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Anisotropic winds in a Wolf-Rayet binary identify a potential gamma-ray burst progenitor
Callingham, J. R.; Crowther, P. A.; Tuthill, P. G. +5 more
The massive evolved Wolf-Rayet stars sometimes occur in colliding-wind binary systems in which dust plumes are formed as a result of the collision of stellar winds1. These structures are known to encode the parameters of the binary orbit and winds2-4. Here we report observations of a previously undiscovered Wolf-Rayet system,…
First stellar spectroscopy in Leo P
Lennon, D. J.; Bastian, N.; Cioni, M. -R. L. +11 more
We present the first stellar spectroscopy in the low-luminosity (MV ∼ -9.3 mag), dwarf galaxy Leo P. Its significantly low oxygen abundance (3% solar) and relative proximity (∼1.6 Mpc) make it a unique galaxy in which to investigate the properties of massive stars with near-primordial compositions akin to those in the early Universe. Fr…
Multi-epoch Direct Imaging and Time-variable Scattered Light Morphology of the HD 163296 Protoplanetary Disk
Henning, Thomas; Nakagawa, Takao; Terada, Hiroshi +58 more
We present H-band polarized scattered light imagery and JHK high-contrast spectroscopy of the protoplanetary disk around HD 163296 observed with the High-Contrast Coronographic Imager for Adaptive Optics (HiCIAO) and Subaru Coronagraphic Extreme Adaptive Optics (SCExAO)/Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) instrument…
Astrometric and photometric study of NGC 6067, NGC 2506, and IC 4651 open clusters based on wide-field ground and Gaia DR2 data
Bisht, D.; Rangwal, Geeta; Yadav, R. K. S. +2 more
We present an analysis of three southern open star clusters NGC 6067, NGC 2506, and IC 4651 using wide-field photometric and Gaia DR2 astrometric data. They are poorly studied clusters. We took advantage of the synergy between Gaia DR2 high precision astrometric measurements and ground-based wide-field photometry to isolate cluster members and fur…
X-Ray Observations of a z ∼ 6.2 Quasar/Galaxy Merger
Fan, Xiaohui; Mulchaey, John S.; Walter, Fabian +7 more
Quasars at early redshifts (z > 6) with companion galaxies offer unique insights into the growth and evolution of the first supermassive black holes. Here, we report on a 150 ks Chandra observation of PSO J308.0416-21.2339, a z = 6.23 quasar with a merging companion galaxy identified in [C II] and rest-frame UV emission. With {72.3}-8.6
X-ray properties of z > 4 blazars
Moretti, A.; Ballo, L.; Dallacasa, D. +4 more
We present the X-ray analysis of the largest flux-limited complete sample of blazar candidates at z > 4 selected from the Cosmic Lens All Sky Survey (CLASS). After obtaining a nearly complete (24/25) X-ray coverage of the sample (from Swift-XRT, XMM-Newton, and Chandra), we analysed the spectra in order to identify the bona fide blazars. We cla…
Accounting for multiplicity in calculating eta Earth
Zink, Jon K.; Hansen, Bradley M. S.
Using the updated exoplanet population parameters of our previous study, which includes the planetary radius updates from Gaia DR2 and an inferred multiplicity distribution, we provide a revised η⊕ calculation. This is achieved by sampling planets from our derived population model and determining which planets meet our criterion for hab…
Molecular tracers of radiative feedback in Orion (OMC-1). Widespread CH+ (J = 1-0), CO (10-9), HCN (6-5), and HCO+ (6-5) emission
Cernicharo, José; Bron, Emeric; Goicoechea, Javier R. +4 more
Young massive stars regulate the physical conditions, ionization, and fate of their natal molecular cloud and surroundings. It is important to find tracers that quantify the stellar feedback processes that take place on different spatial scales. We present 85 arcmin2 velocity-resolved maps of several submillimeter molecular lines, taken…
Exomoons in the Habitable Zones of M Dwarfs
Piro, Anthony L.; Barnes, Rory; Martínez-Rodríguez, Héctor +2 more
M dwarfs host most of the exoplanets in the local Milky Way. Some of these planets, ranging from sub-Earths to super-Jupiters, orbit in their stars’ habitable zones (HZs), although many likely possess surface environments that preclude habitability. Moreover, exomoons around these planets could harbor life for long timescales and thus may also be …
The stellar initial mass function of the solar neighbourhood revealed by Gaia
Sollima, A.
I use a sample of more than 120 000 stars in the solar neighbourhood, with parallaxes, magnitudes and colours estimated with unprecedented accuracy by the second data release of the Gaia mission, to derive the initial mass function of the Galactic disc. A full-forward technique is used to take into account, for the population of unresolved binarie…