Search Publications
A polarimetric study of asteroids in comet-like orbits
Watanabe, Makoto; Imai, Masataka; Kim, Yoonyoung +16 more
Context. Asteroids in comet-like orbits (ACOs) consist of asteroids and dormant comets. Due to their similar appearance, it is challenging to distinguish dormant comets from ACOs via general telescopic observations. Surveys for discriminating dormant comets from the ACO population have been conducted via spectroscopy or optical and mid-infrared ph…
Partially-Saturated Brines Within Basal Ice or Sediments Can Explain the Bright Basal Reflections in the South Polar Layered Deposits
Lauro, S. E.; Pettinelli, E.; Orosei, R. +5 more
Strong radar reflections have been previously mapped at the base of the Martian South Polar Layered Deposits. Here, we analyze laboratory measurements of dry and briny samples to determine the cause of this radar return. We find that liquid vein networks consisting of brines at the grain boundaries of ice crystals can greatly enhance the electrica…
Variations of the Internal Asymmetries of Sunspot Groups during Their Decay
Muraközy, Judit
The aim of the present study is to show the varying asymmetries during the decay of sunspot groups. The source of input data is the SOHO/MDI-Debrecen Database sunspot catalog that contains the magnetic polarity data for time interval 1996-2010. Several types of asymmetries were examined on the selected sample of 142 sunspot groups. The leading-fol…
Weather forecast of the Milky Way: shear and stellar feedback determine the lives of Galactic-scale filaments
Li, Guang-Xing; Chen, Bing-Qiu; Zhou, Ji-Xuan
The interstellar medium (ISM) is an inseparable part of the Milky Way ecosystem whose evolutionary history remains a challenging question. We trace the evolution of the molecular ISM using a sample of young stellar objects (YSO) association-molecular cloud complex (YSO-MC complex). We derive their three-dimensional (3D) velocities by combining the…
No Evolution in the Half-mass Radius of Milky Way-type Galaxies over the Last 10 Gyr
Tacchella, Sandro; Park, Minjung; Naidu, Rohan P. +3 more
The Milky Way (MW) galaxy is in focus, thanks to new observational data. Here we shed new light on the MW's past by studying the structural evolution of MW progenitors, which we identify from extragalactic surveys. Specifically, we constrain the stellar-mass growth history (SMGH) of the MW with two methods: (i) direct measurement of the MW's star …
Figures of merit for a stochastic gravitational-wave background measurement by LISA: Implications of LISA Pathfinder noise correlations
Christensen, Nelson; Meyer, Renate; Boileau, Guillaume
An important goal of the Laser Interferometer Space Antenna (LISA) is to observe a stochastic gravitational-wave background (SGWB). A study of possible correlated noise in LISA is relevant to establish limits for this future measurement. To test noise investigation methods under somewhat realistic conditions, we use the data of LISA Pathfinder. We…
Dust Evolution in the Coma of Distant, Inbound Comet C/2017 K2 (PANSTARRS)
Kolokolova, Ludmilla; Zhang, Qicheng; Ye, Quanzhi +1 more
C/2017 K2 (PANSTARRS) is an Oort Cloud comet previously observed to be active at heliocentric distances r > 20 au on what is likely its first passage through the inner solar system. We observed the comet on 2021 March 19-20 at r = 6.82 au preperihelion and 8.°35 phase angle with the Hubble Space Telescope (HST), and obtained high spatial resolu…
A survey of deuterated ammonia in the Cepheus star-forming region L1251
Di Francesco, James; Keown, Jared; Shirley, Yancy L. +4 more
Understanding the chemical processes during starless core and prestellar core evolution is an important step in understanding the initial stages of star and disc formation. This project is a study of deuterated ammonia, o-NH2D, in the L1251 star-forming region towards Cepheus. Twenty-two dense cores (20 of which are starless or prestell…
Ages of Main-sequence Turnoff Stars from the GALAH Survey
Wu, Yaqian; Chen, Yuqin; Bi, Shaolan +6 more
Main-sequence turnoff (MSTO) stars are good tracers of Galactic populations since their ages can be reliably estimated from atmospheric parameters. Based on the GALAH survey, we use the Yale rotation evolution code to determine the ages of 2926 MSTO stars with a mean age uncertainty of ~10% considering the variation of C and O abundances. The ages…
Eruption of the EUV Hot Channel from the Solar Limb and Associated Moving Type IV Radio Burst
Zhang, J.; Démoulin, P.; Gopalswamy, N. +3 more
Using the observations from the Solar Dynamics Observatory, we study an eruption of a hot-channel flux rope (FR) near the solar limb on 2015 February 9. The pre-eruptive structure is visible mainly in EUV 131 Å images, with two highly sheared loop structures. They undergo a slow rising motion and then reconnect to form an eruptive hot channel, as …