Results 41 to 50 of about 15,045 (53)

The Pre-perihelion Evolution of the Activity of Comet C/2017 K2 (Pan-STARRS) during the Water Ice-line Crossover

The Astronomical Journal
Comets, relics from the early solar system, consist of dust and ice. The ice sublimates as comets approach the Sun, ejecting dust from their nuclei seen as activity.
Yuna G. Kwon, Stefano Bagnulo, Johannes Markkanen, Ludmilla Kolokolova, Jessica Agarwal, Manuela Lippi, Zuri Gray   +6 more
doaj   +1 more source

Absence of High-mass Prestellar Cores in the Orion Giant Molecular Cloud

The Astronomical Journal
A fundamental difference between “core-fed” and “clump-fed” star-formation theories lies in the existence or absence of high-mass cores at the prestellar stage. However, only a handful of such cores have been observed.
Wenyu Jiao, Ke Wang, Fengwei Xu
doaj   +1 more source

KPF Confirms a Polar Orbit for KELT-18 b

The Astronomical Journal
We present the first spectroscopic transit results from the newly commissioned Keck Planet Finder on the Keck-I telescope at W. M. Keck Observatory. We observed a transit of KELT-18 b, an inflated ultrahot Jupiter orbiting a hot star ( T _eff = 6670 K ...
Ryan A. Rubenzahl, Fei Dai, Samuel Halverson, Andrew W. Howard, Aaron Householder, Benjamin Fulton, Aida Behmard, Steven R. Gibson, Arpita Roy, Abby P. Shaum, Howard Isaacson, Max Brodheim, William Deich, Grant M. Hill, Bradford Holden, Russ R. Laher, Kyle Lanclos, Joel N. Payne, Erik A. Petigura, Christian Schwab, Chris Smith, Guðmundur Stefánsson, Josh Walawender, Sharon X. Wang, Lauren M. Weiss, Joshua N. Winn, Edward Wishnow   +26 more
doaj   +1 more source

Peering into the Heart of the Giant Molecular Cloud G148.24+00.41: A Deep Near-infrared View of the Newly Hatched Cluster FSR 655

The Astronomical Journal
We present a detailed near-infrared study of an embedded cluster located in the hub of the giant molecular cloud G148.24+00.41 of mass ∼10 ^5 M _⊙ , with the TANSPEC instrument mounted on the 3.6 m Devasthal Optical Telescope. The hub is located near the
Vineet Rawat, M. R. Samal, D. K. Ojha, Brajesh Kumar, Saurabh Sharma, J. Jose, Ram Sagar, R. K. Yadav   +7 more
doaj   +1 more source

Stellar Variability and Distance Indicators in the Near-infrared in Nearby Galaxies. I. RR Lyrae and Anomalous Cepheids in Draco Dwarf Spheroidal

The Astronomical Journal
The Draco Dwarf spheroidal (dSph) galaxy is one of the nearest and the most dark-matter-dominated satellites of the Milky Way. We obtained multiepoch near-infrared (NIR, JHK _s ) observations of the central region of Draco dSph covering a sky area of ∼21′
Anupam Bhardwaj, Marina Rejkuba, Chow-Choong Ngeow, Marcella Marconi, Vincenzo Ripepi, Abhinna Sundar Samantaray, Harinder P. Singh   +6 more
doaj   +1 more source

Challenges in Identifying Artificial Objects in the Near-Earth Object Population: Spectral Characterization of 2020 SO

The Planetary Science Journal
Since the dawn of the Space Age, hundreds of payloads have been launched into heliocentric space. As near-Earth object (NEO) surveys search deeper for small asteroids, more artificial objects in heliocentric orbits are being discovered.
Adam Battle, Vishnu Reddy, Juan A. Sanchez, Benjamin Sharkey, Tanner Campbell, Paul Chodas, Al Conrad, Daniel P. Engelhart, James Frith, Roberto Furfaro, Davide Farnocchia, Olga Kuhn, Neil Pearson, Barry Rothberg, Christian Veillet, Richard Wainscoat   +15 more
doaj   +1 more source

Measurements of Titan’s Stratospheric Winds during the 2009 Equinox with the eSMA

The Planetary Science Journal
Saturn’s moon Titan possesses stratospheric zonal winds that places it among a sparse class of planetary bodies known to have superrotation in their atmospheres.
Siobhan Light, Mark Gurwell, Alexander Thelen, Nicholas A Lombardo, Conor Nixon   +4 more
doaj   +1 more source

Far-ultraviolet to Far-infrared Spectral Energy Distribution Modeling of the Star Formation History across M31

The Astronomical Journal
Our neighboring galaxy M31 has been recently surveyed at the far- and near-ultraviolet (FUV and NUV) with the UVIT telescope on AstroSat, which provides unprecedented sensitivity to young stellar populations.
Denis A. Leahy, Jakob Hansen, Andrew M. Hopkins   +2 more
doaj   +1 more source

Mini-RF S-band Radar Characterization of a Lunar South Pole–crossing Tycho Ray: Implications for Sampling Strategies

The Planetary Science Journal
One of the youngest features on the Moon is Tycho, an 85 km diameter impact crater with a vast ray system that spans much of the lunar nearside. As such, it serves as an important stratigraphic marker for the Moon. One of Tycho’s longest rays crosses the
Edgard G. Rivera-Valentín, Caleb I. Fassett, Brett W. Denevi, Heather M. Meyer, Catherine D. Neish, Gareth A. Morgan, Joshua T. S. Cahill, Angela M. Stickle, G. Wesley Patterson   +8 more
doaj   +1 more source

Probing the Rock Mass Fraction and Transport Efficiency inside Uranus Using 40Ar Measurements

The Planetary Science Journal
The bulk of Uranus consists of a rock–ice core, but the relative proportions of rock and ice are unknown. Radioactive decay of potassium in the silicates produces ^40 Ar.
Francis Nimmo, Jonathan Lunine, Kevin Zahnle, Lars Stixrude   +3 more
doaj   +1 more source