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NGTS clusters survey - IV. Search for Dipper stars in the Orion Nebular Cluster
Ramsay, Gavin; Wheatley, Peter J.; Henderson, Beth A. +13 more
The dipper is a novel class of young stellar object associated with large drops in flux on the order of 10-50 per cent lasting for hours to days. Too significant to arise from intrinsic stellar variability, these flux drops are currently attributed to disc warps, accretion streams, and/or transiting circumstellar dust. Dippers have been previously…
Transit timing variation analysis of the low-mass brown dwarf KELT-1 b
Southworth, J.; Mancini, L.; Evans, D. F. +8 more
We investigate whether there is a variation in the orbital period of the short-period brown dwarf-mass KELT-1 b, which is one of the best candidates to observe orbital decay. We obtain 19 high-precision transit light curves of the target using six different telescopes. We add all precise and complete transit light curves from open databases and th…
On structural properties of Comet 67/P dust particles collected in situ by ROSETTA/COSIMA from observations of electrical fragmentation
Klaus, Hornung; Eva, Maria Mellado; Oliver, J. Stenzel +20 more
After landing on the target, the kinetic energy can be dissipated within the fragment if it consists of many elements (as in the example of the Kerttu-Ender fragment, Fig. 2). If it consists of only a few elements, as is the case for most fragments traveling longer distances, the kinetic energy is dissipated by rolling. In the case of impact fragm…
3D structure of H II regions in the star-forming complex S254-S258
Moiseev, Alexei V.; Kirsanova, Maria S.; Boley, Paul A.
The S254-258 star-forming complex is a place of massive star formation where five OB-stars have created H II regions, visible as optical nebulae, and disrupted the parental molecular gas. In this work, we study the 3D structure of these H II regions using optical spectroscopy and tunable-filter photometry with the 6- and 1-m telescopes of the Spec…
Blanco DECam Bulge Survey (BDBS). VI. Extinction Maps Toward Southern Galactic Bulge Globular Clusters
Clarkson, William I.; Rich, R. Michael; Kunder, Andrea +9 more
We present wide-field, high resolution maps of the color excess for 14 globular clusters toward the Southern Galactic bulge. The maps were derived using Gaia EDR3 astrometry and stellar photometry from the Blanco DECam Bulge Survey, which is a deep, wide-field ugrizY photometric survey of the southern Galactic bulge. Comparisons with WISE 12 &micr…
Walkaway Star Candidates in IC 348 and Their Possible Birthplaces
Fang, Min; Herczeg, Gregory J.; Ren, Bin B. +2 more
Observations and theories reveal that star-forming regions eject their members during the early evolution of the cluster. We present an initial search for stars ejected from the young cluster IC 348 based on an analysis of Gaia EDR3 astrometry of previously identified members. We identify six candidate walkaway stars with projected velocities of 5…
The Effelsberg survey of FU Orionis and EX Lupi objects. II. H2O maser observations
Menten, K. M.; Ábrahám, P.; Kóspál, Á. +7 more
Context. FU Orionis (FUor) and EX Lupi (EXor) type objects are two groups of peculiar and rare pre-main sequence low-mass stars that are undergoing powerful accretion outbursts during their early stellar evolution. Although water masers are widespread in star-forming regions and serve as powerful probes of mass accretion and ejection on small scal…
GlobULeS - V. UVIT/AstroSat studies of stellar populations in NGC 362: detection of blue lurkers in a globular cluster
Dattatrey, Arvind K.; Yadav, R. K. S.; Subramaniam, Annapurni +4 more
We report the discovery of four blue lurkers with low- and extremely low mass white dwarf (ELM WD) companions in the Galactic globular cluster NGC 362 using AstroSat's Ultra Violet Imaging Telescope (UVIT). We analysed the multiwavelength spectral energy distribution (SED) of far-ultraviolet-bright main-sequence stars using data from the UVIT, Ult…
Nonthermal Motions and Atmospheric Heating of Cool Stars
Airapetian, V. S.; Ayres, T.; Testa, P. +6 more
The magnetic processes associated with the nonthermal broadening of optically thin emission lines appear to carry enough energy to heat the corona and accelerate the solar wind. We investigate whether nonthermal motions in cool stars exhibit the same behavior as on the Sun by analyzing archival stellar spectra taken by the Hubble Space Telescope, …
Two large-scale sloshing cold fronts in the outskirts of the galaxy cluster Abell 3558
Walker, S. A.; Mirakhor, M. S.; Sundquist, M. +1 more
Previous studies of the massive nearby galaxy cluster Abell 3558 reported a cold front around the cluster core, which is attributed to the sloshing of the core as it responds to the gravitational disturbance created by a past minor merger. Here, using XMM-Newton mosaic, we report the detection of two rare large-scale sloshing cold fronts far outsi…