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Eta Carinae: A Tale of Two Periastron Passages
Hamaguchi, Kenji; Corcoran, Michael F.; Russell, Christopher M. P. +15 more
Since 2002, the far-ultraviolet (FUV) flux (1150-1680 Å) of Eta Carinae, monitored by the Hubble Space Telescope/Space Telescope Imaging Spectrograph, has increased by an order of magnitude. This increase is attributed to partial dissipation of a line-of-sight (LOS) occulter that blocks the central core of the system. Across the 2020 February peri…
Hyper Suprime-Cam Legacy Archive
Takita, Satoshi; Ikeda, Hiroyuki; Koike, Michitaro +5 more
We present the launch of the Hyper Suprime-Cam Legacy Archive (HSCLA), a public archive of processed, science-ready data from the Hyper Suprime-Cam (HSC). HSC is an optical wide-field imager installed at the prime focus of the Subaru Telescope and has been in operation since 2014. While ~1/3 of the total observing time of HSC has been used for the…
Sensitivity of solar wind mass flux to coronal temperature
Matteini, L.; Owen, C. J.; Baker, D. +4 more
Solar wind models predict that the mass flux carried away from the Sun in the solar wind should be extremely sensitive to the temperature in the corona, where the solar wind is accelerated. We perform a direct test of this prediction in coronal holes and active regions using a combination of in situ and remote sensing observations. For coronal hol…
Optical and NIR spectroscopy of cool CEMP stars to probe the nucleosynthesis in low-mass AGB binary system
Ojha, D. K.; Sivarani, T.; Ninan, J. P. +4 more
We present the abundance analyses of seven carbon enhanced metal-poor (CEMP) stars to understand the origin of carbon in them. We used high-resolution optical spectra to derive abundances of various elements. We also used low-resolution near-infrared (NIR) spectra to derive the abundance of O and 12C/13C from the CO molecular…
The Hercules cluster in X-rays with XMM-Newton and Chandra
Singh, Kulinder Pal; Tiwari, Juhi
We present a detailed X-ray study of the central subcluster of the nearby ( $z\, \sim$ 0.0368) Hercules cluster (Abell 2151) identified as A2151C that shows a bimodal structure. A bright clump of hot gas with X-ray emission extending to radius $r\, \sim$ 304 kpc and $L_X = 3.03_{-0.04}^{+0.02}\times 10^{43}$ erg s-1 in the 0.4-7.0 keV e…
An intermediate-velocity H I cloud falling to the galactic disk; Possible evidence for low-metallicity H I gas originating outside the galactic disk
Tachihara, Kengo; Sasaki, Manami; Fukui, Yasuo +6 more
We found that an intermediate-velocity cloud (IVC), IVC 86-36, in H I 21 cm emission shows a head-tail distribution toward the Galactic plane with marked parallel filamentary streamers, which is extended over 40° in the sky. The distance of IVC 86-36 is constrained to be less than ∼3 kpc from absorption of a background star as determined from opti…
Comparing the spatial and kinematic distribution of gas and young stars around the shell-like structure in the CMa OB1 association
Lefloch, B.; Montmerle, T.; Gregorio-Hetem, J. +4 more
Context. The relationship between young stellar clusters and their respective parental molecular clouds remains an open issue. Recent inquiries consider the similarities between substructures of clouds and clusters and whether they are a coincidence or, rather, an indication of a physical relationship. To address these issues, we studied the CMa O…
Galactic cosmic ray modulation at Mars and beyond measured with EDACs on Mars Express and Rosetta
Johnstone, A.; Lester, M.; Wimmer-Schweingruber, R. F. +5 more
Galactic cosmic rays (GCRs) are an intrinsic part of the heliospheric radiation environment and an inevitable challenge to long-term space exploration. Here we show solar-cycle-induced GCR modulation at Mars in the period 2005-2020, along with GCR radial gradients, by comparing Mars Express and Rosetta engineering parameters to sunspot number time…
The Galactic Chemical Evolution of Chlorine
Pilachowski, C. A.; Maas, Z. G.
We measured 35Cl abundances in 52 M giants with metallicities in the range -0.5 < [Fe/H] < 0.12. Abundances and atmospheric parameters were derived using infrared spectra from CSHELL on the NASA Infrared Telescope Facility and from optical echelle spectra. We measured Cl abundances by fitting a H35Cl molecular feature a…
Heavy Positive Ion Groups in Titan's Ionosphere from Cassini Plasma Spectrometer IBS Observations
Coates, Andrew J.; Lavvas, Panayotis; Waite, J. Hunter +4 more
Titan's ionosphere contains a plethora of hydrocarbons and nitrile cations and anions as measured by the Ion Neutral Mass Spectrometer and Cassini Plasma Spectrometer (CAPS) on board the Cassini spacecraft. Data from the CAPS Ion Beam Spectrometer (IBS) sensor have been examined for five close encounters of Titan during 2009. The high relative vel…