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Semiempirical Modeling of the Atmospheres of the M Dwarf Exoplanet Hosts GJ 832 and GJ 581
France, Kevin; Linsky, Jeffrey L.; Buccino, Andrea P. +2 more
Stellar ultraviolet (UV) radiation drives photochemistry, and extreme-ultraviolet (EUV) radiation drives mass loss in exoplanet atmospheres. However, the UV flux is partly unobservable due to interstellar absorption, particularly in the EUV range (100-912 Å). It is therefore necessary to reconstruct the unobservable spectra in order to characteriz…
TOI-532b: The Habitable-zone Planet Finder confirms a Large Super Neptune in the Neptune Desert orbiting a metal-rich M-dwarf host
Kobulnicky, Henry A.; Cochran, William D.; Mahadevan, Suvrath +30 more
We confirm the planetary nature of TOI-532b, using a combination of precise near-infrared radial velocities with the Habitable-zone Planet Finder, Transiting Exoplanet Survey Satellite (TESS) light curves, ground-based photometric follow up, and high-contrast imaging. TOI-532 is a faint (J ~ 11.5) metal-rich M dwarf with Teff = 3957 ± 6…
Assessing the Projection Correction of Coronal Mass Ejection Speeds on Time of Arrival Prediction Performance Using the Effective Acceleration Model
Vourlidas, Angelos; Papaioannou, Athanasios; Anastasiadis, Anastasios +1 more
White light images of coronal mass ejections (CMEs) are projections on the plane of sky (POS). As a result, CME kinematics are subject to projection effects. The error in the true (deprojected) speed of CMEs is one of the main causes of uncertainty to Space Weather forecasts, since all estimates of the CME time of arrival (ToA) at a certain locati…
The Atacama Cosmology Telescope: A Search for Planet 9
Hasselfield, Matthew; Sifón, Cristóbal; Aiola, Simone +37 more
We use Atacama Cosmology Telescope (ACT) observations at 98 GHz (2015-2019), 150 GHz (2013-2019), and 229 GHz (2017-2019) to perform a blind shift-and-stack search for Planet 9. The search explores distances from 300 au to 2000 au and velocities up to 6.'3 per year, depending on the distance (r). For a 5 Earth-mass Planet 9 the detection limit var…
The lower dayside ionosphere of Mars from 14 years of MaRS radio science observations
Tellmann, Silvia; Pätzold, Martin; González-Galindo, Francisco +5 more
This work uses a subset of "quiet" MaRS ionospheric dayside observations (MaRSquiet, 2004-2017) and a 1-D photochemical model (IonA-2) to investigate the potential formation processes of the excess electron densities merged with the base of the main ionosphere (Mm). 42% of the investigated MaRS observations contain identified Mm, which …
A Lyα Transit Left Undetected: the Environment and Atmospheric Behavior of K2-25b
Youngblood, Allison; Mann, Andrew W.; Charbonneau, David +6 more
K2-25b is a Neptune-sized exoplanet (3.45R⊕) that orbits its M4.5 host with a period of 3.48 days. Due to its membership in the Hyades Cluster, the system has a known age (727 ± 75 Myr). K2-25b's youth and its similarities with Gl 436b suggested that K2-25b could be undergoing strong atmospheric escape. We observed two transits of K2-25…
Characteristics of Magnetic Holes in the Solar Wind Revealed by Parker Solar Probe
Zhang, J.; Huang, S. Y.; Xu, S. B. +6 more
We present a statistical analysis for the characteristics and radial evolution of linear magnetic holes (LMHs) in the solar wind from 0.166 to 0.82 au using Parker Solar Probe observations of the first two orbits. It is found that the LMHs mainly have a duration less than 25 s and the depth is in the range from 0.25 to 0.7. The durations slightly …
Gemini Planet Imager Spectroscopy of the Dusty Substellar Companion HD 206893 B
Duchêne, G.; Doyon, R.; Saumon, D. +55 more
We present new near-infrared Gemini Planet Imager (GPI) spectroscopy of HD 206893 B, a substellar companion orbiting within the debris disk of its F5V star. The J, H, K1, and K2 spectra from GPI demonstrate the extraordinarily red colors of the object, confirming it as the reddest substellar object observed to date. The significant flux increase t…
Simulations of radio-wave anisotropic scattering to interpret type III radio burst data from Solar Orbiter, Parker Solar Probe, STEREO, and Wind
Maksimovic, M.; Bale, S. D.; Bonnin, X. +9 more
Aims: We use multi-spacecraft observations of individual type III radio bursts to calculate the directivity of the radio emission. We compare these data to the results of ray-tracing simulations of the radio-wave propagation and probe the plasma properties of the inner heliosphere.
Methods: We used ray-tracing simulations of radio-wave p…
Suprathermal particles from corotating interaction regions during the first perihelion pass of Solar Orbiter
Kulkarni, S. R.; Rodríguez-Pacheco, J.; Wimmer-Schweingruber, R. F. +24 more
The first orbit of Solar Orbiter provided comprehensive measurements of six corotating interaction regions (CIRs) within 1 au. Five of these CIRs were also observed by ACE at 1 au, allowing for comparisons of the suprathermal ion intensities and spectra at different radial distances. Only subtle modulations of the 4He spectral slopes ar…