The JWST Early Release Science Program for the Direct Imaging and Spectroscopy of Exoplanetary Systems

The direct characterization of exoplanetary systems with high-contrast imaging is among the highest priorities for the broader exoplanet community. As large space missions will be necessary for detecting and characterizing exo-Earth twins, developing the techniques and technology for direct imaging of exoplanets is a driving focus for the community. For the first time, JWST will directly observe extrasolar planets at mid-infrared wavelengths beyond 5 μm, deliver detailed spectroscopy revealing much more precise chemical abundances and atmospheric conditions, and provide sensitivity to analogs of our solar system ice-giant planets at wide orbital separations, an entirely new class of exoplanet. However, in order to maximize the scientific output over the lifetime of the mission, an exquisite understanding of the instrumental performance of JWST is needed as early in the mission as possible. In this paper, we describe our 55 hr Early Release Science Program that will utilize all four JWST instruments to extend the characterization of planetary-mass companions to ∼15 μm as well as image a circumstellar disk in the mid-infrared with unprecedented sensitivity. Our program will also assess the performance of the observatory in the key modes expected to be commonly used for exoplanet direct imaging and spectroscopy, optimize data calibration and processing, and generate representative data sets that will enable a broad user base to effectively plan for general observing programs in future Cycles

Simulating medium-spectral-resolution exoplanet characterization with SCALES angular/reference differential imaging

SCALES (Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy) is a 2 - 5 micron high-contrast lenslet-based integral field spectrograph (IFS) designed to characterize exoplanets and their atmospheres. The SCALES medium-spectral-resolution mode uses a lenslet subarray with a 0.34 x 0.36 arcsecond field of view which allows for exoplanet characterization at increased spectral resolution. We explore the sensitivity limitations of this mode by simulating planet detections in the presence of realistic noise sources. We use the SCALES simulator scalessim to generate high-fidelity mock observations of planets that include speckle noise from their host stars, as well as other atmospheric and instrumental noise effects. We employ both angular and reference differential imaging as methods of disentangling speckle noise from the injected planet signals. These simulations allow us to assess the feasibility of speckle deconvolution for SCALES medium resolution data, and to test whether one approach outperforms another based on planet angular separations and contrasts

The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems: Best Practices for Data Collection in Cycle 2 and Beyond

We present a set of recommended best practices for JWST data collection for members of the community focussed on the direct imaging and spectroscopy of exoplanetary systems. These findings and recommendations are based on the early analysis of the JWST Early Release Science Program 1386, "High-Contrast Imaging of Exoplanets and Exoplanetary Systems with JWST." Our goal is for this information to be useful for observers in preparation of JWST proposals for Cycle 2 and beyond. In addition to compiling a set of best practices from our ERS program, in a few cases we also draw on the expertise gained within the instrument commissioning programs, as well as include a handful of data processing best practices. We anticipate that this document will be regularly updated and resubmitted to arXiv.org to ensure that we have distributed our knowledge of best-practices for data collection as widely and efficiently as possible.Comment: Not yet submitted for publication. Intended only to be a community resource for JWST Cycle 2 proposal

Haze in Pluto's atmosphere: Results from SOFIA and ground-based observations of the 2015 June 29 Pluto occultation

On UT 29 June 2015, the occultation by Pluto of a bright star (r′ = 11.9) was observed from the Stratospheric Observatory for Infrared Astronomy (SOFIA) and several ground-based stations in New Zealand and Australia. Pre-event astrometry allowed for an in-flight update to the SOFIA team with the result that SOFIA was deep within the central flash zone (~22 km from center). Analysis of the combined data leads to the result that Pluto's middle atmosphere is essentially unchanged from 2011 and 2013 (Person et al. 2013; Bosh et al. 2015); there has been no significant expansion or contraction of the atmosphere. Additionally, our multi-wavelength observations allow us to conclude that a haze component in the atmosphere is required to reproduce the light curves obtained. This haze scenario has implications for understanding the photochemistry of Pluto's atmosphere

Direct imaging and spectroscopy of exoplanetary systems with the JWST early release science program

The direct characterization of exoplanetary systems with high contrast imaging is among the highest priorities for the broader exoplanet community. As large space missions will be necessary for detecting and characterizing exo-Earth twins, developing the techniques and technology for direct imaging of exoplanets is a driving focus for the community. For the first time, JWST will directly observe extrasolar planets at mid-infrared wavelengths beyond 5 μm, deliver detailed spectroscopy revealing much more precise chemical abundances and atmospheric conditions, and provide sensitivity to analogs of our solar system ice-giant planets at wide orbital separations, an entirely new class of exoplanet. However, in order to maximise the scientific output over the lifetime of the mission, an exquisite understanding of the instrumental performance of JWST is needed as early in the mission as possible. In this paper, we describe our 55-hour Early Release Science Program that will utilize all four JWST instruments to extend the characterisation of planetary mass companions to ∼15-20 μm as well as image a circumstellar disk in the mid-infrared with unprecedented sensitivity. Our program will also assess the performance of the observatory in the key modes expected to be commonly used for exoplanet direct imaging and spectroscopy, optimize data calibration and processing, and generate representative datasets that will enable a broad user base to effectively plan for general observing programs in future cycles

The JWST Early Release Science Program for the Direct Imaging and Spectroscopy of Exoplanetary Systems

