169-336
Speaker: Malcolm Fridlund, ESA COROT Project Scientist; Study Scientist PLATO mission; Secretary for Exo-Planet Roadmap Advisory Team (EP-RAT); Astrophysics Mission Division, Research and Scientific Support Department, ESA, ESTEC, SCI-SA

Title: Exoplanetary Missions: Yesterday, Today and Tomorrow

Abstract: More than 12 years ago ESA began to study a large mission -- known as Darwin -- to search for and characterize in detail terrestrial exoplanets. Today this mission is considered to be too large and uncertain to implement without preparatory exploration of the search space. The good news is that this activity is in full swing on both sides of the Atlantic.

The CoRoT mission is flying and producing data. The Kepler mission will come soon. More and more the subject of exoplanets in general and terrestrial exoplanets in particular becomes important for missions such as JWST and SPICA.

Further exploratory missions are planned. An example on the ESA side is PLATO. Both in the US and now in Europe comprehensive strategy planning has been and is being planned in order to come up with a roadmap for an exploration that ends with the capability of detecting biomarkers on planets orbiting other stars.

Date and Time: Mon 19 May 2008, noon
Location: JPL building 169-336
Speaker: Thayne Currie, UCLA/CfA

Title: TBS

Abstract: TBD

Date and Time: Thur 22 May 2008
Location: JPL building 169-336
Speaker: Gene Serabyn, JPL

Title: Keck/Palomar

Abstract: TBD

Date and Time: Thur 22 May 2008 4:00 p.m.
(Coffee & Cookies at 3:45 p.m.)
Location: JPL building 169-336
Speaker: Dimitri Mawet earned his PhD at the University of Liege in 2006, was an ESA postdoc at Liege from 2006-2007, and came to JPL as a NASA postdoc working with Gene Serabyn in 2007.

Title: Phase-Mask Coronagraphy: Scientific Results and Perspectives

Abstract: Phase-mask coronagraphs provide unique inner working distance capabilities. Coupled to an adaptive optics system, they have proven reliable in terms of scientific efficiency. In this talk, I will present results obtained at the VLT with the four-quadrant phase-mask coronagraph at NACO's focus, as well as results obtained at the Palomar 5-m telescope using the Well-Corrected Subaperture. New advanced phase masks are under study and planned for second-generation instruments. I will present the coronagraph technology chosen for SPHERE as well as recent developments around the vectorial vortex coronagraph here at JPL.

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Date and Time: Mon 2 June 2008, noon
Location: JPL building 169-336
Speaker: Ming Zhao, Univ. of Michigan

Title: Closure Phase Studies Toward Direct Detection of Light from Hot Jupiters

Abstract: TBD

Date and Time: Thur 5 June 2008, 4:00 p.m.
(Coffee & Cookies at 3:45 p.m.)
Location: JPL building 169-336
Speaker: Christian Marois, Herzberg Institute of Astrophysics, BC, Canada

Title: Direct Exoplanet Detection with Ground-Based Telescopes

Abstract: The first unambiguous detection in 1995 of a substellar object in orbit around a star, Gl229b, was the only successful direct imaging discovery during a period of several years, in spite of numerous attempts by other groups. These early surveys were mostly sensitive to brown dwarfs, but now, using more advanced adaptive optics systems, optimized acquisition strategies, and data reduction schemes, surveys are now reaching the planet regime. The first statistical analyses of the exoplanet population at wide (>30AU) separations are now being compiled. Such analysis is fundamental to constrain the planet formation mechanism in the outskirts of circumstellar disks. I will first discuss our latest nearby/young 80-star adaptive optics imaging survey result obtained at the Gemini telescope with Altair/NIRI using the very successful angular differential imaging technique. I will also present our second-generation ongoing international survey to acquire higher-mass stars and explore possible biases. Although these surveys have currently achieved one of the best on-sky contrast curves to date, they are still limited at small angular separations by a quasi-static speckle noise and by varying observing conditions. I will briefly describe the current effort by our group to design and build a high-order adaptive optics system to reach 10-7 contrast at a few lambda/D. Such system will have the sensitivity to directly detect for the first time young (~100 Myr) Jovian-like planets in orbits similar to the ones of our solar system. This instrument, called the Gemini Planet Imager, is scheduled for first light at Gemini south in 2010.

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Date and Time: Mon 9 June 2008, noon
Coffee & Cookies at 11:45 a.m.
Location: JPL building 169-336
Speaker: Eugene Serabyn, JPL

Title: Detection of excess mid-infrared emission very close to Vega with the Keck Interferometer Nuller

Abstract: The Keck Interferometer Nuller (KIN) was developed to search for faint exozodiacal emission around nearby stars. During the now-completed shared-risk phase, several stars were observed with the KIN, and one of our first results is the detection of excess emission around Vega. The measurement and implications of Vega's excess will be discussed. The implied distribution of exozodiacal dust in the Vega system seems to be quite different from that in our own solar system.

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