Search Publications
Successive Coronal Mass Ejections Associated with Weak Solar Energetic Particle Events
Lugaz, Noé; Zhuang, Bin; Gou, Tingyu +1 more
The scenario of twin coronal mass ejections (CMEs), i.e., a fast and wide primary CME (priCME) preceded by preceding CMEs (preCMEs), has been found to be favorable to a more efficient particle acceleration in large solar energetic particle (SEP) events. Here we study 19 events during 2007-2014 associated with twin-CME eruptions but without large S…
Revealing Ionization Conditions of Sz 102 with Spatially Resolved [Ne III] Microjets
Herczeg, Gregory J.; Liu, Chun-Fan; Shang, Hsien +1 more
Forbidden neon emission lines from small-scale microjets can probe high-energy processes in low-mass young stellar systems. We obtained spatially resolved [Ne III] spectra in the microjets from the classical T Tauri Star Sz 102 using the Hubble Space Telescope Imaging Spectrograph at a spatial resolution of ∼0"1. The blueshifted and redshifted [Ne…
The G 305 Star-forming Region. II. Irregular Variable Stars
Bayo, A.; Kounkel, Marina; Minniti, Dante +11 more
We present a catalog of 167 newly discovered, irregular variables spanning a ~7 deg2 area that encompasses the G 305 star-forming complex, one of the most luminous giant H II regions in the Galaxy. We aim to unveil and characterize the young stellar object (YSO) population of the region by analyzing the Ks-band variability an…
Planck Galactic Cold Clumps at High Galactic Latitude-a Study with CO Lines
Kim, Gwanjeong; Lee, Chin-Fei; Lee, Jeong-Eun +28 more
Gas at high Galactic latitude is a relatively little noticed component of the interstellar medium. In an effort to address this, 41 Planck Galactic Cold Clumps at high Galactic latitude (HGal; ∣b∣ > 25°) were observed in 12CO, 13CO, and C18O J = 1-0 lines, using the Purple Mountain Observatory 13.7 m telescope. …
In the Trenches of the Solar-stellar Connection. V. High-resolution Ultraviolet and X-Ray Observations of Sun-like Stars: The Curious Case of Procyon
Ayres, Thomas R.
A joint X-ray (0.2-2 keV) and ultraviolet (1150-3000 Å) time-domain study has been carried out on three nearby bright late-type stars, bracketing the Sun in properties. Alpha Cen A (HD 128620: G2 V) is a near twin to the Sun, although slightly more massive and luminous, slightly metal-rich, but older. Alpha Cen B (HD 128621: K1 V) is cooler than t…
Saddle-shaped Solar Flare Arcades
Aulanier, Guillaume; Dudík, Jaroslav; Lörinčík, Juraj
Arcades of flare loops form as a consequence of magnetic reconnection powering solar flares and eruptions. We analyze the morphology and evolution of flare arcades that formed during five well-known eruptive flares. We show that the arcades have a common saddle-like shape. The saddles occur despite the fact that the flares were of different classe…
Water Production Rate of C/2020 F3 (NEOWISE) from SOHO/SWAN over Its Active Apparition
Bertaux, J. -L.; Combi, M. R.; Quémerais, E. +2 more
C/2020 F3 (NEOWISE) was discovered in images from the Near Earth Object program of the Wide-Field Infrared Survey Explorer (NEOWISE) taken on 2020 March 27 and has become the Great Comet of 2020. The Solar Wind ANisotropies (SWAN) camera on the Solar and Heliospheric Observatory (SOHO) spacecraft, located in a halo orbit around the Earth-Sun L1 La…
Correlation of the Sunspot Number and the Waiting-time Distribution of Solar Flares, Coronal Mass Ejections, and Solar Wind Switchback Events Observed with the Parker Solar Probe
Dudok de Wit, Thierry; Aschwanden, Markus J.
Waiting-time distributions of solar flares and coronal mass ejections (CMEs) exhibit power-law-like distribution functions with slopes in the range of ατ ≈ 1.4-3.2, as observed in annual data sets during four solar cycles (1974-2012). We find a close correlation between the waiting-time power-law slope ατ and the sunspot numb…
Shock-wave Radio Probing of Solar Wind Sources in Coronal Magnetic Fields
Koval, Artem; Stanislavsky, Aleksander; Wang, Bing +3 more
The space weather effects in the near-Earth environment as well as in atmospheres of other terrestrial planets arise by corpuscular radiation from the Sun, known as the solar wind. The solar magnetic fields govern the solar corona structure. Magnetic-field strength values in the solar wind sources-key information for modeling and forecasting the s…
Ultrafaint [C II] Emission in a Redshift = 2 Gravitationally Lensed Metal-poor Dwarf Galaxy
Walter, F.; van der Wel, A.; Groves, B. +13 more
Extreme emission-line galaxies (EELGs) at redshift z = 1-2 provide a unique view of metal-poor, starburst sources that are the likely drivers of the cosmic reionization at z ≥ 6. However, the molecular gas reservoirs of EELGs—the fuel for their intense star formation—remain beyond the reach of current facilities. We present ALMA [C II] and PdBI CO…