The direct characterization of exoplanetary systems with high-contrast imaging is among the highest priorities for the broader exoplanet community. As large space missions will be necessary for detecting and characterizing exo-Earth twins, developing the techniques and technology for direct imaging of exoplanets is a driving focus for the community. For the first time, JWST will directly observe extrasolar planets at mid-infrared wavelengths beyond 5 μm, deliver detailed spectroscopy revealing much more precise chemical abundances and atmospheric conditions, and provide sensitivity to analogs of our solar system ice-giant planets at wide orbital separations, an entirely new class of exoplanet. However, in order to maximize the scientific output over the lifetime of the mission, an exquisite understanding of the instrumental performance of JWST is needed as early in the mission as possible. In this paper, we describe our 55 hr Early Release Science Program that will utilize all four JWST instruments to extend the characterization of planetary-mass companions to ∼15 μm as well as image a circumstellar disk in the mid-infrared with unprecedented sensitivity. Our program will also assess the performance of the observatory in the key modes expected to be commonly used for exoplanet direct imaging and spectroscopy, optimize data calibration and processing, and generate representative data sets that will enable a broad user base to effectively plan for general observing programs in future Cycles

Imaging Planet Formation Inside the Diffraction Limit

For decades, astronomers have used observations of mature planetary systems to constrain planet formation theories, beginning with our own solar system and now the thousands of known exoplanets. Recent advances in instrumentation have given us a direct view of some steps in the planet formation process, such as large-scale protostar and protoplanetary disk features and evolution. However, understanding the details of how planets accrete and interact with their environment requires direct observations of protoplanets themselves. Transition disks, protoplanetary disks with inner clearings that may be caused by forming planets, are the best targets for these studies. Their large distances, compared to the stars normally targeted for direct imaging of exoplanets, make protoplanet detection difficult and necessitate novel imaging techniques. In this dissertation, I describe the results of using non-redundant masking (NRM) to search for forming planets in transition disk clearings. I first present a data reduction pipeline that I wrote to this end, using example datasets and simulations to demonstrate reduction and imaging optimizations. I discuss two transition disk NRM case studies: T Cha and LkCa 15. In the case of T Cha, while we detect significant asymmetries, the data cannot be explained by orbiting companions. The fluxes and orbital motion of the LkCa 15 companion signals, however, can be naturally explained by protoplanets in the disk clearing. I use these datasets and simulated observations to illustrate the effects of scattered light from transition disk material on NRM protoplanet searches. I then demonstrate the utility of the dual-aperture Large Binocular Telescope Interferometer's NRM mode on the bright B[e] star MWC 349A. I discuss the implications of this work for planet formation studies as well as future prospects for NRM and related techniques on next generation instruments

A TIGHT CONNECTION BETWEEN GAMMA-RAY OUTBURSTS AND PARSEC-SCALE JET ACTIVITY IN THE QUASAR 3C 454.3

We analyze the multi-frequency behavior of the quasar 3C 454.3 during three prominent γ-ray outbursts: 2009 Autumn, 2010 Spring, and 2010 Autumn. The data reveal a repeating pattern, including a triple flare structure, in the properties of each γ-ray outburst, which implies similar mechanism(s) and location for all three events. The multi-frequency behavior indicates that the lower frequency events are co-spatial with the γ-ray outbursts, although the γ-ray emission varies on the shortest timescales. We determine that the variability from UV to IR wavelengths during an outburst results from a single synchrotron component whose properties do not change significantly over the different outbursts. Despite a general increase in the degree of optical linear polarization during an outburst, the polarization drops significantly at the peak of the γ-ray event, which suggests that both shocks and turbulent processes are involved. We detect two disturbances (knots) with superluminal apparent speeds in the parsec-scale jet associated with the outbursts in 2009 Autumn and 2010 Autumn. The kinematic properties of the knots can explain the difference in amplitudes of the γ-ray events, while their millimeter-wave polarization is related to the optical polarization during the outbursts. We interpret the multi-frequency behavior within models involving either a system of standing conical shocks or magnetic reconnection events located in the parsec-scale millimeter-wave core of the jet. We argue that γ-ray outbursts with variability timescales as short as ~3 hr can occur on parsec scales if flares take place in localized regions such as turbulent cells.Academy of FinlandUnited States. National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant NNX08AW56G)United States. National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant NNX09AU93G)Russian Foundation for Basic Research (RFBR grant 12-02-00452)Russian Foundation for Basic Research (RFBR 12-02-31193)Andalusia (Spain) (P09-FQM-4784)Spain. Ministerio de Economía y Competitividad (grant AYA2010-14844)United States. National Aeronautics and Space Administration (NASA via Herschel RSA 1427799, Guest Investigator) )United States. National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant grant NNX11AAO85G)Smithsonian InstitutionAcademia Sinica (Beijing, China)Georgian National Science Foundation (grant GNSF/ST09/4-521)United States. National Aeronautics and Space Administration (NASA contract NAS5- 00136

Pluto's atmosphere from the May 22, 2011 stellar occultation

Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (pages 40-41).This paper reports the observations and atmospheric fitting results from the May 22, 2011 stellar occultation by Pluto. Of the nine sites across the United States that attempted to observe the event, three obtained light curves at the predicted midtime without being clouded out. Simultaneous fitting of these three light curves utilizing a model fully detailed in Elliot and Young [1992] resulted in a best fit half-light radius of 1309 ± 25 km, a calculated temperature of 94 ± 4 K, and a calculated pressure scale height of 55 ± 2 km. These parameters, in the context of the previous occultations, reveal a trend in which Pluto's half-light radius has been increasing slightly since an initial dramatic increase between 1988 and 2002. While the pressure scale height has remained relatively constant, the temperature has decreased slightly over the recorded events. The changes in half-light radius agree with frost migration models in which Pluto's surface has a low thermal inertia [Hansen and Paige, 1996; Elliot et al., 2007], but further constraints on frost migration model parameters such as substrate and frost albedo, frost emissivity, and the supply of N2 require additional observations. The New Horizons spacecraft should encounter a dynamic atmosphere on Pluto during the scheduled fly by in 2015.by Stephanie E. Sallum.S.B