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A survey of deuterated ammonia in the Cepheus star-forming region L1251
Di Francesco, James; Keown, Jared; Shirley, Yancy L. +4 more
Understanding the chemical processes during starless core and prestellar core evolution is an important step in understanding the initial stages of star and disc formation. This project is a study of deuterated ammonia, o-NH2D, in the L1251 star-forming region towards Cepheus. Twenty-two dense cores (20 of which are starless or prestell…
Ages of Main-sequence Turnoff Stars from the GALAH Survey
Wu, Yaqian; Chen, Yuqin; Bi, Shaolan +6 more
Main-sequence turnoff (MSTO) stars are good tracers of Galactic populations since their ages can be reliably estimated from atmospheric parameters. Based on the GALAH survey, we use the Yale rotation evolution code to determine the ages of 2926 MSTO stars with a mean age uncertainty of ~10% considering the variation of C and O abundances. The ages…
Eruption of the EUV Hot Channel from the Solar Limb and Associated Moving Type IV Radio Burst
Zhang, J.; Démoulin, P.; Gopalswamy, N. +3 more
Using the observations from the Solar Dynamics Observatory, we study an eruption of a hot-channel flux rope (FR) near the solar limb on 2015 February 9. The pre-eruptive structure is visible mainly in EUV 131 Å images, with two highly sheared loop structures. They undergo a slow rising motion and then reconnect to form an eruptive hot channel, as …
Vibrationally Excited Lines of HC3N Associated with the Molecular Disk around the G24.78+0.08 A1 Hypercompact H II Region
Nakamura, Fumitaka; Takakuwa, Shigehisa; Taniguchi, Kotomi +7 more
We have analyzed Atacama Large Millimeter/submillimeter Array Band 6 data of the hypercompact H II region G24.78+0.08 A1 (G24 HC H II) and report the detection of vibrationally excited lines of HC3N (v 7 = 2, J = 24 - 23). The spatial distribution and kinematics of a vibrationally excited line of HC3N (v 7
Recent formation and likely cometary activity of near-Earth asteroid pair 2019 PR2-2019 QR6
Gustafsson, Annika; Christensen, Eric; Micheli, Marco +13 more
Asteroid pairs are genetically related asteroids that recently separated (<few million years), but still reside on similar heliocentric orbits. A few hundred of these systems have been identified, primarily in the asteroid main belt. Here, we studied a newly discovered pair of near-Earth objects (NEOs): 2019 PR2 and 2019 QR6. Based on broad-ban…
Multiresolution angular momentum measurements of z 1.5-2 star-forming galaxies
Glazebrook, Karl; Fisher, Deanne B.; Obreschkow, Danail +5 more
We present detailed stellar specific angular momentum (j*) measurements of 10 star-forming galaxies at z ~ 1.5-2, using both high and low spatial resolution integral field spectroscopic data. We developed a code that simultaneously models the adaptive optics (AO) assisted observations from OSIRIS/SINFONI along with their natural seeing …
Dense Gas and Star Formation in Nearby Infrared-bright Galaxies: APEX Survey of HCN and HCO+ J = 2 → 1
Wang, Junzhi; Gao, Yu; Zhang, Zhi-Yu +6 more
Both Galactic and extragalactic studies of star formation suggest that stars form directly from dense molecular gas. To trace such high volume density gas, HCN and HCO+ J = 1 → 0 have been widely used for their high dipole moments, relatively high abundances, and often being the strongest lines after CO. However, HCN and HCO+…
Surveying the Giant H II Regions of the Milky Way with SOFIA. IV. Sgr D, W42, and a Reassessment of the Giant H II Region Census
Lim, Wanggi; Karnath, Nicole; De Buizer, James M. +2 more
This is the fourth paper exploring the infrared properties of giant H II regions with the FORCAST instrument on the Stratospheric Observatory For Infrared Astronomy (SOFIA). Our survey utilizes the census of 56 Milky Way giant H II regions identified by Conti & Crowther, and in this paper we present the 20 and 37 µm imaging data we obtai…
Cen X-3 as Seen by MAXI During Six Years
Torrejón, J. M.; Sanjurjo-Ferrín, G.; Rodes-Roca, J. J. +2 more
The aim of this work is to study both light curve and orbital phase spectroscopy of Cen X-3taking advantage of the MAXI/GSCobservation strategy. These studies allow delimiting the stellar wind properties and its interactions with the compact object. From the analysis of the light curve, we have estimated the orbital period of the binary system and…
Eta Carinae: An Evolving View of the Central Binary, Its Interacting Winds and Its Foreground Ejecta
Hamaguchi, Kenji; Corcoran, Michael F.; Russell, Christopher M. P. +13 more
FUV spectra of η Car, recorded across two decades with HST/STIS, document multiple changes in resonant lines caused by dissipating extinction in our line of sight. The FUV flux has increased nearly tenfold, which has led to increased ionization of the multiple shells within the Homunculus and photodestruction of H2. Comparison of observ…