Search Publications
Solar Wind Helium Abundance Heralds Solar Cycle Onset
McIntosh, Scott W.; Kasper, Justin C.; Leamon, Robert J. +1 more
We study the solar wind helium-to-hydrogen abundance's (AHe) relationship to solar cycle onset. Using OMNI/Lo data, we show that AHe increases prior to sunspot number (SSN) minima. We also identify a rapid depletion and recovery in AHe that occurs directly prior to cycle onset. This AHe shutoff happens a…
The Lithium Abundances from the Large Sky Area Multi-object Fiber Spectroscopic Telescope Medium-resolution Survey. I. The Method
Zhang, Yong; Gao, Qi; Yan, Hong-Liang +9 more
One of the purposes of taking spectra for millions of stars through the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) medium-resolution survey (MRS) is to obtain the elemental abundances, so that one can trace the origin and evolution for the element of interests. Lithium is one of such elements of great importance, which exhi…
Oscillations and Mass Draining that Lead to a Sympathetic Eruption of a Quiescent Filament
Xu, Zhe; Zhang, Qingmin; Zhang, Yanjie +3 more
In this paper, we present a multiwavelength analysis to mass draining and oscillations in a large quiescent filament prior to its successful eruption on 2015 April 28. The eruption of a smaller filament that was parallel and in close, ~350″ proximity was observed to induce longitudinal oscillations and enhance mass draining within the filament of …
Binary Fractions of G and K Dwarf Stars Based on Gaia EDR3 and LAMOST DR5: Impacts of the Chemical Abundances
Niu, Zexi; Liu, Jifeng; Wang, Song +1 more
Based on the large volume Gaia Early Data Release 3 and LAMOST Data Release 5 data, we estimate the bias-corrected binary fractions of the field late G and early K dwarfs. A stellar locus outlier method is used in this work, which works well for binaries of various periods and inclination angles with single-epoch data. With a well-selected, distan…
Higher Compact Multiple Occurrence around Metal-poor M-dwarfs and Late-K-dwarfs
Bedell, Megan; Dittmann, Jason A.; Ballard, Sarah +1 more
The planet-metallicity correlation serves as a potential link between exoplanet systems as we observe them today and the effects of bulk composition on the planet formation process. Many observers have noted a tendency for Jovian planets to form around stars with higher metallicities; however, there is no consensus on a trend for smaller planets. …
Regulating Star Formation in Nearby Dusty Galaxies: Low Photoelectric Efficiencies in the Most Compact Systems
Inami, H.; Pope, A.; Armus, L. +5 more
Star formation in galaxies is regulated by heating and cooling in the interstellar medium (ISM). In particular, the processing of molecular gas into stars will depend strongly on the ratio of gas heating to gas cooling in the neutral gas around sites of recent star formation. In this work, we combine mid-infrared (mid-IR) observations of polycycli…
The first interferometric survey of massive YSOs in the K-band. Hot dust, ionised gas, and binarity at au scales
Mendigutía, I.; Stecklum, B.; de Wit, W. -J. +8 more
Context. Circumstellar discs are essential for the formation of high mass stars, while multiplicity, and in particular binarity, appears to be an inevitable outcome, as the vast majority of massive stars (>8 M⊙) are found in binaries (up to 100%). Our understanding of the innermost regions of accretion discs around massive stars and …
Predictions of Astrometric Jitter for Sun-like Stars. II. Dependence on Inclination, Metallicity, and Active-region Nesting
Solanki, S. K.; Shapiro, A. I.; Mints, A. +5 more
Ultra-precise astrometry from the Gaia mission is expected to lead to astrometric detections of more than 20,000 exoplanets in our Galaxy. One of the factors that could hamper such detections is the astrometric jitter caused by the magnetic activity of the planet host stars. In our previous study, we modeled astrometric jitter for the Sun observed…
First Detection and Thermal Characterization of Terminator CO2 Ice Clouds With ExoMars/NOMAD
Vandaele, Ann Carine; Stolzenbach, Aurélien; Aoki, Shohei +16 more
We present observations of terminator CO2 ice clouds events in three groups: Equatorial dawn, Equatorial dusk (both between 20°S and 20°N) and Southern midlatitudes at dawn (45°S and 55°S east of Hellas Basin) with ESA ExoMars Trace Gas Orbiter's Nadir and Occultation for MArs Discovery instrument. CO2 ice abundance is retrie…
MUSE-ALMA haloes VI: coupling atomic, ionized, and molecular gas kinematics of galaxies
Hamanowicz, Aleksandra; Péroux, Céline; Augustin, Ramona +7 more
We present results of MUSE-ALMA haloes, an ongoing study of the circumgalactic medium (CGM) of galaxies (z ≤ 1.4). Using multiphase observations we probe the neutral, ionized, and molecular gas in a subsample containing six absorbers and nine associated galaxies in the redshift range z ~ 0.3-0.75. Here, we give an in-depth analysis of the newly CO…