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The Extreme CNO-enhanced Composition of the Primitive Iron-poor Dwarf Star J0815+4729
Burgasser, Adam J.; Aguado, David S.; Allende Prieto, Carlos +2 more
We present an analysis of high-resolution Keck/HIRES spectroscopic observations of J0815+4729, an extremely carbon-enhanced, iron-poor dwarf star. These high-quality data allow us to derive a metallicity of [Fe/H] = -5.49 ± 0.14 from the three strongest Fe I lines and to measure a high [Ca/Fe] = 0.75 ± 0.14. The large carbon abundance of A(C) = 7.…
The interacting nature of dwarf galaxies hosting superluminous supernovae
Schulze, Steve; Leloudas, Giorgos; Man, Allison W. S. +3 more
Context. Type I superluminous supernovae (SLSNe I) are rare, powerful explosions whose mechanism and progenitors remain elusive. Several studies have shown a preference for SLSNe I to occur in low-metallicity, actively star-forming dwarf galaxies.
Aims: We investigate whether the host galaxies of SLSNe I show increased evidence for interactio…
Near-infrared variability in dusty white dwarfs: tracing the accretion of planetary material
Xu, Siyi; von Hippel, Ted; Su, Kate Y. L. +4 more
The inwards scattering of planetesimals towards white dwarfs is expected to be a stochastic process with variability on human time-scales. The planetesimals tidally disrupt at the Roche radius, producing dusty debris detectable as excess infrared emission. When sufficiently close to the white dwarf, this debris sublimates and accretes on to the wh…
SDSS J1004+4112: the case for a galaxy cluster dominated by primordial black holes
Hawkins, M. R. S.
Aims: This paper is aimed at providing a plausible explanation for the large amplitude microlensing events observed in the cluster-lensed quasar system, SDSS J1004+4112. The microlensed quasar images appear to lie well clear of the stellar population of the cluster, raising the possibility that the cluster dark matter is composed of compact b…
Properties of giant molecular clouds in the strongly barred galaxy NGC 1300
Ohta, Kouji; Maeda, Fumiya; Fujimoto, Yusuke +1 more
Star formation activity depends on galactic-scale environments. To understand the variations in star formation activity, comparing the properties of giant molecular clouds (GMCs) among environments with different star formation efficiency (SFE) is necessary. We thus focus on a strongly barred galaxy to investigate the impact of the galactic enviro…
The nature of CR7 revealed with MUSE: a young starburst powering extended Ly α emission at z = 6.6
Richard, Johan; Nanayakkara, Themiya; Sobral, David +11 more
CR7 is among the most luminous Ly α emitters (LAEs) known at z = 6.6 and consists of at least three UV components that are surrounded by Ly α emission. Previous studies have suggested that it may host an extreme ionizing source. Here, we present deep integral field spectroscopy of CR7 with VLT/Multi Unit Spectroscopic Explorer (MUSE). We measure e…
A Habitable-zone Earth-sized Planet Rescued from False Positive Status
Vanderburg, Andrew; Bryson, Steve; Latham, David W. +9 more
We report the discovery of an Earth-sized planet in the habitable zone of a low-mass star called Kepler-1649. The planet, Kepler-1649 c, is 1.06 ${}_{-0.10}^{+0.15}$ times the size of Earth and transits its 0.1977 ± 0.0051 ${M}_{\odot }$ "mid" M-dwarf host star every 19.5 days. It receives 74% ± 3% the incident flux of Earth, giving it an equilibr…
First detection of the carbon chain molecules 13CCC and C13CC towards SgrB2(M)
Giesen, T. F.; Stutzki, J.; Simon, R. +4 more
Context. Carbon molecules and their 13C-isotopologues can be used to determine the 12C/13C abundance ratios in stellar and interstellar objects. C3 is a pure carbon chain molecule found in star-forming regions and in stellar shells of carbon-rich late-type stars. Latest laboratory data of 13C-…
Magnetic Properties of Asteroid (162173) Ryugu
Motschmann, Uwe; Fujimoto, Masaki; Richter, Ingo +22 more
Observations of the magnetization state of asteroids indicate diverse properties. Values between 1.9 × 10-6 Am2/kg (Eros) and 10-2 Am2/kg (Braille) have been reported. A more detailed understanding of asteroidal magnetic properties allows far-reaching conclusions of the magnetization mechanism as well as…
NGTS clusters survey - II. White-light flares from the youngest stars in Orion
Jackman, James A. G.; Wheatley, Peter J.; Moyano, Maximiliano +18 more
We present the detection of high-energy white-light flares from pre-main-sequence stars associated with the Orion Complex, observed as part of the Next Generation Transit Survey (NGTS). With energies up to 5.2 × 1035 erg these flares are some of the most energetic white-light flare events seen to date. We have used the NGTS observations…