The development of HISPEC for Keck and MODHIS for TMT: science cases and predicted sensitivities

HISPEC is a new, high-resolution near-infrared spectrograph being designed for the W.M. Keck II telescope. By offering single-shot, R=100,000 between 0.98 - 2.5 um, HISPEC will enable spectroscopy of transiting and non-transiting exoplanets in close orbits, direct high-contrast detection and spectroscopy of spatially separated substellar companions, and exoplanet dynamical mass and orbit measurements using precision radial velocity monitoring calibrated with a suite of state-of-the-art absolute and relative wavelength references. MODHIS is the counterpart to HISPEC for the Thirty Meter Telescope and is being developed in parallel with similar scientific goals. In this proceeding, we provide a brief overview of the current design of both instruments, and the requirements for the two spectrographs as guided by the scientific goals for each. We then outline the current science case for HISPEC and MODHIS, with focuses on the science enabled for exoplanet discovery and characterization. We also provide updated sensitivity curves for both instruments, in terms of both signal-to-noise ratio and predicted radial velocity precision.Comment: 25 pages, 9 figures. To appear in the Proceedings of SPIE: Techniques and Instrumentation for Detection of Exoplanets XI, vol. 12680 (2023

3D simulations of realistic power halos in magnetohydrostatic sunspot atmospheres: Linking theory and observation

The well-observed acoustic halo is an enhancement in time-averaged Doppler velocity and intensity power with respect to quiet-Sun values that is prominent for the weak and highly inclined field around the penumbra of sunspots and active regions. We perform 3D linear wave modeling with realistic distributed acoustic sources in a magnetohydrostatic sunspot atmosphere and compare the resultant simulation enhancements with multiheight SDO observations of the phenomenon. We find that simulated halos are in good qualitative agreement with observations. We also provide further proof that the underlying process responsible for the halo is the refraction and return of fast magnetic waves that have undergone mode conversion at the critical a = c atmospheric layer. In addition, we also find strong evidence that fast Alfvén mode conversion plays a significant role in the structure of the halo, taking energy away from photospheric and chromospheric heights in the form of field-aligned Alfvén waves. This conversion process may explain the observed "dual-ring" halo structure at higher (>8 mHz) frequencies

Pseudostalked barnacles Xenobalanus globicipitis attached to killer whales Orcinus orca in South African waters

Several records describe pseudostalked barnacles Xenobalanus globicipitis attached to killer whales Orcinus orca, yet little is known of this association in Southern African waters. Here we describe Xenobalanus prevalence on killer whales in South African waters and assemble previous records. Killer whales were photographed opportunistically between July and September 2013. Sex and age class were determined, and if Xenobalanus were present, attachment site and colony size noted. A prevalence of 50% was recorded, with barnacles most commonly observed on the dorsal fin and tail flukes. The high prevalence of Xenobalanus on killer whales in South African waters and lack thereof on killer whales at Marion Island implies that these are separate populations, and thus we suggest Xenobalanus prevalence is an additional means to distinguish between these populations.National Research Foundation (NRF) Thuthuka programme, the South African Department of Science and Technology through the NRF, the Mohamed bin Zayed Species Conservation Fund (project number: 10251290) and the International Whaling Commission’s Southern Ocean Research Partnership.http://link.springer.com/journal/125262016-12-31hb201

Firefly: The Case for a Holistic Understanding of the Global Structure and Dynamics of the Sun and the Heliosphere

This white paper is on the HMCS Firefly mission concept study. Firefly focuses on the global structure and dynamics of the Sun's interior, the generation of solar magnetic fields, the deciphering of the solar cycle, the conditions leading to the explosive activity, and the structure and dynamics of the corona as it drives the heliosphere