Evolution and Geometry of the Heliotail across 14 yr of IBEX-Hi Observations (2009–2022): A Baseline for IMAP-era Heliotail Studies
6 affiliations
- 1Southwest Research Institute
- 2University of Texas at San Antonio
- 3University of Alabama in Huntsville
- 4Princeton University
- 5Los Alamos National Laboratory
- 6Center for Astrophysics | Harvard & Smithsonian
Abstract
IBEX-Hi observed four heliotail lobes above ∼2 keV: the energetic neutral atom (ENA)-suppressed port (P) and starboard (SB) near the ecliptic and the ENA-enhanced north (N) and south (S) at midlatitudes. They trace how the latitude-dependent solar wind (SW) and solar and interstellar magnetic fields shape the downwind heliosheath (HS). Prior work, using five nonoverlapping periods over 11 yr, found cyclic P–SB motion and equatorward N–S motion in phase with the solar cycle. We extend this analysis through 2022 using 14 smoothed yearly maps and add three methods: an intensity-weighted moment tensor (for lobe shapes), spatial and temporal block uncertainty estimates, and elliptical fits to lobe centers (for motion loci). At ∼4.3 keV, downwind-hemispheric intensity drops ∼2.4× from 2009 to 2016, partially recovering by 2022; all four lobes weaken and recover together, lagging the polar coronal hole area by ∼3 yr. P and SB track the reported cyclic motion; SB shows the largest range (∼52° longitude, ∼36° latitude). N and S move equatorward through 2017 (N ∼59° to ∼27°, S ∼−48° to ∼−24°), partially returning by 2022. The N–S great circle lies near an ecliptic meridian ( α ∼ 89 . ° 3), P–SB near the ecliptic ( β ∼ 23 . ° 8), and they are not orthogonal ( γ ∼78 . ° 1), qualitatively consistent with interstellar field draping around the heliopause. Fitted motion loci constrain models: the P-lobe is least elongated, the S-lobe most elongated, the SB-lobe longest, and the N-lobe least reliable owing to ribbon contribution. Results constrain the distant tailward HS and its evolution with the solar cycle, SW, and charge-exchange cooling.
Related
- The "Fork" Geometry in the DESI Main Survey DR1: Implications of Target Selection for Galaxy Evolution Studies
- The “Fork” Geometry in the DESI Main Survey DR1: Implications of Target Selection for Galaxy Evolution Studies
- Long-Baseline VLF Observations of Solar Flares from Antarctica
- Probing departures from Schwarzschild geometry with the S301 star and kilometre-baseline interferometry
- Accretion Geometry and Variability in QS Telescopii from multi-epoch Observations
BibTeX
@article{dayeh2026evolution,
title = {{Evolution and Geometry of the Heliotail across 14 yr of IBEX-Hi Observations (2009–2022): A Baseline for IMAP-era Heliotail Studies}},
author = {M. A. Dayeh and E. J. Zirnstein and D. J. McComas and N. A. Schwadron and D. B. Reisenfeld and F. Allegrini and S. A. Fuselier and H. O. Funsten and N. Karna},
journal = {The Astrophysical Journal Supplement Series},
year = {2026},
month = oct,
doi = {10.3847/1538-4365/aea6ba},
url = {https://iopscience.iop.org/article/10.3847/1538-4365/aea6ba},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Evolution and Geometry of the Heliotail across 14 yr of IBEX-Hi Observations (2009–2022): A Baseline for IMAP-era Heliotail Studies
AU - M. A. Dayeh
AU - E. J. Zirnstein
AU - D. J. McComas
AU - N. A. Schwadron
AU - D. B. Reisenfeld
AU - F. Allegrini
AU - S. A. Fuselier
AU - H. O. Funsten
AU - N. Karna
PY - 2026
DA - 2026/10/30
JO - The Astrophysical Journal Supplement Series
DO - 10.3847/1538-4365/aea6ba
UR - https://iopscience.iop.org/article/10.3847/1538-4365/aea6ba
AB - IBEX-Hi observed four heliotail lobes above ∼2 keV: the energetic neutral atom (ENA)-suppressed port (P) and starboard (SB) near the ecliptic and the ENA-enhanced north (N) and south (S) at midlatitudes. They trace how the latitude-dependent solar wind (SW) and solar and interstellar magnetic fields shape the downwind heliosheath (HS). Prior work, using five nonoverlapping periods over 11 yr, found cyclic P–SB motion and equatorward N–S motion in phase with the solar cycle. We extend this analysis through 2022 using 14 smoothed yearly maps and add three methods: an intensity-weighted moment tensor (for lobe shapes), spatial and temporal block uncertainty estimates, and elliptical fits to lobe centers (for motion loci). At ∼4.3 keV, downwind-hemispheric intensity drops ∼2.4× from 2009 to 2016, partially recovering by 2022; all four lobes weaken and recover together, lagging the polar coronal hole area by ∼3 yr. P and SB track the reported cyclic motion; SB shows the largest range (∼52° longitude, ∼36° latitude). N and S move equatorward through 2017 (N ∼59° to ∼27°, S ∼−48° to ∼−24°), partially returning by 2022. The N–S great circle lies near an ecliptic meridian ( α ∼ 89 . ° 3), P–SB near the ecliptic ( β ∼ 23 . ° 8), and they are not orthogonal ( γ ∼78 . ° 1), qualitatively consistent with interstellar field draping around the heliopause. Fitted motion loci constrain models: the P-lobe is least elongated, the S-lobe most elongated, the SB-lobe longest, and the N-lobe least reliable owing to ribbon contribution. Results constrain the distant tailward HS and its evolution with the solar cycle, SW, and charge-exchange cooling.
SN - 0067-0049
SN - 1538-4365
ER -