Paper · S7721
An Argument for a Kilometer-Scale Nucleus of C/2019 Q4
Siraj and Loeb argue that a roughly kilometer-scale Borisov nucleus better matches an assumed ordinary Oort-cloud mass budget. An eight-kilometer alternative produces substantial tension with that benchmark, without independently disproving the larger size. Their figure uses four points for three object families, including two alternative Borisov radii. Sparse Poisson bounds do not capture every observing or population uncertainty. This is a conditional argument using reported observations, not a new measurement campaign or artificial-origin finding.
Read the paper at arxiv.orgWhat we checked
A specialist actually read all three supplied arXiv:1909.07286v2 text pages, 6,012 normalized characters, and inspected all three native layouts, the figure, both footnotes and nine bibliography entries. Root reviewed the complete frozen final analytical report/evidence and independently verified the inventory; root primary-body reading is false. Submission is 12 September 2019, revision 17 September, native draft 18 September and metadata acceptance 16 September. No final journal rendition was collated. The radius estimate is attributed through a JPL release to a Meech-led team; that release was not read in this lane.
Received written text and native layouts; originals and interpretation gaps
How we check sources
Not checked yet
- The one- and eight-kilometer Borisov points are alternatives for the same object, not independent detections. The comparison includes three object families. Its slope and mass-budget consistency are model-dependent, not a validated fit to an independently replicated survey.
- Size cubed, assumed density, Oort-cloud benchmark and extrapolated population drive the argument. Single-object Poisson bounds do not incorporate all selection, orbital, classification and measurement errors. The paper’s tentative meteor classification and historical observing context remain attributed.
- The native draft date differs from revision metadata. The literal meteor word in the Borisov orbit paragraph, a damaged apostrophe and Pan-STAARS spelling are preserved rather than silently repaired or reassigned to another object.
- Partial Breakthrough Prize Foundation support is attributed to the work; no individual recipient, award number, date, amount or Starshot earmark is stated. No personal government approach, private briefing or material custody is reported.
- Original JPL and cited bodies, raw photometry and astrometry, meteor errors, population code and selection tests, v1/journal/reviewer collation, current census, correspondence and physical-original glyph assurance remain unreviewed in this lane. Further measurements are proposed, not received.
Cite this record
Amir Siraj, Abraham Loeb. An Argument for a Kilometer-Scale Nucleus of C/2019 Q4. September 12, 2019. BioParity S7721. https://bioparity.io/sources/S7721Record data (JSON)