Search Publications
Dynamical and Atmospheric Characterization of the Substellar Companion HD 33632 Ab from Direct Imaging, Astrometry, and Radial-velocity Data
Currie, Thayne; Tamura, Motohide; Kuzuhara, Masayuki +17 more
We present follow-up SCExAO/CHARIS H- and K-band (R ∼ 70) high-contrast integral field spectroscopy and Keck/NIRC2 photometry of directly imaged brown dwarf companion HD 33632 Ab and new radial-velocity data for the system from the SOPHIE spectrograph, complemented by Hipparcos and Gaia astrometry. These data enable more robust spectral characteri…
Differentiating the Acceleration Mechanisms in the Slow and Alfvénic Slow Solar Wind
D'Amicis, Raffaella; Reeves, Katharine K.; Stawarz, Julia E. +18 more
In the corona, plasma is accelerated to hundreds of kilometers per second and heated to temperatures hundreds of times hotter than the Sun's surface before it escapes to form the solar wind. Decades of space-based experiments have shown that the energization process does not stop after it escapes. Instead, the solar wind continues to accelerate, a…
The Blue Lurker WOCS 14020: A Long-period Post-common-envelope Binary in M67 Originating from a Merger in a Triple System
Sills, Alison; Sun, Meng; Mathieu, Robert D. +3 more
We present Hubble Space Telescope far-ultraviolet (FUV) spectra of a blue lurker–white dwarf (BL–WD) binary system in the 4 Gyr open cluster M67. We fit the FUV spectrum of the WD, determining it is a C/O WD with a mass of
C3PO. III. On the Lithium Signatures following Planet Engulfment by Stars
Ting, Yuan-Sen; Twarog, Bruce A.; Anthony-Twarog, Barbara J. +8 more
Planet engulfment has been identified as one of the mechanisms for enhancing lithium abundance in stars. However, comprehensive investigations into lithium signatures following such events remain limited. Stars born together, sharing a common origin and stellar characteristics, provide a unique opportunity to study these signatures and compare lit…
Imaging and Spectral Fitting of Bright Gamma-Ray Sources with the COSI Balloon Payload
Yoneda, Hiroki; Tomsick, John A.; Cangemi, Floriane +17 more
The Compton Spectrometer and Imager balloon payload (COSI-Balloon) is a wide field-of-view Compton gamma-ray telescope that operates in the 0.2–5 MeV bandpass. COSI-Balloon had a successful 46 day flight in 2016 during which the instrument observed the Crab Nebula, Cygnus X-1, and Centaurus A. Using the data collected by the COSI-Balloon instrumen…
Cataloging Stream Interaction Regions at MAVEN: A Cross-comparative Study with STEREO-A
Allen, Robert C.; Lee, Christina O.; Halekas, Jasper S. +5 more
Stream interaction regions (SIRs) are long-lasting solar wind structures that result from stable fast solar wind interacting with preceding slow solar wind. These structures have been examined in depth throughout the heliosphere, particularly at 1 au; however, due to sparse observations, SIRs have not been characterized thoroughly at 1.5 au. Thank…
Evolution of X-Ray Gas in SN 1987A from 2007 to 2021: Ring Fading and Ejecta Brightening Unveiled through Differential Emission Measure Analysis
Greco, Emanuele; Vink, Jacco; Miceli, Marco +4 more
As the nearest supernova (SN) observed since Kepler's SN of 1604, SN 1987A provides an unprecedented opportunity to study in detail the early evolution of supernova remnants. Despite extensive studies through both observations and simulations, there is still an urgent need for a more effective approach to integrate the results from two sides. In t…
LEIA Discovery of the Longest-lasting and Most Energetic Stellar X-Ray Flare Ever Detected
Shi, Jianrong; Lin, Jun; Deng, Licai +40 more
The Lobster Eye Imager for Astronomy (LEIA) detected a new X-ray transient on 2022 November 7, identified as a superflare event occurring on a nearby K-type giant star HD 251108. The flux increase was also detected in follow-up observations at X-ray, UV, and optical wavelengths. The flare lasted for about 40 days in soft X-ray observations, reachi…
Ion Charge States from a Global Time-dependent Wave-turbulence-driven Model of the Solar Wind: Comparison with in Situ Measurements
Riley, Pete; Rivera, Yeimy J.; Lionello, Roberto
Solar wind charge-state measurements contain a wealth of knowledge related to the properties of the solar corona from where they originated. However, their interpretation has remained challenging because it convolves coronal temperature, density, and velocity along the particles' trajectory through the corona before they "freeze in" and are convec…
Disk-locking Regulates Stellar Rotation in Young Clusters: Insights from NGC 2264
Fang, Min; Li, Chengyuan; Bu, Yutian +1 more
Many young clusters possess extended main sequences, a phenomenon commonly ascribed to stellar rotation. However, the mechanism behind their very wide stellar rotation distributions remains unclear. A proposed explanation is that magnetic star–disk interaction can regulate stellar rotation, i.e., protostars with longer disk lifetimes will eventual…