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Typhon: A Polar Stream from the Outer Halo Raining through the Solar Neighborhood
Martin, Nicolas; Famaey, Benoit; Viswanathan, Akshara +5 more
We report on the discovery in the Gaia DR3 astrometric and spectroscopic catalog of a new polar stream that is found as an overdensity in action space. This structure is unique as it has an extremely large apocenter distance, reaching beyond 100 kpc, and yet is detected as a coherent moving structure in the solar neighborhood with a width of ~4 kp…
γ Columbae as a recently stripped pulsating core of a massive star
Meynet, Georges; Przybilla, Norbert; Irrgang, Andreas
Stellar cores, that is, the central regions where densities and temperatures are high enough for nuclear fusion processes to take place, are usually covered by an opaque envelope. Only in very rare cases, stars may expose their cores, for example, when a tiny fraction of them evolve into Wolf-Rayet or helium hot subdwarf stars. However, for the va…
The Accretion Flow Geometry of MAXI J1820+070 through Broadband Noise Research with Insight Hard X-ray Modulation Telescope
Zhang, S.; Bu, Qing-Cui; Zhang, Liang +25 more
Here we present a detailed study of the broadband noise in the power density spectra of the black hole X-ray binary MAXI J1820+070 during the hard state of its 2018 outburst, using Hard X-ray Modulation Telescope observations. The broadband noise shows two main humps, which might separately correspond to variability from a variable disk and two Co…
Computing optical meteor flux using global meteor network data
Vida, Denis; Brown, Peter G.; Campbell-Brown, Margaret +3 more
Meteor showers and their outbursts are the dominant source of meteoroid impact risk to spacecraft on short time-scales. Meteor shower prediction models depend on historical observations to produce accurate forecasts. However, the current lack of quality and persistent world-wide monitoring at optical meteoroid sizes has left some recent major outb…
Where are the magnetar binary companions? Candidates from a comparison with binary population synthesis predictions
Lyman, J. D.; Kouveliotou, C.; Fruchter, A. S. +7 more
It is well established that magnetars are neutron stars with extreme magnetic fields and young ages, but the evolutionary pathways to their creation are still uncertain. Since most massive stars are in binaries, if magnetars are a frequent result of core-collapse supernovae, some fractions are expected to have a bound companion at the time of obse…
Tidal star-planet interaction and its observed impact on stellar activity in planet-hosting wide binary systems
Poppenhaeger, K.; Ilic, N.; Hosseini, S. Marzieh
Tidal interaction between an exoplanet and its host star is a possible pathway to transfer angular momentum between the planetary orbit and the stellar spin. In cases where the planetary orbital period is shorter than the stellar rotation period, this may lead to angular momentum being transferred into the star's rotation, possibly counteracting t…
Investigating Galactic binary cluster candidates with Gaia EDR3
Corradi, W. J. B.; Santos, J. F. C.; Maia, F. F. S. +1 more
A number of stellar open cluster (OC) pairs in the Milky Way occupy similar positions in the phase space (coordinates, parallax, and proper motions) and therefore may constitute physically interacting systems. The characterization of such objects based on observational data is a fundamental step towards a proper understanding of their physical sta…
Low gas-phase metallicities of ultraluminous infrared galaxies are a result of dust obscuration
Chartab, Nima; Fadda, Dario; Herrera-Camus, Rodrigo +9 more
Optical spectroscopic measurements show that gas in dusty, starbursting galaxies known as ultraluminous infrared galaxies (ULIRGs) in the local Universe has a significantly lower metal content than that of gas in star-forming galaxies with similar masses. This low metal content has resulted in the claim that ULIRGs are primarily fuelled by metal-p…
Activity cycles in RS CVn-type stars
Martínez, C. I.; Buccino, A. P.; Mauas, P. J. D.
We compile a list of 120 RS CVn-type stars from the bibliography in Southern hemisphere, to search for rotation periods and activity cycles, covering a large range of luminosities and effective temperatures for late stars. For each system of the list, we use photometric data from the All Sky Automated Survey (ASAS), and complement it with our own …
The Lingering Death of Periodic Near-Sun Comet 323P/SOHO
Mutchler, Max; Kracht, Rainer; Tholen, David J. +4 more
We observed near-Sun comet 323P/SOHO for the first time using ground and space telescopes. In late 2020 December, the object was recovered at Subaru showing no cometary features on its way to perihelion. However, in our postperihelion observations, it developed a long narrow tail mimicking a disintegrated comet. The ejecta, composed of at least mi…