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TOI-1728b: The Habitable-zone Planet Finder Confirms a Warm Super-Neptune Orbiting an M-dwarf Host
Cochran, William D.; Endl, Michael; Mahadevan, Suvrath +23 more
We confirm the planetary nature of TOI-1728b using a combination of ground-based photometry, near-infrared Doppler velocimetry and spectroscopy with the Habitable-zone Planet Finder. TOI-1728 is an old, inactive M0 star with Teff = ${3980}_{-32}^{+31}$ K, which hosts a transiting super-Neptune at an orbital period of ∼3.49 days. Joint f…
Local RR Lyrae stars: native and alien
Chen, X.; Zinn, R.; Layden, A. C. +1 more
Measurements of [Fe/H] and radial velocity are presented for 89 RR Lyrae (RRL) candidates within 6 kpc of the Sun. After the removal of two suspected non-RRLs, these stars were added to an existing data base, which yielded 464 RRLs with [Fe/H] on a homogeneous scale. Using data from the Gaia satellite (Data Release 2), we calculated the positions …
Mono-enriched stars and Galactic chemical evolution. Possible biases in observations and theory
Strassmeier, K. G.; Ilyin, I.; Hansen, C. J. +9 more
A long sought after goal using chemical abundance patterns derived from metal-poor stars is to understand the chemical evolution of the Galaxy and to pin down the nature of the first stars (Pop III). Metal-poor, old, unevolved stars are excellent tracers as they preserve the abundance pattern of the gas from which they were born, and hence they ar…
HD 62542: Probing the Bare, Dense Core of a Translucent Interstellar Cloud
York, Donald G.; Welty, Daniel E.; Snow, Theodore P. +1 more
We discuss the interstellar absorption from many atomic and molecular species seen in high-resolution Hubble Space Telescope/STIS UV and high signal-to-noise ratio optical spectra of the moderately reddened B3-5 V star HD 62542. This remarkable sight line exhibits both very steep far-UV extinction and a high fraction of hydrogen in molecular form,…
A search for the lenses in the Herschel Bright Sources (HerBS) sample
Eales, Stephen; Bakx, Tom J. L. C.; Amvrosiadis, Aristeidis
Verifying that sub-mm galaxies are gravitationally lensed requires time-expensive observations with oversubscribed high-resolution observatories. Here, we aim to strengthen the evidence of gravitational lensing within the Herschel Bright Sources (HerBS) by cross-comparing their positions to optical (SDSS) and near-infrared (VIKING) surveys, in ord…
Kinematics of RR Lyrae stars in the Galactic bulge with OGLE-IV and Gaia DR2
Mao, Shude; Pietrukowicz, Pawel; Shen, Juntai +2 more
We analyse the kinematics and spatial distribution of 15 599 fundamental-mode RR Lyrae (RRL) stars in the Milky Way bulge by combining OGLE-IV photometric data and Gaia DR2 proper motions. We show that the longitudinal proper motions and the line-of-sight velocities can give similar results for the rotation in the Galactic central regions. The ang…
Is Extended Hard X-Ray Emission Ubiquitous in Compton-thick AGN?
Elvis, Martin; Risaliti, Guido; Fabbiano, G. +4 more
The recent Chandra discovery of extended ∼kiloparsec-scale hard (>3 keV) X-ray emission in nearby Compton-thick (CT) active galactic nuclei (AGN) opens a new window to improving AGN torus modeling and investigating how the central supermassive black hole interacts with and impacts the host galaxy. Since there are only a handful of detections so…
Inverse First Ionization Potential Effects in Giant Solar Flares Found from Earth X-Ray Albedo with Suzaku/XIS
Maeda, Yoshitomo; Katsuda, Satoru; Sato, Kosuke +21 more
We report X-ray spectroscopic results for four giant solar flares that occurred on 2005 September 7 (X17.0), 2005 September 8 (X5.4), 2005 September 9 (X6.2), and 2006 December 5 (X9.0), obtained from Earth albedo data with the X-ray Imaging Spectrometer (XIS) on board Suzaku. The good energy resolution of the XIS (FWHM ∼ 100 eV) enables us to sep…
Three discoveries of γ Cas analogues from dedicated XMM-Newton observations of Be stars
Smith, Myron A.; Nazé, Yaël; Torrejón, José M. +5 more
In the last years, a peculiarity of some Be stars - their association with unusually hard and intense X-ray emission - was shown to extend beyond a mere few cases. In this paper, we continue our search for new cases by performing a limited survey of 18 Be stars using XMM-Newton. The targets were selected either on the basis of a previous X-ray det…
Kalkayotl: A cluster distance inference code
Miret-Roig, N.; Bouy, H.; Casamiquela, L. +5 more
Context. The high-precision parallax data of the Gaia mission allows for significant improvements in the distance determination to stellar clusters and their stars. In order to obtain accurate and precise distance determinations, systematics such as parallax spatial correlations need to be accounted for, especially with regard to stars in small sk…