Determine the location of the TSAS-producing cloud toward B1929+10

Determine whether the cloud causing the tiny-scale atomic structure observed toward pulsar B1929+10 is located outside the Local Bubble or within, or on the wall of, the Local Bubble.

Background

The paper investigates time-variable H I absorption toward the pulsar B1929+10, previously interpreted as evidence for tiny-scale atomic structure on astronomical-unit scales. The authors combine the absorption data with three-dimensional dust maps and a model of the Local Bubble to associate the absorbing structure with a distance along the line of sight.

Their analysis places the most prominent variable absorption component at approximately 215 pc, apparently beyond the Local Bubble structure identified in the adopted model. However, the dust maps lack data within 69 pc and have insufficient spatial resolution to resolve the relevant small-scale structure. Consequently, the authors regard the external location of the TSAS-producing cloud as unresolved rather than definitive.

References

Ultimately, the limitation of physical resolution and lack of data within the inner 69 pc of the Sun preclude us from definitively concluding that the cloud causing the TSAS is located outside the LB.

— Probing the Properties of Neutral Clouds in the Vicinity of the Local Bubble: Linking three-dimensional Dust with Neutral Hydrogen Absorption  (2608.26098 - Das-Ghosh et al., 26 Aug 2026) in Section 4.1, “TSAS towards B1929+10 is not associated with the Local Bubble wall”