Lew's Suspected Variable

Feb. 21, 1999.

The suspected variable is not bright (as first thought), but appears to be variable nonetheless

Near the field of AQ Eridani, a dwarf nova, one of the charted stars seemed brighter through the CCD camera than on the chart and other information available. A green filter (of unknown properties in the IR) was used.

The GSC information on the star:
GSC 4758:506 (Stellar) Magnitude:15.2 RA:05h 05m 37.2s Dec:-03d 59' 11" Epoch 2000.
South is up in the discovery image. The suspected variable is 12.5 arc min NW of AQ ERI and is shown on the current AAVSO (d) & (e) charts.

Differential photometry using the bright star at the top of the frame indicates the possible variable is at magnitude 9.25 on the instrumental pseudo V system, taking the V value for the reference star (GSC 4758:82) to be V=9.84.
Arne Henden then of the US Naval Observatory in Flagstaff reported his data and Lew inserts his measurements ( shown in italics), the photometry by Brian Skiff and other observers' visual observations (color)

Identification HJD V B-VObserver
Tycho star (4758-82):
Used as a comparison star
51195.6767 9.689 0.711Arne Henden
51202.7094 9.730 0.702Arne Henden
51220.7056 9.694 0.698Arne Henden
Lowell Observatory P.E. V 51222.7 9.730 0.68Brian Skiff

Observations of Lew's Star

Visual obs.51192.31913.7Transformed from
vis. obs. 14.2
V = v - 0.2(B-V)
Jan Hers
Lew's star (4758-506): 51195.6767 13.547 2.344Arne Henden
51202.7094 13.532 2.361Arne Henden
Lew's measured V
(not flat field)
51211.6583 13.45 not seen
in blue light
51220.7085 13.340 2.327Arne Henden
Lew's star
Visual obs.
51223.550713.5Transformed from
vis. obs. 14.0
V = v - 0.2(B-V)
Miroslav Komorous
CCDV 51229.652 13.20 Lew
CCDV51515.74 13.59 Lew
CCDV51537.75 13.65 Lew

and "Bottom line: his star is quite red and since it seems to be much fainter than Lew was finding, it sounds quite reasonable that Gary's (Gary Walker, AAVSO CCD Committee Chairman) suggestion of a red leak is the answer." and "So, Lew, it looks like your star *is* variable."
Lew acknowledges and thanks Arne, Gary and Brian Skiff of Lowell Observatory for valuable guidance and reference information. It is important to note that the green filter evidently passed a large amount of IR. BVR&I Filters matching the UBVRI system were obtained from Schuler Astroimaging Systems.

New Images in 4 colors!




Infra Red

Not visible!
(and a bit
Faint, but there
BrightVery bright in IR
Here's a cheesy
false color image
of it using
VR&I as BG&R.
Here's the DSS
image of it.
The DSS credit image is thanks to NASA! Based on photographic data obtained using The UK Schmidt Telescope. The UK Schmidt Telescope was operated by the Royal Observatory Edinburgh, with funding from the UK Science and Engineering Research Council, until 1988 June, and thereafter by the Anglo-Australian Observatory. Original plate material is copyright (C) the Royal Observatory Edinburgh and the Anglo-Australian Observatory. The plates were processed into the present compressed digital form with their permission. The Digitized Sky Survey was produced at the Space Telescope Science Institute under US Government grant NAG W-2166.
The subject star is 12.5 arc min NW of AQ ERI and is shown on the AAVSO (d) & (e) charts. A copy of the (Copyright AAVSO 1997) e chart is shown below with the variable marked "var?" While the star may not be variable, it is bright in the near IR.

Lew wishes to extend his thanks to those who worked on this star during the investigation including Arne Henden, Brian Skiff, Gary Walker, Jan Hers, Berto Monard, Chuck Scovil and Jerry Hudson.
The original AAVSO chart may be obtained from AAVSO's wabsite (www.AAVSO.org)


Photos and text (c) 1998, 2010 Lewis M. Cook The anomalous brightness of the star in the visual + IR was first posted on January 10, 1999.