Observing Campaign #883: Photometry of DQ Tau needed tonight and tomorrow night

View here: Photometry of DQ Tau requested in support of multiwavelength observations

Abstract: Dr. Agnes Kospal (Konkoly Observatory) writes: “DQ Tau is being observed with the VLBA in the radio, JWST in the infrared, and Chandra in the X-ray. Four sets of observations are planned between now and March 4, 2025. We request optical photometric observations to monitor the brightness of DQ Tau in order to know its exact state of accretion during the VLBA, JWST, and Chandra observations.”

Justification: “DQ Tau is a young binary system consisting of two equal-mass T Tauri stars surrounded by a circumbinary protoplanetary disk. The two stars orbit each other on an eccentric orbit with a period of 15.8 days. During periastron, the mass accretion from the disk onto the stars have a peak, causing the brightening of the system. Although the brightenings are periodic with P=15.8 days, not all events have the same light curve shape: the strength and duration of the brightenings change from orbit to orbit, thus the need for contemporaneous monitoring. DQ Tau with its periodically changing accretion rate offers a unique opportunity to study how the disks react to variable irradiation, such as changes in its physical (temperature, emitting area) and chemical (molecular abundances) properties. The results of this research project will have important implications on disk evolution and planet formation, as the disk provides the material necessary to form the solid cores of planets and their atmospheres as well.”

Here is the original post from January 28: An observing campaign is starting on the T Tauri variable DQ Tau. We need CCD photometry of it tonight (January 28-29, 2025) and tomorrow night (Jan. 29-30) - BVRI is preferred, with V given highest priority. Multiple observations per night would be good, ideally with a cadence of 5 minutes during Jan 29 06:20 – 08:06 UT. According to the AAVSO International Database, DQ Tau was magnitude 13.62 V +/-0.025 on 2025 Jan. 08.9923 UT (T. Karlsson, Varberg, Sweden). Information on DQ Tau including coordinates is here in VSX. Finder charts with comparison stars may be created using the AAVSO’s Variable Star Plotter (VSP). Many thanks, and good observing - Elizabeth Waagen, AAVSO HQ

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I have added it to my observing program. However by 6h UT the star is already below the horizon from Chile.
Josch

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Thanks very much, Josch! Even if you can’t get observations during that window, knowing what it’s doing will be very helpful.

By pure chance I received a set of BVR images of DQ Tau right now. I have sent the results to you now. I got DQ Tau to 13.221V at 2025-01-28 21:28UT.

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Hi all,
Thanks so much for helping out! Elizabeth posted this announcement upon my request, so I’ll be checking the forum and answer questions if there’s any. I have an update now: the high cadence data would be needed between 4:50 - 6:40 UT, so a bit earlier than indicated above. Still not ideal for Chile, I know. But any data will be very helpful, I can always interpolate if necessary.
Agnes

I can do high cadence in B & V between 1:30 and 5:00 on the 29th UT (observing tonight until about 10 pm CST). I know this is a bit earlier than requested but hopefully it will be useful.

Should this be submitted to AAVSO or do you want the observations sent to you directly?

Bill

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Trying, but VSP has bad gateway. No chart. Shooting blind at the VSX coordinates.

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AAVSO is fine, thank you!

Taking data now, BVI every ~5 minutes. Fairly dim. Still no VSX chart available. I am shooting the VSX coordinates with a 24’ FOV.

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Here is ~4 hrs of BV data. I’m including a CSV file and an AAVSO extended format file. Also attaching a graph. The data is untransformed currently.

Nothing unusual happened. The star averaged 13.22 in V and 14.59 in B.

DQ_Tau.csv (1.8 KB)

AAVSO.txt (5.8 KB)

Bill

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Great, thank you!
Agnes

Bill, can you publish a chart so I can find the comps and make sure i am on target?

I am at airmass 1.5 and have maybe another 30 minutes to run.
If I have the right field, I should have data once VPHOT is back online.

Ray

Thanks Bill. I did find it on SkyMaps.org. Pretty sure I had the right field. But different comps. I am getting about the same V magnitudes that you have.
I could get it with MaxIM DL photometry but I’ll wait for VPHOT’s database to come back online tomorrow.

As VSP is down I cant check whether my new comp star sequence is actually needed. Therefore I will upload this new sequence anyway. If some of the existing sequence is effectively overwritten then these replacements will be newer and hopefully an improvement. New sequence has the colours requested in addition to several Sloan filter values.
Michael Poxon (YSO group / sequence team)

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Problem appears to be with the VSP form. Please fix this!!
If anyone requires comp star details just email me and I will send the .txt file that contains all the comp star details - which are useless as long as VSP is not working!
mikethestarman at gmail.com

Hi Bill, thank you for your photometry of DQ Tau! Please submit it to the AID using WebObs. Thanks! - Elizabeth

Hi Mike and everyone else, We apologize for the system slowdown and related timeouts of VSP. We are working on the causes of the slowdown and will have things back up to speed as soon as we can. In the meantime, thank you for your patience. Good observing, Elizabeth

Cheers. I uploaded the ‘new’ sequence this morning. Thought it was going to be clear tonight so I could actually observe DQ Tau but looking cloudy now. The great british weather strikes again!

Transform Applier via VPHOT is still broken.