[vsnet-alert 4555] XTE J1118+480: astrometry from DSS plates

["Bjorn H. Granslo" <b.h.granslo@astro.uio.no>]

Dear colleagues,

Following the comments by H. Yamaoka [vsnet-alert 4508, 4543, 4546]
and B. Skiff [vsnet-alert 4540, 4544, 4545] I have investigated the
available DSS plates that cover the field around XTE J1118+48.0.

Digitzed images of the plates were obtained from
http://archive.stsci.edu/cgi-bin/dss_plate_finder

From small extracts (5' x 5') of the epoch 1995.233 and 1953.187
plates I obtained the following positions of the possible progenitor
to XTE J1118+48.0, called object X (USNO-A2.0 1350-07924726), and
two nearby stars of mag. ~19 (A and B, not included in the USNO-A2.0
catalogue).

Survey Name       Epoch     Object    R.A. (2000.0) Decl.
POSS-II Red       1995.233    X    11h18m10s.83  +48o02'13".3
POSS-E Red Plate  1953.187    X    11h18m10s.83  +48o02'12".7

POSS-II Red       1995.233    A    11h18m11s.95  +48o02'19".9
POSS-E Red Plate  1953.187    A    11h18m11s.82  +48o02'18".6

POSS-II Red       1995.233    B    11h18m09s.90  +48o02'34".3
POSS-E Red Plate  1953.187    B    11h18m09s.91  +48o02'33".8

The positions were deduced by using six USNO-A2.0 stars, with mean
residuals of 0".8 and 0".3 for the 1995 and 1953 plates,
respectively.

From this I conclude that it is highly probable that USNO-A2.0
1350-07924726 is the progenitor to XTE J1118+48.0. This object
has shown no clear proper motion since 1953. However, object A
appears to haved moved somewhat (by ~2") during this time interval.

The apparent progenitor appeared faint (mag. ~18.5 or fainter) on
all DSS images.

                                   Yours sincerely,
                                   Bjorn H. Granslo

VSNET Home Page

Return to Daisaku Nogami

---

vsnet-adm@kusastro.kyoto-u.ac.jp