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Be, V, and Cu in the halo star CS 31082-001 from near-UV spectroscopy
Spite, M.; Evans, C. J.; Barbuy, B. +5 more
The 'First Stars' programme revealed the metal-poor halo star CS 31082-001 to be r-process and actinide rich, including the first measurement of a uranium abundance for an old star. To better characterize and understand such rare objects, we present the first abundance estimates of three elements (Be, V, Cu) for CS 31082-001 from analysis of its n…
Decade-long time-monitoring of candidate luminous blue variable stars in the two very metal-deficient star-forming galaxies DDO 68 and PHL 293B
Thuan, T. X.; Izotov, Y. I.; Guseva, N. G.
We have studied the spectral time variations of candidate luminous blue variable (cLBV) stars in two low-metallicity star-forming galaxies, DDO 68 and PHL 293B. The LBV in DDO 68, located in H II region #3, shows an outburst, with an increase of more than 1000 times in H α luminosity during the period 2008-2010. The broad emission of the H I and H…
ALMA's view of the M-dwarf GSC 07396-00759's edge-on debris disc: AU Mic's coeval twin
Kral, Quentin; Murphy, Simon J.; Wyatt, Mark C. +7 more
We present new ALMA Band 7 observations of the edge-on debris disc around the M1V star GSC 07396-00759. At ~20 Myr old and in the β Pictoris Moving Group along with AU Mic, GSC 07396-00759 joins it in the handful of low-mass M-dwarf discs to be resolved in the sub-mm. With previous VLT/SPHERE scattered light observations, we present a multiwavelen…
KMT-2017-BLG-0673Lb and KMT-2019-BLG-0414Lb: Two microlensing planets detected in peripheral fields of KMTNet survey
Han, Cheongho; Lee, Chung-Uk; Zang, Weicheng +18 more
Aims: We investigate the microlensing data collected during the 2017-2019 seasons in the peripheral Galactic bulge fields with the aim of finding planetary signals in microlensing light curves observed with relatively sparse coverage.
Methods: We first sort out lensing events with weak short-term anomalies in the lensing light curves fro…
Probing the surface environment of large T-type asteroids
Hasegawa, Sunao; Agarwal, Jessica; Fornasier, Sonia +2 more
Context. The thermal and radiative environments encountered by asteroids have shaped their surface features. Recent observations have focused on asteroids in the main belt and showed indications for ices and organics in the interiors of the asteroids that were likely significant on prebiotic Earth. They stand out in reflectance spectra as darker, …
Migrating Dynamo Waves and Consequences for Stellar Current Sheets
Sokoloff, Dmitry; Malova, Helmi; Popov, Victor +2 more
We study the relation between stellar dynamo-wave propagation and the structure of the stellar magnetic field. Modeling dynamo waves by the well-known Parker migratory dynamo, we vary the intensity of dynamo drivers in order to obtain activity-wave propagation toward the Equator (as in the solar-activity cycle) or towards the Poles. We match the m…
Additions to the Spectrum of Fe IX in the 110-200 Å Region
Young, Peter R.; Ryabtsev, Alexander N.; Kononov, Edward Y.
The spectrum of eight-times ionized iron, Fe IX, was studied in the 110-200 Å region. A low inductance vacuum spark and a 3 m grazing incidence spectrograph were used for the excitation and recording of the spectrum. Previous analyses of Fe IX have been greatly extended and partly revised. The number of known lines in the 3p 53d-3p
Very Metal-poor Stars in the Solar Vicinity: Age Determination
Villanova, Sandro; Carraro, Giovanni; Plotnikova, Anastasiia +1 more
The ages of the oldest and most metal-poor stars in the Milky Way bear important information on the age of the universe and its standard model. We analyze a sample of 28 extremely metal-poor field stars in the solar vicinity culled from the literature and carefully determine their ages. To this aim, we critically make use of Gaia data to derive th…
X-ray emission of contact binary variables within 1 kpc
Esamdin, Ali; Gu, Wei-Min; Liu, Junhui +3 more
Aims: The X-ray emission of contact binaries (EW-type) is an important facet of such systems. Thus, X-ray emitting EW-type binaries (EWXs) are ideal laboratories for studying the X-ray radiation saturation mechanisms as well as binary evolution. By assembling the largest sample to date of EWXs with periods of less than 1 day from the All-Sky …
A Two-Spacecraft Study of Mars' Induced Magnetosphere's Response to Upstream Conditions
Edberg, Niklas J. T.; Dimmock, Andrew P.; Sánchez-Cano, Beatriz +5 more
This is a two-spacecraft study, in which we investigate the effects of the upstream solar wind conditions on the Martian induced magnetosphere and upper ionosphere. We use Mars Express (MEX) magnetic field magnitude data together with interplanetary magnetic field (IMF), solar wind density, and velocity measurements from the Mars Atmosphere and Vo…