Alert Notice 780: Observations needed for four YSO targets being observed with HST

June 14, 2022

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

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Dr. Frederick Walter (Stony Brook University) requests AAVSO observers' assistance in monitoring four T Tau stars in support of HST observations scheduled for June 16 - 19 -- THIS WEEK. 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.

All four stars will be observed during this week, so coverage of them is needed beginning NOW; please see the table for exact dates and times.

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

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.