Alert Notice 776: Coverage of 6 YSOs needed in May for HST observations

April 29, 2022

AAVSO Forum threads (scroll to the bottom of a thread for latest posts):
- Campaigns and Observing Reports: https://www.aavso.org/odysseus-ix-southern-targets-may-01
- Young Stellar Objects (YSO): https://www.aavso.org/odysseus-ix-southern-targets-may

Please subscribe to these threads if you are participating in the campaign so you can be updated by the astronomer and by HQ. Join in the discussion or ask questions there!

Dr. Frederick Walter (Stonybrook University) requests AAVSO observers' assistance in monitoring six T Tau stars in support of HST observations scheduled for May 2022. As part of the HST ULLYSES program (which is part of the larger ODYSSEUS program), the HST is scheduled to obtain UV spectra of these accreting T Tauri stars. It would be helpful to have BVRI photometry for them in order to help interpret the UV spectra.

The first four stars will be observed during the first week of May, so coverage of them is needed beginning NOW; please see the table for exact dates and times. The other two stars will be observed a little later in May as shown in the table below. The exact times for Sz 84 and Sz 97 will be announced in the forum threads above when they have been scheduled by the HST team.

Dr. Walter, who thanks AAVSO observers for their contributions to this program to date, provides the following information:

Note: Time followed by a * should be observable from the Western hemisphere simultaneously with the HST observations.

If you can observe these targets, please obtain digital BVRI photometry on the dates specified. It is important to get single BVRI sequences each night, but longer sets of data would be useful if they can be obtained simultaneously with the HST observations. There will not be any TESS observations.

Observers should note that for SSTc2d J161344.1-373646, B comp stars are not available. Some of the other targets may have few B comps. Please do your best to obtain as much of the multicolor photometry requested with the sequences provided.