High Spectral Resolution X-ray Observations of the Evolved Supermassive Stellar Binary System $?$ Carinae - Iron K$?$ Band Profile Revealed with XRISM

The supermassive binary system, $?$ Carinae, is experiencing enormous wind-driven mass loss at a rate unparalleled in the rest of the Galaxy. Their wind-wind collision (WWC) continuously produces shock heated, X-ray emitting plasmas. The XRISM X-ray observatory observed the system in 2023 and 2024 when the X-ray emission began to increase toward periastron passage in 2025. This manuscript reports unprecedentedly high-resolution X-ray spectra in the iron K$?$ band between 6.2 and 7.1 keV, obtained with the Resolve X-ray microcalorimeter. The hydrogen-like (Ly$?$) and helium-like (He$?$) lines reveal three velocity components. Two of them are broadened with maximum velocities of 2000-3000 km/s, likely originating from the post-shock companion wind. The other is relatively narrow, with a Gaussian broadening of only ~290 km/s in 1 sigma, which may originate from the post-shock companion wind at the WWC stagnation point or penetrating the primary wind. The iron fluorescent lines exhibit a moderate blueshift and broadening with velocities at 100-200 km/s, consistent with the primary wind's velocity field. The spectra also confirm a Compton shoulder of the He$?$ line complex for the first time. Both fluorescing and scattering spectral profiles indicate that the binary system is seen from the companion side during these observations. The flux ratio of the Compton scattering emission to the fluorescent line suggests substantial hydrogen depletion of the primary wind, expected from CNO-cycled hydrogen nuclear fusion gas.

Authors

Publication Details

Journal
Maryland Shared Open Access Repository (USMAI Consortium)
Published
2026-02-25
DOI
https://doi.org/10.13016/m2q895-9a6a
Primary Topic
Astrophysical Phenomena and Observations
Type
article
Field-Weighted Citation Impact
0.00
Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

High Spectral Resolution X-ray Observations of the Evolved Supermassive Stellar Binary System $?$ Carinae - Iron K$?$ Band Profile Revealed with XRISM

Aya Bamba, Yoshiaki Kanemaru, Mai Takeo, Daiki Ishi et al.
Maryland Shared Open Access Repository (USMAI Consortium)
Astrophysical Phenomena and Observations
article

High Spectral Resolution X-ray Observations of the Evolved Supermassive Stellar Binary System $?$ Carinae - Iron K$?$ Band Profile Revealed with XRISM

Aya Bamba, Yoshiaki Kanemaru, Mai Takeo, Daiki Ishi, Noriko Y. Yamasaki, V. Brown, Bert Vander Meulen, Shutaro Ueda, HIROFUMI NODA, Ralf Ballhausen, Misaki Mizumoto, Rozenn Boissay-Malaquin, Yuusuke Uchida, A. Tanimoto, Asca Miyamoto, XRISM Collaboration, Anna Ogorzalek, Yuichiro Ezoe, Dan McCammon, María Díaz Trigo, Emi Goto, Michael F. Corcoran, Francisco Junqueira, Elisa Costantini, Tahir Yaqoob, Tadayasu Dotani, Hisamitsu Awaki, Yutaka Fujita, Ann Hornschemeier, Takaaki Tanaka, Shinichiro Uno, Takayuki Hayashi, Richard Mushotzky, Yukiko Ishihara, Shinya Yamada, Koji Mori, Tsunefumi Mizuno, Ikuyuki Mitsuishi, Shogo Kobayashi, Takeshi Tsuru, Megumi Shidatsu, Eric D. Miller, Chris Done, Andrew Szymkowiak, Makoto Yamauchi, Masayoshi Nobukawa, Yoshitaka Ishisaki, Robert Petre, Laura Brenneman, Hiroya Yamaguchi, Randall Smith, Toshiki Sato, Kazuhiro Nakazawa, Hiroshi Nakajima, Yuto Ichinohe, Tessei Yoshida, Satoru Katsuda, Maxim Markevitch, Javier A. Garcia, Hiromi Seta, Erin Kara, Timothy Kallman, Luigi Gallo, Jacco Vink, Caroline A. Kilbourne, Tomokage Yoneyama, Yoshitomo Maeda, Teruaki Enoto, Makoto Sawada, Hiroshi Murakami, Akihiro Furuzawa, Stephane Paltani, Takayoshi Kohmura, Nagomi Uchida, Matteo Guainazzi, Hiroshi Tsunemi, Makoto Tashiro, Keisuke Tamura, Kumiko Nobukawa, Kosuke Sato, Shigeo Yamauchi, Paul Plucinsky, Aya Kubota, Megan E. Eckart, Toru Tamagawa, Takashi Okajima, Ken Ebisawa, Yasushi Fukazawa, Hideki Uchiyama, Dominique Eckert, Marc Audard, Edmund Hodges-Kluck, Katja Pottschmidt, Shin Watanabe, Aurora Simionescu, Renata Cumbee, Frederick S. Porter, Mihoko Yukita, Satoshi Yamada, Brian McNamara, Ehud Behar, Lia Corrales, Ryuichi Fujimoto, Yuichi Terashima, Yohko Tsuboi, Kumi Ishikawa, Kenji Hamaguchi, Natalie Hell, Maurice Leutenegger, Masahiro Tsujimoto, Shun Inoue, Brian J. Williams, Hiromasa Suzuki, Kotaro Fukushima, Irina Zhuravleva, Jan-Uwe Ness, Richard L. Kelley, Michael Loewenstein, Kouichi Hagino, Shoji Ogawa, Ay?egü Tümer, Manabu Ishida, Kyoko Matsushita, Satoshi Eguchi, Liyi Gu, Adam Foster, Hiroyuki Uchida, Naomi Ota, Yukikatsu Terada, Hiromitsu Takahashi, François Mernier, Hirokazu Odaka, Hironori Matsumoto, Yoshihiro Ueda, Kazutaka Yamaoka, Jelle Kaastra, Shunji Kitamoto, Koji Mukai, Katsuhiro Hayashi, Isamu Hatsukade, Jon M. Miller
article en

Abstract

The supermassive binary system, $?$ Carinae, is experiencing enormous wind-driven mass loss at a rate unparalleled in the rest of the Galaxy. Their wind-wind collision (WWC) continuously produces shock heated, X-ray emitting plasmas. The XRISM X-ray observatory observed the system in 2023 and 2024 when the X-ray emission began to increase toward periastron passage in 2025. This manuscript reports unprecedentedly high-resolution X-ray spectra in the iron K$?$ band between 6.2 and 7.1 keV, obtained with the Resolve X-ray microcalorimeter. The hydrogen-like (Ly$?$) and helium-like (He$?$) lines reveal three velocity components. Two of them are broadened with maximum velocities of 2000-3000 km/s, likely originating from the post-shock companion wind. The other is relatively narrow, with a Gaussian broadening of only ~290 km/s in 1 sigma, which may originate from the post-shock companion wind at the WWC stagnation point or penetrating the primary wind. The iron fluorescent lines exhibit a moderate blueshift and broadening with velocities at 100-200 km/s, consistent with the primary wind's velocity field. The spectra also confirm a Compton shoulder of the He$?$ line complex for the first time. Both fluorescing and scattering spectral profiles indicate that the binary system is seen from the companion side during these observations. The flux ratio of the Compton scattering emission to the fluorescent line suggests substantial hydrogen depletion of the primary wind, expected from CNO-cycled hydrogen nuclear fusion gas.

Maryland Shared Open Access Repository (USMAI Consortium)
Affordable and clean energy
Openalex Percentile: Top 4%
Astrophysical Phenomena and Observations
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.