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Climatology of SO2 and UV absorber at Venus' cloud top from SPICAV-UV nadir dataset
DOI: 10.1016/j.icarus.2019.07.002 Bibcode: 2020Icar..33513368M

Montmessin, Franck; Bertaux, Jean-Loup; Korablev, Oleg +6 more

Following our previous work (Marcq et al., 2013, 2011), we have updated our forward radiative transfer code and processed the whole SPICAV-UV/Venus Express nadir dataset (2006-2014) in order to retrieve SO2 abundance at cloud top - assuming a SO2 decreasing scale height of 3 km and a ratio SO/SO2 tied to 10% - as w…

2020 Icarus
VenusExpress eHST 42
An ultra-massive white dwarf with a mixed hydrogen-carbon atmosphere as a likely merger remnant
DOI: 10.1038/s41550-020-1028-0 Bibcode: 2020NatAs...4..663H

Gänsicke, B. T.; Dhillon, V. S.; Tremblay, P. -E. +11 more

White dwarfs are dense, cooling stellar embers consisting mostly of carbon and oxygen1, or oxygen and neon (with a few per cent carbon) at higher initial stellar masses2. These stellar cores are enveloped by a shell of helium, which in turn, is usually surrounded by a layer of hydrogen, generally prohibiting direct observatio…

2020 Nature Astronomy
Gaia 42
Asteroseismology of luminous red giants with Kepler I: long-period variables with radial and non-radial modes
DOI: 10.1093/mnras/staa300 Bibcode: 2020MNRAS.493.1388Y

Huber, Daniel; Bedding, Timothy R.; Stello, Dennis +4 more

While long-period variables (LPVs) have been extensively investigated, especially with MACHO and OGLE data for the Magellanic Clouds, there still exist open questions in their pulsations regarding the excitation mechanisms, radial order, and angular degree assignment. Here, we perform asteroseismic analyses on LPVs observed by the 4-year Kepler mi…

2020 Monthly Notices of the Royal Astronomical Society
Gaia 42
The little things matter: relating the abundance of ultrafaint satellites to the hosts' assembly history
DOI: 10.1093/mnras/staa1199 Bibcode: 2020MNRAS.495..743B

Belokurov, Vasily; Deason, Alis J.; Bose, Sownak +1 more

Ultrafaint dwarf galaxies ( $M_\star \le 10^{5}\, {\rm M}_\odot$ ) are relics of an early phase of galaxy formation. They contain some of the oldest and most metal-poor stars in the Universe which likely formed before the epoch of hydrogen reionization. These galaxies are so faint that they can only be detected as satellites of the Milky Way. They…

2020 Monthly Notices of the Royal Astronomical Society
Gaia 42
Mapping the Galactic Disk with the LAMOST and Gaia Red Clump Sample. VI. Evidence for the Long-lived Nonsteady Warp of Nongravitational Scenarios
DOI: 10.3847/1538-4357/ab93ad Bibcode: 2020ApJ...897..119W

Wang, H. -F.; López-Corredoira, M.; Huang, Y. +6 more

By combining LAMOST DR4 and Gaia DR2 common red clump stars with age and proper motion, we analyze the amplitude evolution of the stellar warp independently of any assumption with a simple model. The greatest height of the warp disk increases with galactocentric distance in different populations and is dependent on age: the younger stellar populat…

2020 The Astrophysical Journal
Gaia 42
The Mass-Size Relation and the Constancy of GMC Surface Densities in the Milky Way
DOI: 10.3847/1538-4357/ab9bfb Bibcode: 2020ApJ...898....3L

Lada, Charles J.; Dame, T. M.

We use two existing molecular cloud catalogs derived from the same CO survey and two catalogs derived from local dust extinction surveys to investigate the nature of the giant molecular cloud (GMC) mass-size relation in the Galaxy. We find that the four surveys are well described by MGMC ∼ R2, implying a constant mean surface…

2020 The Astrophysical Journal
Gaia 42
Searching for z > 6.5 Analogs Near the Peak of Cosmic Star Formation
DOI: 10.3847/1538-4357/ab67b8 Bibcode: 2020ApJ...890...65D

Martin, Crystal L.; Chevallard, Jacopo; Shapley, Alice E. +5 more

Strong [O III]λλ4959,5007 + Hβ emission appears to be typical in star-forming galaxies at z > 6.5. As likely contributors to cosmic reionization, these galaxies and the physical conditions within them are of great interest. At z > 6.5, where Lyα is greatly attenuated by the intergalactic medium, rest-UV metal emission lines provide an altern…

2020 The Astrophysical Journal
eHST 42
The tale of the tail - disentangling the high transverse velocity stars in Gaia DR2
DOI: 10.1093/mnras/staa077 Bibcode: 2020MNRAS.492.3816A

Amarante, João A. S.; Smith, Martin C.; Boeche, Corrado

Although the stellar halo accounts for just ∼1 per cent of the total stellar mass of the Milky Way, the kinematics of halo stars encode valuable information about the origins and evolution of our Galaxy. It has been shown that the high transverse velocity stars in Gaia DR2 reveal a double sequence in the Hertzsprung-Russell (HR) diagram, indicatin…

2020 Monthly Notices of the Royal Astronomical Society
Gaia 42
ISPY-NACO Imaging Survey for Planets around Young stars. Survey description and results from the first 2.5 years of observations
DOI: 10.1051/0004-6361/201937000 Bibcode: 2020A&A...635A.162L

Queloz, D.; Quanz, S. P.; Avenhaus, H. +21 more

Context. The occurrence rate of long-period (a ≳ 50 au) giant planets around young stars is highly uncertain since it is not only governed by the protoplanetary disc structure and planet formation process, but also reflects both dynamical re-structuring processes after planet formation as well as possible capture of planets not formed in situ. Dir…

2020 Astronomy and Astrophysics
AKARI Gaia 42
Rapid late-time X-ray brightening of the tidal disruption event OGLE16aaa
DOI: 10.1051/0004-6361/202038165 Bibcode: 2020A&A...639A.100K

Kajava, Jari J. E.; Miniutti, Giovanni; Giustini, Margherita +1 more

Stars that pass too close to a super-massive black hole may be disrupted by strong tidal forces. OGLE16aaa is one such tidal disruption event (TDE) which rapidly brightened and peaked in the optical/UV bands in early 2016 and subsequently decayed over the rest of the year. OGLE16aaa was detected in an XMM-Newton X-ray observation on June 9, 2016 w…

2020 Astronomy and Astrophysics
XMM-Newton 42