Pith Number

pith:NNUIOAIN

pith:1999:NNUIOAINZZYWJAV5QDX4NXP23X

not attested not anchored not stored refs pending

Helium abundance in the most metal-deficient blue compact galaxies: I Zw 18 and SBS 0335-052

(2) W. M. Keck Observatory, (3) Multiple Mirror Telescope Observatory, (4) National Optical Astronomy Observatories, (5) University of Virginia, C. B. Foltz (3), Charlottesville, F. H. Chaffee (2), Hawaii, Kiev, N. G. Guseva (1), R. F. Green (4), Tucson, T. X. Thuan (5) ((1) Main Astronomical Observatory, Ukraine, USA, USA), Y. I. Izotov (1)

arxiv:astro-ph/9907228 v1 · 1999-07-16 · 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{NNUIOAINZZYWJAV5QDX4NXP23X}

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	2026-05-18T02:40:27.489412Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

6b6887010dce716482bd80efc6ddfaddf3056e4439e9a2b9bc9f19b323272065

Aliases

arxiv: astro-ph/9907228 · arxiv_version: astro-ph/9907228v1 · doi: 10.48550/arxiv.astro-ph/9907228 · pith_short_12: NNUIOAINZZYW · pith_short_16: NNUIOAINZZYWJAV5 · pith_short_8: NNUIOAIN

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/NNUIOAINZZYWJAV5QDX4NXP23X \
  | 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: 6b6887010dce716482bd80efc6ddfaddf3056e4439e9a2b9bc9f19b323272065

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "6a9c86d871c97d7ad750c20112b3dcd5076ddcc7c636fb83adcc44abe8ab878b",
    "cross_cats_sorted": [],
    "license": "",
    "primary_cat": "astro-ph",
    "submitted_at": "1999-07-16T14:43:41Z",
    "title_canon_sha256": "7e936f976284571c438d978a4274025d89903e22572231b2d3bcb782a79a8b9b"
  },
  "schema_version": "1.0",
  "source": {
    "id": "astro-ph/9907228",
    "kind": "arxiv",
    "version": 1
  }
}