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Observational evidence of third dredge-up occurrence in S-type stars with initial masses around 1 M⊙
Jorissen, A.; Van Winckel, H.; Van Eck, S. +3 more
Context. S stars are late-type giants with spectra showing characteristic molecular bands of ZrO in addition to the TiO bands typical of M stars. Their overabundance pattern shows the signature of s-process nucleosynthesis. Intrinsic, technetium (Tc)-rich S stars are the first objects on the asymptotic giant branch (AGB) to undergo third dredge-up…
Surveying the Giant H II Regions of the Milky Way with SOFIA. I. W51A
Lim, Wanggi; De Buizer, James M.
We discuss the first results from our mid-infrared (MIR) imaging survey of Milky Way Giant H II (GH II) regions with our detailed analysis of W51A, which is one of the largest GH II regions in our Galaxy. We used the FORCAST instrument on the Stratospheric Observatory For Infrared Astronomy (SOFIA) to obtain 20 and 37 µm images of the centra…
PSR J1306-40: An X-Ray Luminous Redback with an Evolved Companion
Strader, Jay; Chomiuk, Laura; Shishkovsky, Laura +1 more
PSR J1306-40 is a millisecond pulsar (MSP) binary with a non-degenerate companion in an unusually long ∼1.097 day orbit. We present new optical photometry and spectroscopy of this system, and model these data to constrain fundamental properties of the binary such as the component masses and distance. The optical data imply a minimum neutron star m…
New constraints on Lorentz invariance violation with polarized gamma-ray bursts
Wei, Jun-Jie
Lorentz invariance violations (LIV) can yield vacuum birefringence, which results in an energy-dependent rotation of the polarization vector of linearly polarized emission from astrophysical sources. It is believed that if the relative rotation angle (ΔΘ) of the polarization vector of high-energy photons with respect to that of low-energy photons …
NU Ori: a hierarchical triple system with a strongly magnetic B-type star
Grellmann, R.; Wade, G. A.; Lacour, S. +13 more
NU Ori is a massive spectroscopic and visual binary in the Orion Nebula Cluster, with four components: Aa, Ab, B, and C. The B0.5 primary (Aa) is one of the most massive B-type stars reported to host a magnetic field. We report the detection of a spectroscopic contribution from the C component in high-resolution ESPaDOnS spectra, which is also det…
Lack of high-mass pre-stellar cores in the starless MDCs of NGC 6334
Zavagno, A.; Louvet, F.; Russeil, D. +6 more
Context. The formation of high-mass stars remains unknown in many aspects. There are two competing families of models to explain the formation of high-mass stars. On the one hand, quasi-static models predict the existence of high-mass pre-stellar cores sustained by a high degree of turbulence. On the other hand, competitive accretion models predic…
Physical properties and transmission spectrum of the WASP-74 planetary system from multiband photometry
Fossati, L.; Burgdorf, M.; Snodgrass, C. +32 more
We present broad-band photometry of 11 planetary transits of the hot Jupiter WASP-74 b, using three medium-class telescopes and employing the telescope-defocusing technique. Most of the transits were monitored through I filters and one was simultaneously observed in five optical (U, g', r', i', z') and three near-infrared (J, H, K) passbands, for …
Evidence of Nonluminous Matter in the Center of M62
Colpi, Monica; Possenti, Andrea; Abbate, Federico +1 more
Theoretical models suggest that intermediate-mass black holes (IMBHs) may form and reside in the centers of globular clusters. IMBHs are still elusive to observations, but the accelerations of pulsars may bring along a unique fingerprint of their presence. In this work, we focus on the pulsars in the globular cluster M62. Using the new distance of…
An ALMA Study of the FU Ori-type Object V900 Mon: Implications for the Progenitor
Dong, Ruobing; Takami, Michihiro; Ábrahám, Péter +13 more
We present ALMA observations of 12CO, 13CO, and C18O J = 2-1 lines and the 230 GHz continuum for the FU Ori-type object (FUor) V900 Mon (d ∼ 1.5 kpc), for which the accretion burst was triggered between 1953 and 2009. We identified CO emission associated with a molecular bipolar outflow extending up to an ∼104…
Spitzer Parallax of OGLE-2018-BLG-0596: A Low-mass-ratio Planet around an M Dwarf
Stassun, Keivan G.; Han, Cheongho; Udalski, Andrzej +73 more
We report the discovery of a Spitzer microlensing planet OGLE-2018-BLG-0596Lb, with preferred planet-host mass ratio q ∼ 2 × 10-4. The planetary signal, which is characterized by a short (∼1 day) “bump” on the rising side of the lensing light curve, was densely covered by ground-based surveys. We find that the signal can be explained by…