Lucianne M. Walkowicz
A5046983214- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Space Science and Extraterrestrial Life
- History and Developments in Astronomy
- Solar and Space Plasma Dynamics
- Space Exploration and Technology
- Adaptive optics and wavefront sensing
- Galaxies: Formation, Evolution, Phenomena
- Space exploration and regulation
- Scientific Computing and Data Management
- Planetary Science and Exploration
- Big Data and Business Intelligence
- Distributed and Parallel Computing Systems
- Computational Physics and Python Applications
- Data Analysis with R
- Satellite Communication Systems
- Astronomical and nuclear sciences
- CCD and CMOS Imaging Sensors
- Historical Astronomy and Related Studies
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
Adler Planetarium
2016-2022
DigitalSpace (United States)
2022
Digital Research Alliance of Canada
2021
Large Synoptic Survey Telescope Corporation
2020
Library of Congress
2019
Max Planck Society
2018
Princeton University
2011-2015
Princeton Public Schools
2013
University of California, Berkeley
2009-2012
Ames Research Center
2011
The Kepler mission was designed to determine the frequency of Earth-sized planets in and near habitable zone Sun-like stars. is region where planetary temperatures are suitable for water exist on a planet's surface. During first 6 weeks observations, monitored 156,000 stars, five new exoplanets with sizes between 0.37 1.6 Jupiter radii orbital periods from 3.2 4.9 days were discovered. density Neptune-sized Kepler-4b similar that Neptune GJ 436b, even though irradiation level 800,000 times...
On 2011 February 1 the Kepler mission released data for 156,453 stars observed from beginning of science observations on 2009 May 2 through September 16. There are 1235 planetary candidates with transit-like signatures detected in this period. These associated 997 host stars. Distributions characteristics separated into five class sizes: 68 approximately Earth-size (Rp < 1.25 R⊕), 288 super-Earth-size (1.25 R⊕ ⩽ Rp 662 Neptune-size (2 6 165 Jupiter-size (6 15 and 19 up to twice size Jupiter...
New transiting planet candidates are identified in 16 months (2009 May-2010 September) of data from the Kepler spacecraft.Nearly 5000 periodic transit-like signals vetted against astrophysical and instrumental false positives yielding 1108 viable new candidates, bringing total count up to over 2300.Improved vetting metrics employed, contributing higher catalog reliability.Most notable is noise-weighted robust averaging multiquarter photo-center offsets derived difference image analysis that...
The Kepler Mission is uniquely suited to study the frequencies of extrasolar planets. This goal requires knowledge incidence false positives such as eclipsing binaries in background targets, or physically bound them, which can mimic photometric signal a transiting planet. We perform numerical simulations predict occurrence astrophysical detectable by Mission, and quantify fraction them that would pass candidate vetting procedure. By comparing their distribution with Objects Interest detected...
We report the distribution of planets as a function planet radius (R_p), orbital period (P), and stellar effective temperature (Teff) for P < 50 day orbits around GK stars. These results are based on 1,235 (formally "planet candidates") from Kepler mission that include nearly complete set detected small 2 Earth radii (Re). For each 156,000 target stars we assess detectability R_p P. also correct geometric probability transit, R*/a. consider first within "solar subset" having Teff = 4100-6100...
NASA's Kepler Mission uses transit photometry to determine the frequency of earth-size planets in or near habitable zone Sun-like stars. The mission reached a milestone toward meeting that goal: discovery its first rocky planet, Kepler-10b. Two distinct sets events were detected: 1) 152 +/- 4 ppm dimming lasting 1.811 0.024 hours with ephemeris T[BJD]=2454964.57375+N*0.837495 days and 2) 376 9 6.86 0.07 T[BJD]=2454971.6761+N*45.29485 days. Statistical tests on photometric pixel flux time...
The Kepler spacecraft is monitoring more than 150,000 stars for evidence of planets transiting those stars. We report the detection two Saturn-size that transit same Sun-like star, based on 7 months observations. Their 19.2- and 38.9-day periods are presently increasing decreasing at respective average rates 4 39 minutes per orbit; in addition, times inner body display an alternating variation smaller amplitude. These signatures characteristic gravitational interaction near a 2:1 orbital...
Main sequence M stars pose an interesting problem for astrobiology: their abundance in our galaxy makes them likely targets the hunt habitable planets, but strong chromospheric activity produces high-energy radiation and charged particles that may be detrimental to life. We studied impact of 1985 April 12 flare from dwarf AD Leonis (AD Leo), simulating effects both UV protons on atmospheric chemistry a hypothetical, Earth-like planet located within its zone. Based observations solar proton...
An extensive sample of M, L and T dwarfs identified in the Sloan Digital Sky Survey (SDSS) has been compiled. The 718 includes 677 new objects (629 M dwarfs, 48 dwarfs) together with 41 that have previously published. All some published ones optical spectra obtained either SDSS spectrographs or Apache Point Observatory 3.5m ARC telescope. Spectral types colors are available for all objects; approximately 35% also near-infrared magnitudes measured by 2MASS on Mauna Kea system. We use this to...
Ground- and space-based planet searches employing radial velocity techniques transit photometry have detected thousands of planet-hosting stars in the Milky Way. The chemistry these atmospheres is controlled by shape absolute flux stellar spectral energy distribution, however, distributions relatively inactive low-mass are poorly known at present. To better understand exoplanets orbiting stars, we executed a panchromatic (X-ray to mid-IR) study 11 nearby hosting {\it Measurements Ultraviolet...
