RASSGIANT - RASS Giants & Supergiants Cat.
The HR number of the star in the Yale Bright Star Catalog.
The right ascension of the star in the selected equinox, i.e., the optical position. This information was not in the original version of this catalog but was added by the HEASARC using the co-ordinates listed in the online version of the Bright Star Catalog.
The declination of the star in the selected equinox, i.e., the optical position. This information was not in the original version of this catalog but was added by the HEASARC using the co-ordinates listed in the online version of the Bright Star Catalog.
The galactic longitude of the star.
The galactic latitude of the star.
The HD number of the star.
The commonly used constellation-based (Bayer or Flamsteed) name for the star, if one exists.
The Johnson V magnitude of the star (taken from the BSC).
The Johnson (B-V) color index of the star (taken from the BSC).
The spectral classification (spectral type + luminosity class) of the star, usually on the MK system (a few of the entries are on the old Harvard system where lower case 'g' means giant luminosity class), as taken from the BSC.
A flag indicating the binary status of the star, using the following categories:
S: single star VB: visual binary (if a companion within 90" separation is known) SB: spectroscopic binary (as given in the BSC) RS: RS CVn system (usually also SB) B: other binary (composite spectrum) CV: cataclysmic companion (HR 4765 = 4 Dra) SYMB: symbiotic star (HR 8992 = R Aqr)
The effective exposure time in seconds for the X-ray data.
The mean PSPC count rate in counts per second.
The error in the mean PSPC count rate in counts per second.
The likelihood significance Li for the existence of the X-ray source: Li = -ln(1-P), where P is the existence probability. The minimum likelihood for sources in the current catalog is 7, corresponding to P = 99.9 percent.
The offset in arcseconds between the X-ray and optical positions. The maximum offset accepted in the current catalog is 90 arcseconds. Given the 150,000 total number of RASS X-ray sources and the 3839 positions of BSC giants and supergiants examined, 27.4 out of the 450 `detections' listed here are expected to be chance coincidences. If a maximum offset of 60 arcseconds is permitted, the number of chance coincidences drops to 12.2.
The hardness ratio HR for the PSPC X-ray source, where HR = (H-S)/(H+S), H is the source counts in the hard (0.5 - 2.0 keV) passband of the PSPC, and S is the source counts in the soft (0.1 - 0.4 keV) passband of the PSPC. For a few sources which were not detected in the soft passband, the hardness ratio is is set to +1.0 by definition.
The error E(HR) in the hardness ratio HR for the PSPC X-ray source, calculated from the expression:
E(HR) = 2 * (S+H)**-1.5 * (S*H)**0.5
The apparent X-ray flux in the full (0.1 - 2.4 keV) PSPC bandpass in units of erg s**-1 cm**-2.
The logarithm of the X-ray to bolometric flux ratio.
The HEASARC browse classification for the star, as constructed from its spectral classification (the parameter spect_type).