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Mid-infrared Studies of HD 113766 and HD 172555: Assessing Variability in the Terrestrial Zone of Young Exoplanetary Systems
Rieke, George H.; Gáspár, András; Meng, Huan Y. A. +4 more
We present multiepoch infrared photometry and spectroscopy obtained with warm Spitzer, Subaru, and the Stratospheric Observatory for Infrared Astronomy to assess variability for the young (∼20 Myr) and dusty debris systems around HD 172555 and HD 113766A. No variations (within 0.5%) were found for the former at either 3.6 or 4.5 µm, while si…
Simultaneous Observations of ELF/VLF Rising-Tone Quasiperiodic Waves and Energetic Electron Precipitations in the High-Latitude Upper Ionosphere
Lei, Jungang; Zhima, Zeren; Huang, Jianping +12 more
The quasiperiodic (QP) waves accompanied by simultaneous energetic electron precipitations in the high-latitude ionosphere were recorded by the sun-synchronous circular orbit China Seismo-Electromagnetic Satellite (CSES). The new features of QP waves observed by CSES are the well-pronounced rising-tone structures and very short repetition periods,…
Observations of Disintegrating Long-period Comet C/2019 Y4 (ATLAS): A Sibling of C/1844 Y1 (Great Comet)
Ye, Quan-Zhi; Hui, Man-To
We present a study of C/2019 Y4 (ATLAS) using Sloan gri observations from 2020 mid-January to early April. During this time span, the comet brightened with a growth in the effective cross-section of $\left(2.0\pm 0.1\right)\times {10}^{2}$ m2 s-1 from the beginning to ∼70 days preperihelion in late 2020 March, followed by a b…
Role of the impact parameter in exoplanet transmission spectroscopy
Strassmeier, K. G.; Mallonn, M.; von Essen, C. +3 more
Context. Transmission spectroscopy is a promising tool for the atmospheric characterization of transiting exoplanets. Because the planetary signal is faint, discrepancies have been reported regarding individual targets.
Aims: We investigate the dependence of the estimated transmission spectrum on deviations of the orbital parameters of the st…
Li-rich K giants, dust excess, and binarity
Jorissen, A.; Pourbaix, D.; Escorza, A. +3 more
The origin of the Li-rich K giants is still highly debated. Here, we investigate the incidence of binarity among this family from a nine-year radial-velocity monitoring of a sample of 11 Li-rich K giants using the HERMES spectrograph attached to the 1.2 m Mercator Telescope. A sample of 13 non-Li-rich giants (8 of them being surrounded by dust acc…
The 21 µm and 30 µm emission features in carbon-rich objects
Volk, Kevin; Sloan, G. C.; Kraemer, Kathleen E.
We review the observational properties and possible carriers of the 21 and 30 µm features seen in the spectra of evolved carbon-rich objects. The 30 µm feature is generally taken to be due to MgS, possibly in combination with other sulfides. It is commonly assumed that the sulfides coat grains of SiC or amorphous carbon, but it remains…
Analysis of the TiO isotopologues in stellar optical spectra
Yurchenko, Sergei N.; Pavlenko, Ya. V.; Tennyson, Jonathan +1 more
Context. We used the new ExoMol TiO rovibronic line lists to identify and model TiO isotopologue features in spectra of M dwarfs.
Aims: We investigate problems involving the computation of electronic bands for different isotopologues of TiO by modelling optical spectra of late-type stars. Based on this, we determine their Ti isotopic abundanc…
A Wide Planetary-mass Companion to a Young Low-mass Brown Dwarf in Ophiuchus
Albert, Loïc; Liu, Michael C.; Zhang, Zhoujian +6 more
We present the discovery of a planetary-mass companion to CFHTWIR-Oph 98, a low-mass brown dwarf member of the young Ophiuchus star-forming region, with a wide 200 au separation (1"46). The companion was identified using Hubble Space Telescope images, and confirmed to share common proper motion with the primary using archival and new ground-based …
An Analysis of the Statistics and Systematics of Limb Anomaly Detections in HST/STIS Transit Images of Europa
Strobel, Darrell; Saur, Joachim; Giono, Gabriel +5 more
Several recent studies derived the existence of plumes on Jupiter's moon Europa. The only technique that provided multiple detections is the far-ultraviolet imaging observations of Europa in transit of Jupiter taken by the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST). In this study, we reanalyze the three HST/STI…
Multiwavelength Absolute Magnitudes and Colors of Red Clump Stars in the Gaia Era
Bilir, Selçuk; Plevne, Olcay; Seabroke, George M. +1 more
This study presents the multiwavelength investigation of the absolute magnitudes and colors of the red clump (RC) stars selected from APOGEE and GALAH DR2 combined catalog which is complemented with Gaia DR2 astrometric data and multiwavelength photometric data of GALEX GR6/7, SDSS DR7, Gaia DR2, 2MASS, and WISE sky surveys. The analyses are cente…