IUE Ultraviolet Spectral Atlas of Standard Stars
|
Computer Sciences Corporation |
* "Normal" Stars
The observations, assembled here, were done mostly by Wu and his
collaborators. Only a small number of images were taken from
the IUE calibration programs and the other Guest Observers.
All observations were made in the low dispersion mode, with a
spectral resolution of about 6 Å. For stars with a spectral type
of F2 or earlier, both the short wavelength (1150-1975 Å) and
long wavelength (1975-3200 Å) spectral regions were observed,
while the short wavelength spectrum was generally not obtained
for stars later than F2. In order to maximize the signal-to-noise
(S/N) ratio, essentially all the spectra were taken in trail or
pseudo-trail mode. Additionally, many observations have a
complementary spectrum taken in the small aperture, such that
higher exposure levels can be achieved for the spectral regions
that tend to be underexposed.
Wu and his collaborators selected the candidate stars according
to the following criteria: no known variability or peculiarity;
not a member of a multiple system that has a companion that can
introduce non-negligible flux to the observed spectrum; reliable
MK spectral types and UBV photometry are available; low (or lower)
interstellar extinction; and bright enough to give good S/N ratio
at reasonable exposure times (generally 30 minutes or less), yet
faint enough to give reliable trail rates (about 10 arcsec/sec
or less). To provide additional cross checking against peculiarity
and variability in the candidate stars, many of the spectral
type and luminosity class combinations have two or more stars.
The observations provide a reasonably comprehensive
coverage of the HR diagram. Note that many
F, G, K dwarfs and giants have an appreciable number of observed
stars. This is intended to include a range of metallicity to
facilitate the modelling of the important main sequence turn-off
components in older stellar populations.
The observations for the pervious atlas (Wu et al. 1983,
1991, 1997) were made during the period from March 1980 to
September 1994. And the data presented in the three installments
were processed by different versions of the IUESIPS and reduced
by the software which was available in the IUE Data Analysis
Center at the time. Thus, the previous atlas is lacking in
internal consistency. Also, the noise characteristics, instrument
parameters, and calibration which directly relate to the accuracy
of the reported stellar fluxes, are better known now. The IUE
Project has developed the NEWSIPS pipeline processing system
which incorporates these latest improvements in the treatment
of the IUE data. The Project has essentially reprocessed all
the data with the NEWSIPS pipeline, and created the IUE Final
Archive. Therefore, the time is ripe for the production of a
new atlas, based on the data from the Final Archive, which will
have the uniformly processed data and significantly improved
accuracy for the stellar fluxes. For a detailed discussion of
the Final Archive and the recalibration of the IUE spectra,
see Nichols & Linsky (1996).
For the new atlas, selected high quality spectra of a star will
be merged to increase the S/N, and to repair spectral regions
