Pith Number

pith:SPDQBAVJ

pith:2026:SPDQBAVJLA7TPNPRYLAWDMMDLJ

not attested not anchored not stored refs resolved

Hot DQs, magnetic and metal-polluted white dwarfs: spectroscopic insights from a Gaia machine-learning-selected 500 pc sample

Aina Ferrer i Burjachs, Alberto Rebassa Mansergas, Enrique Miguel Garc\'ia Zamora, Santiago Torres Gil

Machine-learning classifications from low-resolution Gaia spectra accurately identify white dwarf types, showing most massive DB candidates are magnetic white dwarfs or warm DQs instead of genuine helium-rich stars.

arxiv:2605.16493 v1 · 2026-05-15 · astro-ph.SR · astro-ph.GA

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\usepackage{pith}
\pithnumber{SPDQBAVJLA7TPNPRYLAWDMMDLJ}

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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.

Claims

C1strongest claim

We find machine-learning classifications are highly accurate (> 90% for spectral types in their training sets), despite the low resolution of Gaia spectra. We show 'massive DBs' to be mostly magnetic white dwarfs and warm DQs, with only 5 of 112 observed (4.46%) confirmed as genuine DBs.

C2weakest assumption

Visual inspection of the medium-resolution OSIRIS spectra provides an accurate, objective ground truth for spectral types that is free of significant subjectivity or selection bias in the 255-object sample.

C3one line summary

Spectroscopic follow-up validates high accuracy of ML classification for Gaia white dwarf spectra and reclassifies most 'massive DB' candidates as magnetic white dwarfs or warm DQs consistent with merger origins.

References

51 extracted · 51 resolved · 0 Pith anchors

[1] Althaus, L. G., Córsico, A. H., Isern, J., & García-Berro, E. 2010, A&A Rev., 18, 471 Bédard, A. 2024, Ap&SS, 369, 43 Bédard, A., Bergeron, P., & Brassard, P. 2022a, ApJ, 930, 8 Bédard, A., Brassard, 2010

[2] 2019, ApJ, 876, 67 2019

[3] 2011, ApJ, 737, 28 2011

[4] 2023, MNRAS, 523, 3363 2023

[5] Blouin, S., Dufour, P., Thibeault, C., & Allard, N. F. 2019, ApJ, 878, 63 2019

Formal links

2 machine-checked theorem links

Receipt and verification

First computed	2026-05-20T00:02:25.280208Z
Builder	pith-number-builder-2026-05-17-v1
Signature	Pith Ed25519 (`pith-v1-2026-05`) · public key
Schema	pith-number/v1.0

Canonical hash

93c70082a9583f37b5f1c2c161b1835a771a1f31e4fc382775952017d8dc8dd2

Aliases

arxiv: 2605.16493 · arxiv_version: 2605.16493v1 · doi: 10.48550/arxiv.2605.16493 · pith_short_12: SPDQBAVJLA7T · pith_short_16: SPDQBAVJLA7TPNPR · pith_short_8: SPDQBAVJ

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/SPDQBAVJLA7TPNPRYLAWDMMDLJ \
  | 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: 93c70082a9583f37b5f1c2c161b1835a771a1f31e4fc382775952017d8dc8dd2

Canonical record JSON

{
  "metadata": {
    "abstract_canon_sha256": "72709377529aeec1be6612ca7e46c0a5ff57f898363649e01a9f740f7bad7844",
    "cross_cats_sorted": [
      "astro-ph.GA"
    ],
    "license": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
    "primary_cat": "astro-ph.SR",
    "submitted_at": "2026-05-15T18:00:03Z",
    "title_canon_sha256": "972ddb1923a92a82da90352f965842d83ce77d454d7c5b7ee1fcead279aedd5d"
  },
  "schema_version": "1.0",
  "source": {
    "id": "2605.16493",
    "kind": "arxiv",
    "version": 1
  }
}