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K2-140b and K2-180b - Characterization of a hot Jupiter and a mini-Neptune from the K2 mission
Kuzuhara, M.; Alonso, R.; Erikson, A. +40 more
We report the independent discovery and characterization of two K2 planets: K2-180b, a mini-Neptune-sized planet in an 8.9-d orbit transiting a V = 12.6 mag, metal-poor ([Fe/H] = -0.65 ± 0.10) K2V star in K2 campaign 5; K2-140b, a transiting hot Jupiter in a 6.6-d orbit around a V = 12.6 mag G6V ([Fe/H] = + 0.10 ± 0.10) star in K2 campaign 10. Our…
High frequencies in TESS A-F main-sequence stars
Balona, L. A.; Cunha, M. S.; Holdsworth, D. L.
The driving mechanism for high-frequency oscillations in some chemically peculiar Ap stars, the rapidly oscillating Ap stars (roAp stars), is not understood. The Transiting Exoplanet Survey Satellite mission (TESS) data provide an ideal opportunity to extend the number of roAp stars that might provide further clues to address this problem. From an…
Spectroscopic study of two new super Li-rich red clump K giants
Reddy, Bacham E.; Kumar, Yerra Bharat; Singh, Raghubar
In this paper, we report the discovery of two new super Li-rich K giants: HD 24960 and TYC 1751-1713-1. Based on high-resolution (R ≈ 60 000) spectroscopy, we have derived Li abundance of A(Li) ≈ 4.0 dex for both stars. Other elemental abundances are normal of typical K giants. Low ratios of [C/N] ≤ -0.25 and 12C/13C ≤ 10 sug…
On the post-common-envelope central star of the planetary nebula NGC 2346
Jones, David; Van Winckel, Hans; Boffin, Henri M. J. +1 more
The common-envelope phase is one of the most poorly understood phases of (binary) stellar evolution, in spite of its importance in the formation of a wide range of astrophysical phenomena ranging from cataclysmic variables to cosmologically important supernova Type Ia, and even recently discovered gravitational wave producing black hole mergers. T…
Modelling Kepler eclipsing binaries: homogeneous inference of orbital and stellar properties
Agol, E.; Kiefer, F.; Ali, A. +1 more
We report on the properties of eclipsing binaries (EBs) from the Kepler mission with a newly developed photometric modelling code, which uses the light curve, spectral energy distribution of each binary, and stellar evolution models to infer stellar masses without the need for radial velocity (RV) measurements. We present solutions and posteriors …
The WAGGS project - II. The reliability of the calcium triplet as a metallicity indicator in integrated stellar light
Kamann, Sebastian; Schiavon, Ricardo P.; Foster, Caroline +12 more
Using data from the WiFeS Atlas of Galactic Globular cluster Spectra, we study the behaviour of the calcium triplet (CaT), a popular metallicity indicator in extragalactic stellar population studies. A major caveat of these studies is that the potential sensitivity to other stellar population parameters such as age, calcium abundance, and the init…
New β Cep pulsators discovered with K2 space photometry
Aerts, C.; Bowman, D. M.; Burssens, S. +3 more
We present the discovery of three new β Cep pulsators, three new pulsators with frequency groupings, and frequency patterns in a B3Ib star, all of which show pulsations with frequencies as high as about 17 d-1, with K2 space mission photometry. Based on a Fourier analysis and iterative pre-whitening, we present a classification and eval…
A treatment procedure for GMOS/IFU data cubes: application to NGC 2835
Ricci, T. V.; Ferrari, Fabricio; Steiner, J. E. +3 more
We present a set of treatment techniques for GMOS/IFU data cubes, including correction of the differential atmospheric refraction; Butterworth spatial filtering, to remove high spatial-frequency noise; instrumental fingerprint removal; Richardson-Lucy deconvolution, to improve the spatial resolution of the observations. A comparison with HST image…
Hubble Space Telescope analysis of stellar populations within the globular cluster G1 (Mayall II) in M 31
Milone, A. P.; Bedin, L. R.; Rich, R. M. +5 more
In this paper, we present a multiwavelength analysis of the complex stellar populations within the massive globular cluster Mayall II (G1), a satellite of the nearby Andromeda galaxy projected at a distance of 40 kpc. We used images collected with the Hubble Space Telescope in UV, blue and optical filters to explore the multiple stellar population…
Flipping-up the field: gravitational feedback as a mechanism for young clusters dispersal
Kounkel, Marina; Hernández, Jesús; Román-Zúñiga, Carlos +3 more
Recent analyses of Gaia data have provided direct evidence that most young stellar clusters are in a state of expansion, with velocities of the order of ∼0.5 km s-1. Traditionally, expanding young clusters have been pictured as entities that became unbound due to the lack of gravitational binding once the gas from the parental cloud tha…