A5058611880- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Particle physics theoretical and experimental studies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Quantum Chromodynamics and Particle Interactions
- Astrophysical Phenomena and Observations
- Dark Matter and Cosmic Phenomena
- Calibration and Measurement Techniques
- Atomic and Subatomic Physics Research
- Space Exploration and Technology
- High-Energy Particle Collisions Research
- Astrophysics and Cosmic Phenomena
- Spacecraft and Cryogenic Technologies
- Particle Accelerators and Free-Electron Lasers
- Galaxies: Formation, Evolution, Phenomena
- Geophysics and Gravity Measurements
- Space Science and Extraterrestrial Life
- Neutrino Physics Research
- Planetary Science and Exploration
- Spectroscopy and Laser Applications
- Molecular Spectroscopy and Structure
- Computational Physics and Python Applications
Search for Extraterrestrial Intelligence
2019-2024
Ames Research Center
2015-2021
Bay Area Environmental Research Institute
2018-2021
California Institute of Technology
2005-2018
Infrared Processing and Analysis Center
2014
Association of Universities For Research In Astronomy
2010
Center for Astrophysics Harvard & Smithsonian
2009
Carnegie Institution for Science
2009
Vanderbilt University
2009
Institut de Planétologie et d'Astrophysique de Grenoble
2009
We present the Coordinated Synoptic Investigation of NGC 2264, a continuous 30-day multi-wavelength photometric monitoring campaign on more than 1000 young cluster members using 16 telescopes. The unprecedented combination multi-wavelength, high-precision, high-cadence, and long-duration data opens new window into time domain behavior stellar objects. Here we provide an overview observations, focusing results from Spitzer CoRoT. highlight this work is detailed analysis 162 classical T Tauri...
ABSTRACT Young (125 Myr), populous (>1000 members), and relatively nearby, the Pleiades has provided an anchor for stellar angular momentum models both younger older stars. We used K 2 to explore distribution of rotation periods in Pleiades. With more than 500 new members, we are vastly expanding number with periods, particularly at low-mass end. About 92% members our sample have least one measured spot-modulated period. For ∼8% without non-astrophysical effects often dominate...
Context. The accretion process has a central role in the formation of stars and planets.
Based on more than four weeks of continuous high cadence photometric monitoring several hundred members the young cluster NGC 2264 with two space telescopes, NASA's Spitzer and CNES CoRoT (Convection, Rotation, planetary Transits), we provide quality, multi-wavelength light curves for stellar objects (YSOs) whose optical variability is dominated by short duration flux bursts, which infer are due to enhanced mass accretion rates. These show many brief -- hour one day brightenings at...
Recent measurements of rotation periods ($P_\text{rot}$) in the benchmark open clusters Praesepe (670 Myr), NGC 6811 (1 Gyr), and 752 (1.4 Gyr) demonstrate that, after converging onto a tight sequence slowly rotating stars mass$-$period space, temporarily stop spinning down. These data also show that duration this epoch stalled spin-down increases toward lower masses. To determine when resume down, we use from $K2$ mission Palomar Transient Factory to measure $P_\text{rot}$ for 58 dwarf...
ABSTRACT As the closest open cluster to Sun, Hyades is an important benchmark for many stellar properties, but its members are also scattered widely over sky. Previous studies of rotation in relied on targeted observations single stars or data from shallower all-sky variability surveys. The re-purposed Kepler mission, K2 , first opportunity measure periods ( P rot ) Hyads simultaneously while being sensitive fully convective M dwarf members. We analyze 65 and present values 48. Thirty-seven...
Abstract The Upper Scorpius OB association is the nearest region of recent massive star formation and thus an important benchmark for investigations concerning stellar evolution planet timescales. We present nine eclipsing binaries (EBs) in Scorpius, three which are newly reported here all were discovered from K2 photometry. Joint fitting eclipse photometry radial velocities acquired Keck I/HIRES spectra yields precise masses radii those systems that spectroscopically double-lined. binary...
We report the detection of V1298 Tau b, a warm Jupiter-sized planet ($R_P$ = 0.91 $\pm$ 0.05~ $R_\mathrm{Jup}$, $P 24.1$ days) transiting young solar analog with an estimated age 23 million years. The star and its belong to Group 29, association in foreground Taurus-Auriga star-forming region. While hot Jupiters have been previously reported around stars, those planets are non-transiting near-term atmospheric characterization is not feasible. system compelling target for follow-up study...
The YSOVAR (Young Stellar Object VARiability) Spitzer Space Telescope observing program obtained the first extensive mid-infrared (3.6 & 4.5 um) time-series photometry of Orion Nebula Cluster plus smaller footprints in eleven other star-forming cores (AFGL490, NGC1333, MonR2, GGD 12-15, NGC2264, L1688, Serpens Main, South, IRAS 20050+2720, IC1396A, and Ceph C). There are ~29,000 unique objects with light curves either or both IRAC channels data set. We present collection reduction for...
We present high-precision photometry on 107 variable low-mass stars and brown dwarfs in the ~3 Myr Sigma Orionis open cluster. have carried out I-band photometric monitoring within two fields, encompassing 153 confirmed or candidate members of cluster population, from 0.02 to 0.5 M_\odot. are sensitive brightness changes time scales 10 minutes weeks with amplitudes as low 0.004 magnitudes, find variability these nearly 70% members. identify both periodic aperiodic modes variability, well...
We present the discovery that UScoCTIO 5, a known spectroscopic binary in Upper Scorpius star-forming region (P = 34 days, ), is an eclipsing system with both primary and secondary eclipses apparent K2 light curves obtained during Campaign 2. have simultaneously fit eclipse profiles from existing RV data to demonstrate 5 consists of pair nearly identical M4.5 stars , . The radii are broadly consistent pre-main-sequence ages predicted by stellar evolutionary models, but none agree within...
