Discovery of a new X-ray burst/millisecond accreting pulsar, HETE J1900.1-2455

Motoko Suzuki, Nobuyuki Kawai, Toru Tamagawa, Atsumasa Yoshida, Yujin E. Nakagawa, Kaoru Tanaka, Yuji Shirasaki, Masaru Matsuoka, George R. Ricker, Roland Vanderspek, Nat Butler, Donald Q. Lamb, Carlo Graziani, Graziella Pizzichini, Rie Sato, Makoto Arimoto, Jun'ichi Kotoku, Miki Maetou, Makoto Yamauchi

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


A class of low-mass X-ray binary sources is known to be both X-ray burst sources and millisecond pulsars at the same time. A new source of this class was discovered by High Energy Transient Explorer 2 (HETE-2) on 2005 June 14 as a source of type-I X-ray bursts, which was named HETE J1900.1-2455. Five X-ray bursts from HETE J1900.1-2455 were observed during the summer of 2005. A time-resolved spectral analysis of these bursts has revealed that their spectra are consistent with the blackbody radiation throughout the bursts. The bursts show an indication of radius expansion. The bolometric flux remained almost constant during the photospheric radius expansion, while blackbody temperature dropped during the same period. Assuming that the flux reached the Eddington limit on a standard 1.4 solar-mass neutron star with a helium atmosphere, we estimate the distance to the source to be ∼ 4 kpc.

Original languageEnglish (US)
Pages (from-to)263-268
Number of pages6
JournalPublications of the Astronomical Society of Japan
Issue number1
StatePublished - 2007
Externally publishedYes


  • Stars: neutron
  • Stars: pulsars: individual (HETE J1900.1-2455)
  • X-rays: bursts

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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