{"schema":"pubphys.bundle/1","record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"a259dde1d195403fdf804a9cfd4b6125758e4864576b502b6cf8695658bd1847","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b","f23bf6d66ef21b310a438bb0f3be7060da5408602e867becf89834c08caa3fc7"],"salt":"15145b05a8fe085fe2236169dac02e7204f752d823501ee70eb4f92c0fc3e443","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"astro.sn-ia-progenitors.missing-companions","kind":"phenomenon","literature_status":"open","n":"2","parents":[],"plain":"If a white dwarf explodes while pulling gas from a normal star, that companion should survive and be seen near the center of the debris. Deep searches of young remnants have found no such star.","posed_since":"","precise":"Single-degenerate models predict a surviving donor at the center of young SN Ia remnants (for example Tycho, Kepler, SN 1006, SNR 0509-67.5), inflated and overluminous for $10^{3} \\text{ to } 10^{4}\\,\\mathrm{yr}$ and moving at a few hundred km/s; deep HST searches exclude such stars in several remnants. Explain the nondetections (double-degenerate origin, spin-up/spin-down delay that lets the donor shrink, or misidentified models), and reconcile the observed hypervelocity white dwarfs moving above $1000\\,\\mathrm{km/s}$ with the number expected if double detonations eject surviving companions.","problem_ref":"f23bf6d66ef21b310a438bb0f3be7060da5408602e867becf89834c08caa3fc7","references":"","settled_by":"A complete census of hypervelocity runaway white dwarfs from Gaia compared with the predicted ejection rate, together with deep companion limits in a larger set of Ia remnants.","status_note":"Hypervelocity runaway white dwarfs found in Gaia data since 2018 are candidate survivors of double detonations; whether their numbers match the SN Ia rate is debated.","title":"Why are surviving companion stars absent near Type Ia remnants?","topic_ref":null},"content_withheld":"false","files":[],"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"231daafcf9a99167fa5895cba0d754af253fc169cc2dd11ebf4c52b7976316b9","schema":"pubphys.attested/1"},"id_token":null,"id_token_withheld":"false","envelope":{"attested_hash":"bdac8915e3fdb55b7f14f8973517d720ca8542b151e5d271ca01d5708edfd27f","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"qmIgMcSF78AgJyXHzCQE9dJRCiJFz5YLGBIAHs5hF2MBHjnhg5tafV98DOS4kUNMJ88jwBjTrHNkxYHbcVzABg"},"schema":"pubphys.envelope/1"},"ots":{"attested":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEIvayJFeP9tVt_FPiXNRfXIMqFQrFR5dJxygHVcI7f0n_xIL2OXTKqEGeLHy1W7ZAcZ5uNcPJhKsS6xiX5Iz0vTUojCPAgIvhmmx5b0i4SjHuSd_iPCmqZCMjhPxa5geQM3j_FWggI8CC1kB0IlNWjdeYZmly-IQ7XTyVv1_KrVd7KMdkLREiohQjxIEj2CDvQ_nxXC45xT-vyoe_N3b6faQ2dArRq-kThHH3KCPAgggKVGAD2eOENQsTOaSjAefhwrqVVOW-HvOKAFIErzWII8SBjYdPXoEgk23uEQY-4dJwglsTn1Sd0gFcSBZ98oXXnOQjwIIg82Jvk6sG9d_qFEsDPR33QWZO6pmDRJWIBF6p7sCc5CPEgraRI2npokG3tsYuZYconfMt0ARYLxAQQuCOiQUqeUM8I8SDArwsGYVuomKH_DJiJGziPwECn7skqn20TGM58Ezco0wjwIIgwugvlgSNOmTWMhquqetKjeLf0x7d1a1MH4KU52JbFCPAg3mczMYDKOd7Nhf3ojA9ZvuTsN66Y1NnyYTp9j8GKQNwI8SCvAiiN-Hrv7IEejd8wdUihoozu5KOvpoBFJ0vg3UnGAQj_8Ajn9YmozHwo9QjwEJ46aM9ZDv3TdtqV3ZbRsNgI8SBOF8pILGf1kodr5MKmQs6Cd93joraGn3g6UPt_-kewPwjwIOG-gmM7bd_eR4AiDMNfluS3xvr7vicLR-sCBr5qtG2cCPAgrVNFrCoeQcCxhlmnE0BzHgR8HQpZAlfqzDDFzfWb8GUI8QRq0WWT8AjZJ2cF_c7k8ACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AI9ZMS1zxd7IEI8BDd00WgJZ0RncsC1Fyai_4aCPEgvxMFrnu7F05IW5INiraQ3OVEYMjNx6JfBxw1Q4jPLi4I8QRq0WWS8Ag2zxPAtI5JsP8Ag9_jDS75DI4uLWh0dHBzOi8vYWxpY2UuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZwjxIHAnv4KFFf4uiYEFJvLxiMxSyz8VowJP4roTfDD9h7bICPAgj5tgvbNF7mxSP4jGGE66ezUFRLnI4g1VTkvuV4VtCPAI8CCxlc1HuKORuHgn7DYIYcDhc4oo99OkTWBEvddBypoa7AjwIFcjjaF8kDNDYCZGaNISlRjvX-I7in-QNwsr4JYQbFJvCPAgnl0k4gs7LuY5i1umiHO-J7My3uBThLJUWQoY9LdVSrQI8SA6-Ft11_K_GqMNWYhkVsVqCFvXSYbp4S8JoLsLBnUzvgjxIBC8_mAE7JBP35SNxDBcG7joLJwURpMxdV2vSO64_jEOCPEge04Coj1xSi7CE8UwqiBGNhPyZ5QdD_YZwn-heSdObU4I8SBgdDSgr3VUx1j8m_pK7-OzMwwFgXeLy43ujffCv-hf5AjwIMl-PnAt4xjoBEVU4-nkyN0NKRa9AvX4kEMfllFyIJS9CPFZAQAAAAHz4rV-uwQFg02bVnEMUFgpIdGKjM4tWuID1kTVnrjisAAAAAAA_v___wJURAIAAAAAABYAFBFys2oc0-U-bYrC3VulGLzND5fbAAAAAAAAAAAiaiDwBHLTDgAICPEgMJIBYi46xOIuFDwzJ9nOx14ngW5HbglUf65ORpkoIYcICPAgHgGWEGCDHWgscwT92NOoJ7s-ezbPkyiWr2RnYZDC_dwICPAgtffMyyLu-MscJsDc0dzwGspwSrrmvVAnMNgsgWhHClgICPAgMUl1OfBDUwhp5VZjHwVA0nuz1F5HZTUJCHAnM1L1F3MICPAgStK7UWpnrUueV5EaE7uE0y6BLMp6EANmrbhrTqEBZu8ICPAg5LVW7IHtUL5mNOvPx1hOTfLMmqlQ7t9EFW-KDtrISIQICPAgABgXZ6upFU8qiDQKFtQFpqkjKwl0PsxM4JUjVLlDKbkICPAgEwb96FiOhjlbwI8GFZQ4a5GXwxs4bUdqVOMKrtBWV30ICPEgqBg-wp0c8CAPV9k6J7wIa9_GtQfpWmhpE1zqFZyi2pQICPAg2pZLTVPGJbriiz0UhMytYDVYAXOgQnWDcrMOewK9O8cICPEgxm3QwzbvT4siJzubQGnST67bWv-exYwSPP1KDi7CaUwICPEgm6udUudfjUaM0gUFTylKGDMypj7ptMTG0zmxd_T5yTcICPAgMpOInkjFCVp1pOZhfZnyPAl8hdWGmHzQcrGLgLwSKLgICAAFiJYNc9cZAQPzpjs"],"envelope":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEINi5DsAKiE5db1CM4Q2Jrajtvpynr3r04AxLFPJ1bp5vxIDYpLwAlYmzlAK_lPYevaFEqSmBjvxh9ubuHjA_dYqUhCPAg9hsGQx4iu0iFYmefYgPy_8Rvn2g5bs6_PV0HEdN1nvkI8SBSyWwgIiLKXMPV8LK6qmIdTSl_qtiaNy4lLn8BlnvaggjxIJ6iaRJ-0aNQ6Djl38cAaX4gBIAEvPq0oeKEYRXiSVnDCPEgUYntipbXZaB8Z9NA63PGabazIUsv7hAQdDVRQm1tu3AI8CAVAPLzaAcrhgg2xOqPcopUwpG6cBOw5ziAAivw1NkF9wjxIEQEcfof0fTRSONQtK0JcKN996uK3Kq9FGO8vxPBfScPCPEgET84erh4QMqfDxFWGLBJaZS5EYFN7oYAm7iWbswJgxQI8CDsCcIzBovmyR1v7IXhYg1Z7m0X4dWZvLS_NU94HSk3sQjxIJdQdDsL3v2lA7qZb8kMJtOgaTQmbgchdPcS5lYJqDLnCPAgkPXX-naXR0fRIdS-sEDlzYmtMvSCNH42ESUF0QXb6NUI8CDQo_sIWZiWXaTGRSQBLmU-lHJKskYKqsjO1r02DhB8LAj_8Ajn9YmozHwo9QjwEJ46aM9ZDv3TdtqV3ZbRsNgI8SBOF8pILGf1kodr5MKmQs6Cd93joraGn3g6UPt_-kewPwjwIOG-gmM7bd_eR4AiDMNfluS3xvr7vicLR-sCBr5qtG2cCPAgrVNFrCoeQcCxhlmnE0BzHgR8HQpZAlfqzDDFzfWb8GUI8QRq0WWT8AjZJ2cF_c7k8ACