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The Core Mass Function in the Orion Nebula Cluster Region: What Determines the Final Stellar Masses?
Sanhueza, Patricio; Mairs, Steve; Nakamura, Fumitaka +29 more
Applying dendrogram analysis to the CARMA-NRO C18O (J = 1-0) data having an angular resolution of ∼8″, we identified 692 dense cores in the Orion Nebula Cluster region. Using this core sample, we compare the core and initial stellar mass functions in the same area to quantify the step from cores to stars. About 22% of the identified cor…
Precise Ages of Field Stars from White Dwarf Companions in Gaia DR2
Qiu, Dan; Tian, Hai-Jun; Liu, Gao-Chao +5 more
We analyze 4050 wide binary star systems involving a white dwarf (WD) and usually a main-sequence (MS) star, drawn from the large sample assembled by Tian et al. Using the modeling code BASE-9, we determine the system's ages, the WD progenitors' zero-age MS masses, the extinction values (AV), and the distance moduli. Discarding the case…
Idunn Mons: Evidence for Ongoing Volcano-tectonic Activity and Atmospheric Implications on Venus
D'Incecco, P.; Filiberto, J.; López, I. +2 more
In 2010 the ESA Venus Express Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument first observed 1 µm emissivity anomalies over the top and eastern flank of Idunn Mons (46° S; 146° W), a 200 km wide volcano located in Imdr Regio, a volcano-dominated large volcanic rise of Venus. The anomalies suggest the presence of chemica…
Spatially Resolved RGS Analysis of Kepler's Supernova Remnant
Katsuda, Satoru; Sato, Toshiki; Hughes, John P. +4 more
The distribution and kinematics of the circumstellar medium (CSM) around a supernova remnant (SNR) tell us useful information about the explosion of its natal supernova (SN). Kepler's SNR, the remnant of SN 1604, is widely regarded to be of Type Ia origin. Its shock is moving through a dense, asymmetric CSM. The presence of this dense gas suggests…
The tidal stream generated by the globular cluster NGC 3201
Miralda-Escudé, Jordi; Palau, Carles G.
We detect a tidal stream generated by the globular cluster NGC 3201 extending over ~140 deg on the sky, using the Gaia DR2 data, with the maximum-likelihood method we presented previously to study the M68 tidal stream. Most of the detected stream is the trailing one, which stretches in the southern Galactic hemisphere and passes within a close dis…
TESS Observations of Be Stars: General Characteristics and the Impulsive Magnetic Rotator Model
Balona, Luis A.; Ozuyar, Dogus
Evidence of rotational light modulation in 30%-40% of normal B stars is presented, suggesting the presence of starspots and photospheric activity. On this basis, we propose that mass loss in Be stars is a result of magnetic reconnection coupled with rapid but not necessarily near-critical rotation. The ejected matter is trapped at two diametricall…
Analytical Framework for Space Debris Collision Avoidance Maneuver Design
Di Lizia, Pierluigi; Colombo, Camilla; Gonzalo, Juan Luis
An analytical formulation for collision avoidance maneuvers involving a spacecraft and a space debris is presented, including solutions for the maximum deviation and minimum collision probability cases. Gauss' planetary equations and relative motion equations are used to map maneuvers at a given time to displacements at the predicted close approac…
ALMA and IRIS Observations of the Solar Chromosphere. II. Structure and Dynamics of Chromospheric Plages
Martínez-Sykora, Juan; De Pontieu, Bart; Chintzoglou, Georgios +7 more
We propose and employ a novel empirical method for determining chromospheric plage regions, which seems to better isolate a plage from its surrounding regions than other methods commonly used. We caution that isolating a plage from its immediate surroundings must be done with care in order to successfully mitigate statistical biases that, for inst…
Lessons learned from SPHERE for the astrometric strategy of the next generation of exoplanet imaging instruments
Henning, Thomas; Boccaletti, Anthony; Wahhaj, Zahed +14 more
Measuring the orbits of directly imaged exoplanets requires precise astrometry at the milliarcsec level over long periods of time due to their wide separation to the stars (≳10 au) and long orbital period (≳20 yr). To reach this challenging goal, a specific strategy was implemented for the instrument Spectro-Polarimetric High-contrast Exoplanet Re…
Radio pulsations from the γ-ray millisecond pulsar PSR J2039-5617
Belfiore, A.; Venter, C.; Possenti, A. +9 more
The predicted nature of the candidate redback pulsar 3FGL J2039.6-5618 was recently confirmed by the discovery of γ-ray millisecond pulsations (Clark et al., hereafter Paper I), which identify this γ-ray source as PSR J2039-5617. We observed this object with the Parkes radio telescope in 2016 and 2019. We detect radio pulsations at 1.4 and 3.1 GHz…