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Time evolution of gaps in stellar streams in axisymmetric Stäckel potentials
Helmi, Amina; Koppelman, Helmer H.
Context. When a subhalo interacts with a cold stellar stream, the otherwise nearly smooth distribution of stars is disturbed, and this creates a gap. The properties of these gaps depend on the interaction parameters. Their characterisation could thus lead to a determination of the mass spectrum of the perturbers and might reveal the existence of d…
The key impact of the host star's rotational history on the evolution of TOI-849b
Buldgen, G.; Eggenberger, P.; Bourrier, V. +2 more
Context. TOI-849b is one of the few planets populating the hot-Neptune desert and it is the densest Neptune-sized one discovered so far. Its extraordinary proximity to the host star, together with the absence of a massive H/He envelope on top of the 40.8 M⊕ rocky core, calls into question the role played by the host star in the evolutio…
Filament Eruption Driving EUV Loop Contraction and Then Expansion above a Stable Filament
Schmieder, Brigitte; Joshi, Reetika; Chandra, Ramesh +2 more
We analyze the observations of EUV loop evolution associated with the filament eruption located at the border of an active region (AR). The event SOL2013-03-16T14:00 was observed with a large difference in view point by the Solar Dynamics Observatory and Solar Terrestrial Relations Observatory. The filament height is fitted with the sum of a linea…
DIISC-I: The Discovery of Kinematically Anomalous H I Clouds in M 100
Heckman, Timothy M.; Nelson, Dylan; Thilker, David +10 more
We report the discovery of two kinematically anomalous atomic hydrogen (H I) clouds in M 100 (NGC 4321), which was observed as part of the Deciphering the Interplay between the Interstellar medium, Stars, and the Circumgalactic medium (DIISC) survey in H I 21 cm at 3.3 km s-1 spectroscopic and 44″ × 30″ spatial resolution using the Karl…
The Effect of the Morphological Quenching Mechanism on Star Formation Activity at 0.5 < z < 1.5 in 3D-HST/CANDELS
Fang, Guanwen; Kong, Xu; Gu, Yizhou +3 more
Several mechanisms for the transformation of blue star-forming to red quiescent galaxies have been proposed, and the green valley (GV) galaxies amid them are widely accepted in a transitional phase. Thus, comparing the morphological and environmental differences of the GV galaxies with early-type disks (ETDs; bulge dominated and having a disk) and…
Mysterious Dust-emitting Object Orbiting TIC 400799224
Kostov, Veselin B.; Powell, Brian P.; Rappaport, Saul A. +24 more
We report the discovery of a unique object of uncertain nature-but quite possibly a disintegrating asteroid or minor planet-orbiting one star of the widely separated binary TIC 400799224. We initially identified the system in data from TESS Sector 10 via an abnormally shaped fading event in the light curve (hereafter "dips"). Follow-up speckle ima…
Possible Evidence of Hydrogen Emission in the First-overtone and Multimode RR Lyrae Variables
Deng, Li-Cai; Liu, Chao; Zhang, Hua-Wei +4 more
The nature of shock waves in nonfundamental mode RR Lyrae stars remains a mystery because of limited spectroscopic observations. We apply a pattern recognition algorithm on spectroscopic data from SDSS and LAMOST and report the first evidence of hydrogen emission in first-overtone (RRc) and multimode (RRd) RR Lyrae stars showing the "first apparit…
Precise diffusion coefficients for white dwarf astrophysics
Caplan, M. E.; Freeman, I. F.
Observations of Galactic white dwarfs with Gaia have allowed for unprecedented modelling of white dwarf cooling, resolving core crystallization, and sedimentary heating from neutron-rich nuclei. These cooling sequences are sensitive to the diffusion coefficients of nuclei in Coulomb plasmas which have order 10 per cent uncertainty and are often no…
The Missing Link? Discovery of Pulsations in the Nitrogen-rich PG 1159 Star PG 1144+005
Jones, David; Handler, Gerald; Sowicka, Paulina +1 more
Up to 98% of all single stars will eventually become white dwarfs-stars that link the history and future evolution of the Galaxy, and whose previous evolution is engraved in their interiors. Those interiors can be studied using asteroseismology, utilizing stellar pulsations as seismic waves. The pulsational instability strips of DA and DB white dw…
X-Ray Constraints on the Hot Gas Content of Early-type Galaxies in Virgo
Jones, Christine; Li, Zhiyuan; Hou, Meicun +2 more
We present a systematic study of the diffuse hot gas around early-type galaxies (ETGs) residing in the Virgo cluster, based on archival Chandra observations. Our representative sample consists of 79 galaxies with low-to-intermediate stellar masses (M* ≈ 109-11 M⊙), a mass range that has not been extensively explore…