New variable star? in Lyr (Sieber)

(vsnet 672)

I picked up a star on my ccd which I was unable to verify on my starchart as of 07/05/96. The star coordinates are: 19h 17m 04.5s 33d 03m 58s in Lyr. The approximate magnitude is 11.2 and is non-red The object is 1.2 min south of gsc2657:2581 I'm currently using a program called MEGASTAR @ 2000.00 with mag cutoff set at 13.0. Is there someone who could check a different chart in case its a simple omission on my chart. Thank You.
D.J. Sieber

Comment by Skiff

(vsnet 673)

I just used the DSS in SkyView... look at an area around the position you mention. Exactly at your position is a fairly faint star (not in the GSC or in the UJ1.0 disk) about mag. 16 in the red. Does your CCD frame show a fairly bright and moderately-close pair immediately south of your suspect star? If so, then I think you have found a new variable of some kind. As usual, more data are required. Try to get some frames each night in at least two filters until the timescale of the variations is clear. It is probably a long-period variable of some kind, so after a few nights, you culd probably cut back to observing once a week or ten days to keep up with it. But for now you want to hit it fairly hard.

I looked in SIMBAD, but there are no variables listed, nor IRAS sources or other suspicious objects.

Hope this helps. I'll post this info to the vsnet group in a moment. \Brian

Visible on Vehrenberg's Atlas Stellarum (Bouma)

(vsnet 674)

Dear Sirs,

I checked the Seeber suspect in Vehrenberg's Atlas Stellarum, and found an object of (approximately) magnitude 13.2 at the suspect's position (using nearby GSC magnitudes for comparison). The Vehrenberg plate was exposed on 1967 September 2 from 19:54 to 20:24h UT. If this Vehrenberg object (missing from GSC), Seeber's object, and Skiff's DSS candidate are one and the same object, it may be a UGem type variable (if we are lucky), and worth close monitoring by both visual and CCD 0bservers. I'll have a go at it tonight (if the clouds disappear)!


Reinder Bouma

Reinder J. Bouma          email:
Bekemaheerd 77            phone: +31 (0)50-5418227
9737PR  Groningen
The Netherlands

Spectrum - no emission line object

(vsnet 677)


John Thorstensen sent me the following message in regard to the possible Sieber variable star. Clearly this is not an emission-line object, such as a dwarf nova or ordinary nova---but then again it is not obvious that what is evidently a G or K star should be a strong variable.
\Brian (Brian Skiff)


Date: Sat, 6 Jul 96 07:00:13 MST
From: (Visitors To MDM)
Subject: Sieber's object ...

Dear Dr. Skiff,

Would you please post this to VSNet? I don't know how and I gotta get some sleep one of these days:

J. R. Thorstensen (Dartmouth College) took a 6-minute spectrum of the star on Sieber's position using the MDM 2.4-meter telescope at HJD 2450270.7676; although the signal-to-noise ratio was modest, the spectrum would have shown the strong emission lines characteristic of dwarf novae at minimum light had they been present. There were no emission lines, but there were hints of absorption at NaD and at Mg b, suggesting a spectral type of G or K. The brightness on the TV guider appeared comparable to the Digitized Sky Survey, though this comparison was not done carefully.

Thanks ....
			John Thorstensen

To be continued ...

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