ODYSSEUS VII. 2 southern targets to start the new year

American Association of Variable Star Observers (AAVSO)
Thu, 01/20/2022 - 23:20

As part of the HST ULLYSES program (see earlier threads for details), the HST is scheduled to obtain UV spectra of two accreting T Tauri stars next week. It would be helpful to have BVRI photometry for them in order to help interpret the UV spectra. These are southern targets, in the eta Cha association (declination -78 deg).

The targets are:

   EN Cha (RECX 9) 08 44 16.64 -78 59 08.9 (J2000)   V=14.75 (0.38)
    HST schedule:    25 Jan 2022 21:25:54 - 26 Jan 2022 03:21:34  UT

   EK Cha (RECX 5) 08 42 27.30 -78 57 48.5 (J2000)   V=15.2 (0.03)
    HST schedule:    27 Jan 2022 19:27:39 - 28 Jan 2022 01:21:45  UT

If you can observe these targets, please obtain digital BVRI photometry now through Jan 27 (EN Cha) or Jan 29 (EK Cha). 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.

The stars are about 5 arcmin apart on the sky. There is a nice bright galaxy (ESO 18-13; R ~ 13mag) nearby.

Thank you for all the contributions you have made to this program to date.


Vereniging Voor Sterrenkunde, Werkgroep Veranderlijke Sterren (Belgium) (VVS)
Both stars

I will try to take images in BVRI for both stars tonight and the coming nights weather permitting.