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Optical data on V2492 Cyg needed to support X-ray obs

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Optical data on V2492 Cyg needed to support X-ray obs

(I posted this message in the "Young Stellar Object" forum, but it appears to have attracted no attention for several days ... and as time is running out, this forum seems appropriate)

The young stellar variable V2492 Cyg (J2000 = 20 51 26.228 +44 05 23.88) has recently entered a bright phase in the optical, reaching V = 13.5 in early March. A team on which I'm a member has triggered a target-of-opportunity program for X-ray observations with XMM-Newton, which will observe the star on April 18-19, 2017.

One of my colleagues, Nicholas Grosso, has requested an AAVSO alert for this object over the next month. I'll post a followup on this forum if and when such an alert is granted, to link it here.

The basic idea is that we would like to monitor the behavior of this object in the optical (and near-IR, if possible) over the next two months, so that we can compare the X-ray and optical variations. It may be possible to rule out some models for the eruptive nature of this and similar objects if we see correlations (or the lack of correlations) in the light curves.

A single measurement in any standard filter (UBVRI or Sloan in the optical, JHK in the near-IR) once per night, or once per 2-3 nights, would give us the information we need. The object is visible for only an hour or two before dawn, so this might be inconvenient for some observers.

Thank you very much in advance for your help. Please ask questions in this forum topic, and I'll do my best to answer them.

lmk's picture
Poor elongation

Hello, Part of the reason may be it is close to the sun and inconvenient for ground based observations. I have noticed this is/was a common issue with many campaign requests in the past, the objects are frequently in a poor solar elongation. Of course, it doesn't matter for satellite observations, but if ground based collaboration is requested, I do wonder why more objects are not better selected opposite the solar area?




Why choose a star so close to the Sun?

That's a good question.  I'm an observer myself, who does enjoy getting some sleep now and then, so I understand the issues :-)


In this particular case, the choice of "when to schedule" was made by the star, not by us.  The star recently erupted into a high state of unusual activity -- perhaps because some material is currently falling onto the accretion disk, or perhaps because of some other effect.  We want to observe the phenomenon to understand it better, so we _have_ to observe now.  If we wait for a few months, the outburst will very likely have ended.


weo's picture
V2492 Cyg observations

Hi Michael,

An AAVSO Alert Notice announcing an observing campaign is in the works for V2492 Cyg, and will be announced today or tomorrow.

Best wishes,

Elizabeth Waagen

Please send questions or comments to the campaign thread

Let's collect all discussion of V2492 Cyg on the campaign thread, since most people will probably find out about it via the Alert Notice. Go to:

I'll be watching that forum closely, and will try to answer any questions I can. Feel free to ask away, and clear skies!

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