Pith Number

pith:NXEZAKDR

pith:2001:NXEZAKDRUB6VM7A6GM6TVFMT57

not attested not anchored not stored refs pending

Collisional excitation of hydrogen and the determination of the primordial helium abundance from H II regions

(2) Main Astronomical Observatory, France, G. Stasinska (1), Kyiv, Observatoire de Paris-Meudon, Ukraine), Y. I. Izotov (2) ((1) DAEC

arxiv:astro-ph/0109253 v1 · 2001-09-17 · astro-ph

Open paper page JSON Open Graph Bundle Merged state Verified badge What is a Pith Number?

Add to your LaTeX paper

\usepackage{pith}
\pithnumber{NXEZAKDRUB6VM7A6GM6TVFMT57}

Prints a linked badge after your title and injects PDF metadata. Compiles on arXiv. Learn more · Embed verified badge

Record completeness

1 Bitcoin timestamp

2 Internet Archive

3 Author claim open · sign in to claim

4 Citations open

5 Replications open

✓ Portable graph bundle live · download bundle · merged state

The bundle contains the canonical record plus signed events. A mirror can host it anywhere and recompute the same current state with the deterministic merge algorithm.

Receipt and verification

First computed	2026-07-04T16:24:07.548541Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

6dc9902871a07d567c1e333d3a9593efde0fd2ba429e9747210420f34dab85d0

Aliases

arxiv: astro-ph/0109253 · arxiv_version: astro-ph/0109253v1 · doi: 10.48550/arxiv.astro-ph/0109253 · pith_short_12: NXEZAKDRUB6V · pith_short_16: NXEZAKDRUB6VM7A6 · pith_short_8: NXEZAKDR

Agent API

Resolver JSON Graph JSON Events JSON Schema Signing key

Verify this Pith Number yourself

curl -sH 'Accept: application/ld+json' https://pith.science/pith/NXEZAKDRUB6VM7A6GM6TVFMT57 \
  | jq -c '.canonical_record' \
  | python3 -c "import sys,json,hashlib; b=json.dumps(json.loads(sys.stdin.read()), sort_keys=True, separators=(',',':'), ensure_ascii=False).encode(); print(hashlib.sha256(b).hexdigest())"
# expect: 6dc9902871a07d567c1e333d3a9593efde0fd2ba429e9747210420f34dab85d0

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "df89ddff904bb8a060c4c50b42754e54bb0a72eaa58da89fe033d6509d948d67",
    "cross_cats_sorted": [],
    "license": "",
    "primary_cat": "astro-ph",
    "submitted_at": "2001-09-17T11:02:53Z",
    "title_canon_sha256": "5666630640c5a8c0dacb0bad162ce4f442fbe6e6967af37ceb2ed730dc990e50"
  },
  "schema_version": "1.0",
  "source": {
    "id": "astro-ph/0109253",
    "kind": "arxiv",
    "version": 1
  }
}