Search Publications
GW Ori: Interactions between a Triple-star System and Its Circumtriple Disk in Action
Dong, Ruobing; Kataoka, Akimasa; Takami, Michihiro +17 more
GW Ori is a hierarchical triple system with a rare circumtriple disk. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of 1.3 mm dust continuum and 12CO J = 2 - 1 molecular gas emission of the disk. For the first time, we identify three dust rings in the GW Ori disk at ∼46, 188, and 338 au, with estimated dust…
Detection and Characterization of Oscillating Red Giants: First Results from the TESS Satellite
Barclay, Thomas; Chaplin, William J.; Davies, Guy R. +78 more
Since the onset of the "space revolution" of high-precision high-cadence photometry, asteroseismology has been demonstrated as a powerful tool for informing Galactic archeology investigations. The launch of the NASA Transiting Exoplanet Survey Satellite (TESS) mission has enabled seismic-based inferences to go full sky—providing a clear advantage …
Emergence of an Ultrared, Ultramassive Galaxy Cluster Core at z = 4
Ivison, R. J.; Casey, Caitlin M.; Long, Arianna S. +6 more
Recent simulations and observations of massive galaxy cluster evolution predict that the majority of stellar mass buildup happens within cluster members by z = 2, before cluster virialization. Protoclusters rich with dusty, star-forming galaxies (DSFGs) at z > 3 are the favored candidate progenitors for these massive galaxy clusters at z ∼ 0. W…
Peter Pan Disks: Long-lived Accretion Disks Around Young M Stars
Debes, John H.; Kuchner, Marc J.; Wisniewski, John P. +11 more
WISEA J080822.18-644357.3, an M star in the Carina association, exhibits extreme infrared excess and accretion activity at an age greater than the expected accretion disk lifetime. We consider J0808 as the prototypical example of a class of M star accretion disks at ages ≳20 Myr, which we call "Peter Pan" disks, because they apparently refuse to g…
Sun-Heliosphere Observation-based Ionization Rates Model
McComas, D. J.; Bzowski, M.; Tokumaru, M. +1 more
The solar wind (SW) and the extreme ultraviolet (EUV) radiation modulate fluxes of interstellar and heliospheric particles inside the heliosphere both in time and in space. Understanding this modulation is necessary to correctly interpret measurements of particles of interstellar origin inside the heliosphere. We present a revision of heliospheric…
Ion-neutral Interactions and Nonequilibrium Ionization in the Solar Chromosphere
Martínez-Sykora, Juan; De Pontieu, Bart; Nóbrega-Siverio, Daniel +4 more
The thermal structure of the chromosphere is regulated through a complex interaction of various heating processes, radiative cooling, and the ionization degree of the plasma. Here, we study the impact on the thermal properties of the chromosphere when including the combined action of nonequilibrium ionization (NEI) of hydrogen and helium and ion-n…
Spatially Resolved Ultraviolet Spectroscopy of the Great Dimming of Betelgeuse
Dupree, Andrea K.; Guinan, Edward F.; Leike, Reimar +9 more
The bright supergiant Betelgeuse (Alpha Orionis, HD 39801) experienced a visual dimming during 2019 December and the first quarter of 2020, reaching an historic minimum 2020 February 7-13. During 2019 September-November, prior to the optical dimming event, the photosphere was expanding. At the same time, spatially resolved ultraviolet spectra usin…
An Unbiased ALMA Spectral Survey of the LkCa 15 and MWC 480 Protoplanetary Disks
Wilner, David J.; Cleeves, L. Ilsedore; Walsh, Catherine +13 more
The volatile contents of protoplanetary disks both set the potential for planetary chemistry and provide valuable probes of defining disk system characteristics such as stellar mass, gas mass, ionization, and temperature structure. Current disk molecular inventories are fragmented, however, giving an incomplete picture: unbiased spectral line surv…
A Panoramic Landscape of the Sagittarius Stream in Gaia DR2 Revealed with the STREAMFINDER Spyglass
Martin, Nicolas; Malhan, Khyati; Siebert, Arnaud +4 more
We present the first full six-dimensional panoramic portrait of the Sagittarius stream, obtained by searching for wide stellar streams in the Gaia DR2 data set with the STREAMFINDER algorithm. We use the kinematic behavior of the sample to devise a selection of Gaia RR Lyrae, providing excellent distance measurements along the stream. The proper m…
A Joint Mass-Radius-Period Distribution of Exoplanets
Rogers, Leslie A.; Neil, Andrew R.
The radius-period distribution of exoplanets has been characterized by the Kepler survey, and the empirical mass-radius relation by the subset of Kepler planets with mass measurements. We combine the two in order to constrain the joint mass-radius-period distribution of Kepler transiting planets. We employ hierarchical Bayesian modeling and mixtur…