Search Publications
The Nitrogen Carrier in Inner Protoplanetary Disks
Banzatti, Andrea; Walsh, Catherine; Pontoppidan, Klaus M. +4 more
The dominant reservoirs of elemental nitrogen in protoplanetary disks have not yet been observationally identified. Likely candidates are HCN, NH3, and N2. The relative abundances of these carriers determine the composition of planetesimals as a function of disk radius due to strong differences in their volatility. A signific…
Spherical models of star clusters with potential escapers
Varri, Anna Lisa; Heggie, Douglas C.; Gieles, Mark +2 more
An increasing number of observations of the outer regions of globular clusters (GCs) have shown a flattening of the velocity dispersion profile and an extended surface density profile. Formation scenarios of GCs can lead to different explanations of these peculiarities, therefore the dynamics of stars in the outskirts of GCs are an important tool …
Kinetic Energy Transfer from X-Ray Ultrafast Outflows to Millimeter/Submillimeter Cold Molecular Outflows in Seyfert Galaxies
Kohno, Kotaro; Mizumoto, Misaki; Izumi, Takuma
UltraFast Outflows (UFOs), seen as X-ray blueshifted absorption lines in active galactic nuclei (AGNs), are considered to be a key mechanism for AGN feedback. In this scenario, UFO kinetic energy is transferred into the cold and extended molecular outflow observed at the millimeter/submillimeter wavelength, which blows away the gas and suppresses …
K2 Ultracool Dwarfs Survey - V. High superflare rates on rapidly rotating late-M dwarfs
Mullan, D. J.; Burgasser, A. J.; Stassun, K. G. +5 more
We observed strong superflares (defined as flares with energy in excess of 1033 erg) on three late-M dwarfs: 2MASS J08315742+2042213 (hereafter 2M0831+2042; M7 V), 2MASS J08371832+2050349 (hereafter 2M0837+2050; M8 V), and 2MASS J08312608+2244586 (hereafter 2M0831+2244; M9 V). 2M0831+2042 and 2M0837+2050 are members of the young (∼700 M…
KELT-24b: A 5M J Planet on a 5.6 day Well-aligned Orbit around the Young V = 8.3 F-star HD 93148
Cargile, Phillip A.; Bieryla, Allyson; Latham, David W. +76 more
We present the discovery of KELT-24 b, a massive hot Jupiter orbiting a bright (V = 8.3 mag, K = 7.2 mag) young F-star with a period of 5.6 days. The host star, KELT-24 (HD 93148), has a T eff = {6509}-49+50 K, a mass of M * = {1.460}-0.059+0.055 M ⊙, a radius of R *…
The Green Bank Ammonia Survey: A Virial Analysis of Gould Belt Clouds in Data Release 1
Caselli, Paola; Chen, Mike; Di Francesco, James +14 more
We perform a virial analysis of starless dense cores in three nearby star-forming regions: L1688 in Ophiuchus, NGC 1333 in Perseus, and B18 in Taurus. Our analysis takes advantage of comprehensive kinematic information for the dense gas in all of these regions made publicly available through the Green Bank Ammonia Survey Data Release 1, which is u…
Large-amplitude Quasiperiodic Pulsations as Evidence of Impulsive Heating in Hot Transient Loop Systems Detected in the EUV with SDO/AIA
Testa, Paola; Petralia, Antonino; Reale, Fabio +1 more
Short heat pulses can trigger plasma pressure fronts inside closed magnetic tubes in the corona. The alternation of condensations and rarefactions from the pressure modes drive large-amplitude pulsations in the plasma emission. Here we show the detection of such pulsations along magnetic tubes that brighten transiently in the hot 94 Å EUV channel …
Dusk over dawn O2 asymmetry in Europa's near-surface atmosphere
Johnson, Robert E.; Chaufray, Jean-Yves; Oza, Apurva V. +4 more
The evolution of Europa's water-product exosphere over its 85-h day, based on current models, has not been shown to exhibit any diurnal asymmetries. Here we simulate Europa's exosphere using a 3-D Monte Carlo routine including, for the first time, the role of Europa's rotation on the evolution of exospheric molecules tracked throughout the orbit. …
How Comets Work
Blum, J.; Fulle, M.; Rotundi, A.
Two major questions regarding comets have been up to now far from any solution. (i) How is it possible that water-ice sublimation from the nucleus surface does not lead to an insulating crust, stopping every gas and dust ejection within a few days? (ii) How is it possible that the gas flow crossing the refractory surface crust ejects dust particle…
Orbital Motion of the Wide Planetary-mass Companion GSC 6214-210 b: No Evidence for Dynamical Scattering
Rizzuto, Aaron C.; Dupuy, Trent J.; Ireland, Michael J. +5 more
Direct-imaging exoplanet surveys have discovered a class of 5-20 {M}Jup} substellar companions at separations >100 au from their host stars, which present a challenge to planet and star formation models. Detailed analysis of the orbital architecture of these systems can provide constraints on possible formation mechanisms, including …