contaminated by reseaux, cosmic ray hits and other blemishes.
* Spatial Distribution (476 "Normal" Stars)
Observations : Spatial Distribution (476 "Normal" Stars)
|
* Star Distribution in Spectral Types
Observations : Star Distribution in Spectral Types
* O
* B
* A
* F
* G
* K
* M
*
|
O Star |
VI |
V |
IV |
III |
II |
Ib |
Iab |
Ia |
If |
In |
m |
3 |
|
2 |
|
|
|
|
|
|
|
|
|
4 |
|
2 |
|
|
|
|
|
|
|
|
|
5 |
|
1 |
|
3 |
|
|
|
|
|
|
|
6 |
|
|
|
2 |
|
|
|
|
1 |
1 |
|
6.5 |
|
|
|
|
|
|
|
1 |
|
|
|
7 |
|
1 |
|
2 |
2 |
|
|
|
|
|
|
7.5 |
|
|
|
2 |
1 |
|
|
1 |
|
|
|
8 |
|
2 |
|
|
|
|
|
2 |
|
|
|
8.5 |
|
1 |
|
|
|
|
1 |
|
|
|
|
9 |
|
1 |
1 |
|
|
|
|
|
|
|
|
9.5 |
|
2 |
|
2 |
|
1 |
1 |
1 |
|
|
|
9.7 |
|
|
|
|
|
|
1 |
|
|
|
|
B Star |
VI |
V |
IV |
III |
II |
Ib |
Iab |
Ia |
If |
In |
m |
0 |
|
1 |
|
1 |
1 |
1 |
|
|
|
|
|
0.5 |
|
1 |
1 |
3 |
|
1 |
|
1 |
|
|
|
1 |
|
3 |
|
2 |
3 |
3 |
2 |
1 |
|
|
|
1.5 |
|
2 |
2 |
3 |
|
|
|
|
|
|
|
2 |
|
2 |
3 |
3 |
1 |
1 |
|
1 |
|
|
|
2.5 |
|
4 |
1 |
2 |
|
1 |
|
|
|
|
|
3 |
|
4 |
2 |
1 |
1 |
|
1 |
1 |
|
|
|
4 |
|
3 |
2 |
3 |
|
|
|
|
|
|
|
5 |
|
3 |
2 |
3 |
1 |
2 |
|
1 |
|
|
|
6 |
|
3 |
2 |
2 |
|
1 |
|
1 |
|
|
|
7 |
|
4 |
|
1 |
|
|
|
|
|
|
|
7 |
|
1 |
|
2 |
2 |
|
|
|
|
|
|
8 |
|
2 |
|
4 |
1 |
|
|
|
|
|
|
9 |
|
2 |
2 |
1 |
|
|
2 |
1 |
|
|
|
9.5 |
|
5 |
|
1 |
|
|
|
|
|
|
|
A Star |
VI |
V |
IV |
III |
II |
Ib |
Iab |
Ia |
If |
In |
m |
0 |
|
4 |
1 |
2 |
1 |
1 |
|
1 |
|
|
|
1 |
|
5 |
1 |
|
|
|
|
1 |
|
|
1 |
2 |
|
|
|
|
|
|
|
1 |
|
|
|
3 |
|
6 |
|
2 |
1 |
|
|
|
|
|
1 |
4 |
|
1 |
|
|
|
|
|
|
|
|
|
5 |
|
2 |
1 |
1 |
1 |
1 |
|
|
|
|
|
6 |
|
|
1 |
|
|
|
|
1 |
|
|
|
7 |
|
1 |
4 |
|
1 |
|
|
|
|
|
|
8 |
|
1 |
|
|
|
1 |
|
|
|
|
|
9 |
|
|
|
1 |
|
|
|
|
|
|
|
F Star |
VI |
V |
IV |
III |
II |
Ib |
Iab |
Ia |
If |
In |
m |
0 |
|
2 |
1 |
2 |
|
1 |
|
|
|
|
|
1 |
|
|
|
2 |
2 |
|
|
|
|
|
|
2 |
|
2 |
1 |
3 |
|
1 |
|
1 |
|
|
|
3 |
|
2 |
1 |
2 |
|
|
|
2 |
|
|
|
4 |
|
2 |
2 |
2 |
|
|
|
|
|
|
|
5 |
1 |
6 |
2 |
2 |
|
2 |
|
|
|
|
|
6 |
|
7 |
3 |
1 |
|
1 |
|
|
|
|
|
7 |
|
7 |
2 |
|
|
2 |
|
|
|
|
|
8 |
|
6 |
4 |
|
|
2 |
1 |
1 |
|
|
|
9 |
|
7 |
|
|
|
|
|
|
|
|
|
G Star |
VI |
V |
IV |
III |
II |
Ib |
Iab |
Ia |
If |
In |
m |
0 |
|
10 |
4 |
2 |
1 |
2 |
|
|
|
|
|
1 |
|
5 |
1 |
|
1 |
1 |
|
|
|
|
|
2 |
|
8 |
1 |
|
|
2 |
|
1 |
|
|
|
3 |
|
2 |
|
|
1 |
1 |
|
|
|
|
|
4 |
|
|
|
2 |
1 |
1 |
|
|
|
|
|
5 |
|
5 |
1 |
2 |
1 |
1 |
|
|
|
|
|
6 |
|
2 |
|
|
|
|
|
|
|
|
|
7 |
|
|
|
2 |
|
|
|
|
|
|
|
8 |
|
7 |
3 |
7 |
1 |
1 |
|
|
|
|
|
9 |
|
|
|
3 |
1 |
|
|
|
|
|
|
K Star |
VI |
V |
IV |
III |
II |
Ib |
Iab |
Ia |
If |
In |
m |
0 |
|
4 |
1 |
11 |
|
2 |
|
|
|
|
|
1 |
|
3 |
3 |
2 |
1 |
1 |
|
|
|
|
|
2 |
|
2 |
1 |
9 |
3 |
1 |
|
|
|
|
|
3 |
|
2 |
|
4 |
2 |
1 |
|
|
|
|
|
4 |
|
|
|
4 |
|
1 |
|
|
|
|
|
5 |
|
1 |
|
3 |
|
|
1 |
|
|
|
|
7 |
|
1 |
|
4 |
|
1 |
|
|
|
|
|
M Star |
VI |
V |
IV |
III |
II |
Ib |
Iab |
Ia |
If |
In |
m |
0 |
|
|
|
4 |
|
|
|
|
|
|
|
0.5 |
|
1 |
|
1 |
|
|
|
|
|
|
|
1 |
|
2 |
|
|
|
|
|
|
|
|
|
2 |
|
|
|
4 |
|
1 |
|
1 |
|
|
|
3 |
|
1 |
|
4 |
1 |
|
|
|
|
|
|
3.5 |
|
|
|
1 |
|
|
|
|
|
|
|
4 |
|
|
|
|
2 |
|
|
|
|
|
|
4.5 |
|
|
|
2 |
|
|
|
|
|
|
|
5 |
|
|
|
1 |
|
|
|
|
|
|
|
6 |
|
|
|
1 |
|
|
|
|
|
|
|
7 |
|
|
|
1 |
|
|
|
|
|
|
|
jinger@stsci.edu
last updated: Jan. 2003/b>