Open AccessHeliospheric Lyman-α Absorption Toward Voyager 2
Author(s) -
Brian E. Wood,
Hans-Reinhard Müller
Publication year - 2020
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1620/1/012025
Subject(s) - heliosphere , physics , absorption (acoustics) , plasma , cosmic ray , astrophysics , astronomy , hubble space telescope , line of sight , solar wind , optics , stars , nuclear physics
Motivated by recent Voyager 2 (V2) measurements of surprisingly high plasma temperatures outside the heliopause, we study the heliospheric hydrogen Lyman-a absorption observed by the Hubble Space Telescope for the closest available line of sight to the V2 direction, 5 Pav, which is 9° from V2. The absorption is well reproduced by a typical global heliospheric model that predicts outer heliosheath temperatures of T«20, 000 K. Arbitrarily increasing these temperatures by a factor of two to be more consistent with the initial T=30, 000-50, 000 K values measured by V2 leads to significant overprediction of absorption. Thus, the high plasma temperatures first encountered by V2 near the heliopause cannot be present throughout the outer heliosheath.