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AI9ZMS1zxd7IEI8BDd00WgJZ0RncsC1Fyai_4aCPEgvxMFrnu7F05IW5INiraQ3OVEYMjNx6JfBxw1Q4jPLi4I8QRq0WWS8Ag2zxPAtI5JsP8Ag9_jDS75DI4uLWh0dHBzOi8vYWxpY2UuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZwjxIHAnv4KFFf4uiYEFJvLxiMxSyz8VowJP4roTfDD9h7bICPAgj5tgvbNF7mxSP4jGGE66ezUFRLnI4g1VTkvuV4VtCPAI8CCxlc1HuKORuHgn7DYIYcDhc4oo99OkTWBEvddBypoa7AjwIFcjjaF8kDNDYCZGaNISlRjvX-I7in-QNwsr4JYQbFJvCPAgnl0k4gs7LuY5i1umiHO-J7My3uBThLJUWQoY9LdVSrQI8SA6-Ft11_K_GqMNWYhkVsVqCFvXSYbp4S8JoLsLBnUzvgjxIBC8_mAE7JBP35SNxDBcG7joLJwURpMxdV2vSO64_jEOCPEge04Coj1xSi7CE8UwqiBGNhPyZ5QdD_YZwn-heSdObU4I8SBgdDSgr3VUx1j8m_pK7-OzMwwFgXeLy43ujffCv-hf5AjwIMl-PnAt4xjoBEVU4-nkyN0NKRa9AvX4kEMfllFyIJS9CPFZAQAAAAHz4rV-uwQFg02bVnEMUFgpIdGKjM4tWuID1kTVnrjisAAAAAAA_v___wJURAIAAAAAABYAFBFys2oc0-U-bYrC3VulGLzND5fbAAAAAAAAAAAiaiDwBHLTDgAICPEgMJIBYi46xOIuFDwzJ9nOx14ngW5HbglUf65ORpkoIYcICPAgHgGWEGCDHWgscwT92NOoJ7s-ezbPkyiWr2RnYZDC_dwICPAgtffMyyLu-MscJsDc0dzwGspwSrrmvVAnMNgsgWhHClgICPAgMUl1OfBDUwhp5VZjHwVA0nuz1F5HZTUJCHAnM1L1F3MICPAgStK7UWpnrUueV5EaE7uE0y6BLMp6EANmrbhrTqEBZu8ICPAg5LVW7IHtUL5mNOvPx1hOTfLMmqlQ7t9EFW-KDtrISIQICPAgABgXZ6upFU8qiDQKFtQFpqkjKwl0PsxM4JUjVLlDKbkICPAgEwb96FiOhjlbwI8GFZQ4a5GXwxs4bUdqVOMKrtBWV30ICPEgqBg-wp0c8CAPV9k6J7wIa9_GtQfpWmhpE1zqFZyi2pQICPAg2pZLTVPGJbriiz0UhMytYDVYAXOgQnWDcrMOewK9O8cICPEgxm3QwzbvT4siJzubQGnST67bWv-exYwSPP1KDi7CaUwICPEgm6udUudfjUaM0gUFTylKGDMypj7ptMTG0zmxd_T5yTcICPAgMpOInkjFCVp1pOZhfZnyPAl8hdWGmHzQcrGLgLwSKLgICAAFiJYNc9cZAQPzpjs"]},"log":{"leaf_index":"2422","tree_size":"3804","proof":["3e40dd6ff8ce728cbab789b47ceb42a7e1b5a8b1965539a4756aa28eaf863399","5b6e48f66a2fd113b7d674663982d4eb149d904c06228dc143164274fbfda8c0","3dffd679315f205464e05ec02c392519f4d379cc080ec1712ee3b7899d1c6c3e","89255e8ac006b8fbd7c6b29c273960fb3a1d2f710228e5b7b1aa93617fceede6","2cbdfae0dd924dfaf18326af1cdb3112a7af43bb54dc29fd564f6a4954b3fd56","a989b4fa0838d2c30a0dfbafd589348b3784e77b27d025cc0e5ec92b29770c6d","54797267dc988bb974a7f9973996aa397c85209d28a911ca164e871ee58b0c37","0e333b0bb1d5b3a0837c7007c90874beee2fb89206b164572bfa2f0648b1cb1e","ad2bf8922b230304eb5887f66a1631d0d013048aef3d1e5c2bce55da65e76cef","453fe2db8b5276d732edac85634e8be036b4709a91a2584f32a4b9edcc8ca9de","325287f5a43e4f3ad4072ec4bd53d43c50c1393021a056122e9cb0fad83b868f","3c578dccc15502c5f3efe228cadc99fee76ab536ed01f66b14d316fdcc157429"],"checkpoint":"pubphys.com/log/v1\n3804\nAK6t4qgu96+M9wScTrIlsJ10d/zhKVEtYguyM3aeJvo=\n\n— pubphys.com/log/v1 JFPwIPP8EtoxgcsQg7V7CwIdL4UKPqJtpv+eB8sFNJjyQHIdyA1VabmBsPyLqq2bLxJPn57rA6fQi8y0QDDjRXHvlQg=\n","promise":"pubphys.com/log/v1 promise\n00dbbd009f5c9abbd9e0b2635a43947b3c4cef5d626656a01226670842493f52\n2422\n2026-10-15T23:43:57Z\n2026-10-16T01:43:57Z\n\n— pubphys.com/log/v1 JFPwIERUSANc15cVJyPL8OQfWz42Jivt/sMCiFddVXClykYXM3YBpFLJ45XtpjoCUdpGp6s6xZGwJx5WaP3Tds9NmA0=\n"},"orcid_key_evidence":[],"attesting":null}