Abstract We present an ongoing, five-year systematic search for extragalactic infrared transients, dubbed SPIRITS—SPitzer InfraRed Intensive Transients Survey. In the first year, using Spitzer /IRAC, we searched 190 nearby galaxies with cadence baselines of one month and six months. discovered over 1958 variables 43 transients. Here, describe survey design highlight 14 unusual transients no optical counterparts to deep limits, which refer as SPRITEs (eSPecially Red Intermediate-luminosity...
Abstract We have Fourier-analyzed 941 K2 light curves (LCs) of likely members Praesepe, measuring periods for 86% and increasing the number rotation ( P ) by nearly a factor four. The distribution versus <?CDATA $(V-{K}_{{\rm{s}}})$?> , mass proxy, has three different regimes: < 1.3, where rate rapidly slows as decreases; 1.3 4.5, more gradually > increases decreases. In this last regime, there is bimodal periods, with few between ∼2 ∼10 days. interpret to mean that once M stars start...
Context. The classical T Tauri star (CTTS) AA Tau has presented photometric variability that was attributed to an inner disk warp, caused by the interaction between and inclined magnetosphere. Previous studies of young cluster NGC 2264 have shown similar behavior is common among CTTS.
On 2018 Feb. 4.41, the All-Sky Automated Survey for SuperNovae (ASAS-SN) discovered ASASSN-18bt in K2 Campaign 16 field. With a redshift of z=0.01098 and peak apparent magnitude B_{max}=14.31, is nearest brightest SNe Ia yet observed by Kepler spacecraft. Here we present discovery ASASSN-18bt, light curve, pre-discovery data from ASAS-SN Asteroid Terrestrial-impact Last Alert System (ATLAS). The early-time curve has an unprecedented 30-minute cadence photometric precision SN~Ia it...
ABSTRACT We use K 2 to continue the exploration of distribution rotation periods in Pleiades that we began Paper I. have discovered complicated multiperiod behavior stars using these data, and grouped them into categories, which are focal part this paper. About 24% sample has multiple, real frequencies periodogram, sometimes manifesting as obvious beating LCs. Those having complex and/or structured periodogram peaks, unresolved multiple periods, resolved close likely due spot/spot group...
We report the discovery of three low-mass double-lined eclipsing binaries in pre-main sequence Upper Scorpius association, revealed by $K2$ photometric monitoring region over $\sim$ 78 days. The orbital periods all systems are $
We report the discovery of a repeating photometric signal from low-mass member Praesepe open cluster that we interpret as Neptune-sized transiting planet. The star is JS 183 (HSHJ 163, EPIC 211916756) with $T_{\rm eff} = 3325\pm100$ K, $M_{*} 0.44\pm0.04$ $M_{\odot}$, $R_{*} 0.44\pm0.03$ $R_{\odot}$, and $\log{g_*} 4.82\pm0.06$. planet has an orbital period 10.134588 days radius $R_{P}= 0.32\pm0.02$ $R_J$. Since faint at $V=16.5$ $J=13.3$, are unable to obtain measured radial-velocity orbit,...
We identify nine young stellar objects (YSOs) in the NGC 2264 star-forming region with optical CoRoT light curves exhibiting short-duration, shallow periodic flux dips. All of these stars have infrared excesses that are consistent their having inner disk walls near Keplerian co-rotation radius. The repeating photometric dips FWHMs generally less than 1 day, depths almost always 15%, and periods (3 < P 11 days) dust period. vary considerably depth from epoch to epoch, but usually persist for...
We present the results of optical, near-infrared, and mid-infrared observations M101 OT2015-1 (PSN J14021678+5426205), a luminous red transient in Pinwheel galaxy (M101), spanning total 16 years. The lightcurve showed two distinct peaks with absolute magnitudes $M_r\leq-12.4$ $M_r \simeq-12$, on 2014 November 11 2015 February 17, respectively. spectral energy distributions during second maximum show cool outburst temperature $\approx$3700 K low expansion velocities ($\approx-$300 \kms) for H...
We present the discovery in Kepler's $K2$ mission observations and our follow-up radial velocity from Keck/HIRES for four eclipsing binary (EB) star systems young benchmark Pleiades cluster. Based on modeling results, we announce two new low mass ($M_{tot} < 0.6 M_\odot$) EBs among members (HCG 76 MHO 9) report previously known binaries that are also found to be EB (HII 2407 HD 23642). measured masses of HCG $\lesssim$2.5% precision, radii $\lesssim$4.5% which together with precise effective...
We present an analysis of K2 light curves (LCs) for candidate members the young Upper Sco (USco) association $\sim$8 Myr) and neighboring Rho Oph embedded cluster ($\sim$1 Myr). establish $\sim$1300 stars as probable members, $\sim$80\% which are periodic. The phased LCs have a variety shapes can be attributed to physical causes ranging from stellar pulsation rotation disk-related phenomena. identify discuss number observed behaviors. periods $\sim$0.2-30 days with peak near 2 rapid period...
We present a systematic study of mid-infrared (mid-IR) emission from 141 nearby supernovae (SNe) observed with the InfraRed Array Camera (IRAC) on Spitzer.These SNe reside in one 190 galaxies within 20 Mpc drawn ongoing SPIRITS program. detect 8 Type Ia and 36 core-collapse SNe. All I become undetectable 3 years explosion. About 22$\pm$11% II continue to be detected at late-times. Dust luminosity, temperature, lower liit mass are obtained by fitting SED using photometry IRAC bands 1 2. The...