Why the Northern Hemisphere Needs a 30-40 m Telescope and the Science at Stake: Key Targets of Opportunity on Gas and Ice Giants and their satellites

TL;DR

A 30-40 m telescope in the Northern Hemisphere is crucial for observing gas giants and their satellites, especially Uranus and Neptune, to capture time-critical phenomena and complement ELT observations.

Contribution

The paper advocates for a Northern Hemisphere 30-40 m telescope to ensure continuous observation of key targets, addressing visibility gaps for gas giants and their satellites.

Findings

Uranus observable from the North until 2055

Neptune observable from the North from 2027 onwards

Time-critical phenomena require Northern Hemisphere access

Abstract

The Extremely Large Telescope (ELT) will transform our knowledge of the outer planets and their satellite systems; however the visibility of unique targets of opportunity with high scientific value will be reduced for northern objects. Uranus' declination favors observations from the Northern Hemisphere until 2055, and Neptune will be favored from the Northern Hemisphere from 2027 for the next 90 years. Jupiter and Saturn experience cycles of better observability from either hemisphere on cycles of 10 and 30 years. These planets and their satellite systems often offer unique opportunities for discovery through time-critical observations. We argue that a 30-m class size telescope in the Northern Hemisphere with complementary scientific instrumentation to that on the ELT will secure the possibility of observing high-impact unpredictable phenomena in these systems.