Search Publications

Magnetic and Rotational Evolution of ρ CrB from Asteroseismology with TESS
DOI: 10.3847/1538-4357/ac1f19 Bibcode: 2021ApJ...921..122M

Kochukhov, Oleg; Drake, Jeremy J.; Stassun, Keivan G. +15 more

During the first half of main-sequence lifetimes, the evolution of rotation and magnetic activity in solar-type stars appears to be strongly coupled. Recent observations suggest that rotation rates evolve much more slowly beyond middle age, while stellar activity continues to decline. We aim to characterize this midlife transition by combining arc…

2021 The Astrophysical Journal
Gaia 18
Deciphering Solar Magnetic Activity: 140 Years of the `Extended Solar Cycle' - Mapping the Hale Cycle
DOI: 10.1007/s11207-021-01938-7 Bibcode: 2021SoPh..296..189M

Velli, Marco; McIntosh, Scott W.; Srivastava, Abhishek K. +6 more

We investigate the occurrence of the "extended solar cycle" (ESC) as it occurs in a host of observational data spanning 140 years. Investigating coronal, chromospheric, photospheric, and interior diagnostics, we develop a consistent picture of solar activity migration linked to the 22-year Hale (magnetic) cycle using superposed epoch analysis (SEA…

2021 Solar Physics
SOHO 18
Sinuous ridges in Chukhung crater, Tempe Terra, Mars: Implications for fluvial, glacial, and glaciofluvial activity
DOI: 10.1016/j.icarus.2020.114131 Bibcode: 2021Icar..35714131B

Conway, Susan J.; Balme, Matthew R.; Lewis, Stephen R. +6 more

We present a geomorphic map of Chukhung crater (38.47°N, 72.42°W) in central Tempe Terra, Mars. Chukhung crater formed ~3.6-2.1 Ga, between the early Hesperian and early Amazonian periods of Mars' geologic history. It hosts dendritic networks of crater wall valleys, broad crater floor valleys, mid- to late-Amazonian-aged debris-covered glaciers, m…

2021 Icarus
MEx 18
Benchmarking Dust Emission Models in M101
DOI: 10.3847/1538-4357/abe942 Bibcode: 2021ApJ...912..103C

Gordon, Karl D.; Leroy, Adam K.; Koch, Eric W. +7 more

We present a comparative study of four physical dust models and two single-temperature modified blackbody models by fitting them to the resolved WISE, Spitzer, and Herschel photometry of M101 (NGC 5457). Using identical data and a grid-based fitting technique, we compare the resulting dust and radiation field properties derived from the models. We…

2021 The Astrophysical Journal
Herschel 18
ASKAP observations of multiple rapid scintillators reveal a degrees-long plasma filament
DOI: 10.1093/mnras/stab139 Bibcode: 2021MNRAS.502.3294W

Kaplan, David L.; Lenc, Emil; Murphy, Tara +5 more

We present the results from an Australian Square Kilometre Array Pathfinder search for radio variables on timescales of hours. We conducted an untargeted search over a 30 deg2 field, with multiple 10-h observations separated by days to months, at a central frequency of 945 MHz. We discovered six rapid scintillators from 15-min model-sub…

2021 Monthly Notices of the Royal Astronomical Society
Gaia 18
The HST large programme on ω Centauri - IV. Catalogue of two external fields
DOI: 10.1093/mnras/stab1476 Bibcode: 2021MNRAS.505.3549S

Salaris, M.; Apai, D.; Anderson, J. +9 more

In the fourth paper of this series, we present - and publicly release - the state-of-the-art catalogue and atlases for the two remaining parallel fields observed with the Hubble Space Telescope for the large programme on ω Centauri. These two fields are located at ~12 arcmin from the centre of the globular cluster (in the west and south-west direc…

2021 Monthly Notices of the Royal Astronomical Society
eHST 18
An Improved Near-infrared Spectrum of the Archetype Y Dwarf WISEP J182831.08+265037.8
DOI: 10.3847/1538-4357/ac12cb Bibcode: 2021ApJ...920...20C

Cushing, Michael C.; Kirkpatrick, J. Davy; Gelino, Christopher R. +8 more

We present a Hubble Space Telescope/Wide-Field Camera 3 near-infrared spectrum of the archetype Y dwarf WISEP 182831.08+265037.8. The spectrum covers the 0.9-1.7 µm wavelength range at a resolving power of λ/Δλ ≈ 180 and is a significant improvement over the previously published spectrum because it covers a broader wavelength range and is un…

2021 The Astrophysical Journal
eHST 18
One Year in the Life of Young Suns: Data-constrained Corona-wind Model of κ1 Ceti
DOI: 10.3847/1538-4357/ac081e Bibcode: 2021ApJ...916...96A

Kochukhov, Oleg; Güdel, Manuel; Jin, Meng +5 more

The young magnetically active solar-like stars are efficient generators of ionizing radiation in the form of X-ray and extreme-UV (EUV) flux, stellar wind, and eruptive events. These outputs are the critical factors affecting atmospheric escape and chemistry of (exo)planets around active stars. While X-ray fluxes and surface magnetic fields can be…

2021 The Astrophysical Journal
eHST 18
Optimized modelling of Gaia-Hipparcos astrometry for the detection of the smallest cold Jupiter and confirmation of seven low-mass companions
DOI: 10.1093/mnras/stab2225 Bibcode: 2021MNRAS.507.2856F

Butler, R. Paul; Vogt, Steven S.; Oppenheimer, Rebecca +6 more

To fully constrain the orbits of low-mass circumstellar companions, we conduct combined analyses of the radial velocity data and the Gaia and Hipparcos astrometric data for eight nearby systems. Our study shows that companion-induced position and proper motion differences between Gaia and Hipparcos are significant enough to constrain orbits of low…

2021 Monthly Notices of the Royal Astronomical Society
Gaia Hipparcos 18
On the Color-Metallicity Relation of the Red Clump and the Reddening toward the Magellanic Clouds
DOI: 10.3847/1538-4357/abe530 Bibcode: 2021ApJ...910..121N

Riess, Adam G.; Yuan, Wenlong; Casagrande, Luca +2 more

The zero point of the reddening toward the Large Magellanic Cloud (LMC) has been the subject of some dispute. Its uncertainty propagates as a systematic error for methods that measure the extragalactic distance scale through knowledge of the absolute extinction of LMC stars. In an effort to resolve this issue, we used three different methods to ca…

2021 The Astrophysical Journal
Gaia eHST 18