TENMA measured energy spectra of various X-ray stars accurately using the high-energy resolution of gas-scintillation proportional counters. The figure shows an example of the energy spectra obtained from the X-ray pulsar Vela X-1. An emission line from cold iron is clearly detected at 6.4 keV.
|Name (pre-launch in parentheses)||TENMA (ASTRO-B)|
|International Designation code||1983-011A|
|Objectives||High-resolution spectroscopy of X-ray stars and observations of gamma-ray bursts|
|Launch Date||February 20, 1983|
|Launch Location||Kagoshima Space Center (Uchinoura)|
|Shape||Square pillar, 94cm diameter, 89.5cm high
Four solar paddles
|Orbital Altitude||Perigee 497km, Apogee 503km|
|Type of orbit||Near circular|
|Orbital Period||94 min.|
|Scientific Instruments||Gas Scintillation Proportional Counter
X-ray Focusing Collector
Hadamard X-ray Telescope
|End of Operation||December 17, 1988|
|Reentered Date||January 19, 1989|
|Operation||After launch, the solar paddles were deployed, and initial checks, attitude control with magnetic torquers and spin control were conducted smoothly. Later, attitude control was changed to free-spin mode because trouble with the momentum wheel increased satellite rotation. A problem was found in the power system in July 1984, but observations of X-ray stars continued because the mission instruments remained normal.|
|Results||1.Discovered hot plasma of several tens of millions of degrees located along the Galactic plane.
2.Discovered the iron absorption line in the energy spectra of X-ray bursts, which was red-shifted in the strong gravitational field of the neutron star.
3.Identified X-ray emission regions in low-mass X-ray binaries as the surface of the neutron star and the accretion disk.
4.Discovered that the cold, i.e., neutral iron is responsible for the emission line from X-ray pulsars.