In the spring of 2009, Kepler Mission commenced high-precision photometry on nearly 156,000 stars to determine frequency and characteristics small exoplanets, conduct a guest observer program, obtain asteroseismic data wide variety stars. On 15 June 2010 released from first quarter observations. At time this publication, 706 set have exoplanet candidates with sizes as that Earth larger than Jupiter. Here we give identity 306 planetary candidates. Data for remaining 400 will be in February...
The spectral and temporal behavior of exoplanet host stars is a critical input to models the chemistry evolution planetary atmospheres. Ultraviolet photons influence atmospheric temperature profiles production potential biomarkers on Earth-like planets around these stars. At present, little observational or theoretical basis exists for understanding ultraviolet spectra M dwarfs, despite their importance predicting interpreting potentially habitable as they are obtained in coming decades....
The ultraviolet (UV) spectral energy distributions of low-mass (K- and M-type) stars play a critical role in the heating chemistry exoplanet atmospheres, but are not observationally well-constrained. Direct observations intrinsic flux Lyman alpha line (the dominant source UV photons from stars) challenging, as interstellar HI absorbs entire core for even closest stars. To address existing gap empirical constraints on K M dwarfs, MUSCLES HST Treasury Survey has obtained 11 nearby dwarfs...
We present rotation periods for 71 single dwarf members of the open cluster NGC6811 determined using photometry from NASA's Kepler Mission. The results are first Cluster Study which combine Kepler's with ground-based spectroscopy membership and binarity. delineate a tight sequence in color-period diagram ~1 day at mid-F to ~11 days early-K spectral type. This result extends Gyr similar prior ~600 Myr Hyades Praesepe clusters, suggesting that cool stars well-defined surface 3-dimensional...
We present a spectroscopic analysis of nearly 8000 late-type dwarfs in the Sloan Digital Sky Survey. Using Halpha emission line as an activity indicator, we investigate fraction active stars function spectral type and find peak near M8, confirming previous results. In contrast to past findings, that not all M7-M8 are active. show this may be selection effect distance distributions samples, appear concentrated Galactic Plane. also examine strength (ratio luminosity emitted bolometric...
We present the results of a search for white light flares on ~23,000 cool dwarfs in Kepler Quarter 1 long cadence data. have identified 373 flaring stars, some which flare multiple times during observation period. calculate relative energies, rates and durations, compare these with quiescent photometric variability our sample. find that M tend to more frequently but shorter durations than K dwarfs, they emit energy their luminosity given dwarfs. Stars are photometrically variable quiescence...
We report rotation periods, variability characteristics, gyrochronological ages for ∼950 of the Kepler Object Interest host stars. find a wide dispersion in amplitude photometric as function rotation, likely indicating differences spot distribution among use these periods combination with published spectroscopic measurements v sin i and stellar parameters to derive inclination line sight, number systems possible spin–orbit misalignment. additionally several close-in planet candidates whose...
The Kepler mission provides an exciting opportunity to study the light curves of stars with unprecedented precision and continuity coverage. This is first look at a large sample photometric data quality that has heretofore been only available for our Sun. It compare irradiance variations Sun cohort ranging from very similar rather different stellar properties, wide variety ages. Although are in early phase maturity, we analyze month coverage, it sufficient garner meaningful measurements...
We provide an overview of stellar variability in the first quarter data from Kepler mission. The intent this paper is to examine entire sample over 150,000 target stars for periodic behavior their light curves and relate characteristics. This set constitutes unprecedented study given its great precision complete time coverage (with a half hour cadence). Because full pipeline not currently suitable sort, we describe our procedures treating "raw" data. About total exhibits convincing up two...
Kepler Mission results are rapidly contributing to fundamentally new discoveries in both the exoplanet and asteroseismology fields. The data returned from unique terms of number stars observed, precision photometry for time series observations, temporal extent high duty cycle observations. As first mission provide extensive measurements on thousands over months years at a level hitherto possible only Sun, will vastly increase our knowledge stellar variability quiet solar-type stars. Here we...
We utilize Kepler data to study the precision differential photometric variability of solar-type and cooler stars at different timescales, ranging from half an hour three months. define a diagnostic that characterizes median intensity change between bins given timescale. apply same diagnostics Solar Heliospheric Observatory has been rendered comparable Kepler. The Sun exhibits similar on all timescales as in field. previously defined "range" serves our activity proxy (driven by starspot...
We present the discovery of Kepler-20 planetary system, which we initially identified through detection five distinct periodic transit signals in Kepler light curve host star 2MASS J19104752+4220194. From high-resolution spectroscopy star, find a stellar effective temperature Teff = 5455 ± 100 K, metallicity [Fe/H] 0.01 0.04, and surface gravity log g 4.4 0.1. combine these estimates with an estimate density derived from curves to deduce mass M⋆ 0.912 0.034 M☉ radius R⋆ 0.944+0.060−0.095 R☉....
The Large Synoptic Survey Telescope is designed to provide an unprecedented optical imaging dataset that will support investigations of our Solar System, Galaxy and Universe, across half the sky over ten years repeated observation. However, exactly how LSST observations be taken (the observing strategy or "cadence") not yet finalized. In this dynamically-evolving community white paper, we explore detailed performance anticipated science expected depend on small changes strategy. Using...
Abstract We present the discovery and validation of a three-planet system orbiting nearby (31.1 pc) M2 dwarf star TOI-700 (TIC 150428135). lies in TESS continuous viewing zone Southern Ecliptic Hemisphere; observations spanning 11 sectors reveal three planets with radii ranging from 1 R ⊕ to 2.6 orbital periods 9.98 37.43 days. Ground-based follow-up combined diagnostic vetting tests enables us rule out common astrophysical false-positive scenarios validate planets. The outermost planet, d,...