As part of the HST ULLYSES program (see earlier threads for details), the HST is scheduled to obtain UV spectra of a number of accreting T Tauri stars in the coming weeks. It would be helpful to have BVRI photometry for them in order to help interpret the UV spectra. These are southern targets, in the Sco/Lupus and Chamaeleon clouds.
The targets are:
SSTC2DJ161344.1-373646
16 13 44.101 -37 36 46.26 (J2000) g=15.9; R=16.3 (not in VSX)
Start time: 02 May 2022 13:38:02 End time: 03 May 2022 06:23:36 *
Please try to observe the nights of April 28-May 2
-------------------
VZ Cha
11 09 23.774 -76 23 20.86 V=12.94 VSX: 12.1-14.6 V
Start time: 05 May 2022 02:40:23 End time: 05 May 2022 03:30:16 *
Start time: 05 May 2022 19:31:06 End time: 06 May 2022 04:16:25 *
Start time: 06 May 2022 17:44:39 End time: 07 May 2022 04:05:51 *
Please try to observe the nights of April 30-May 7
-------------------
WZ Cha
11 10 53.321 -76 34 32.06 V=15.48 VSX: 14.9-16.68 B
Start time: 04 May 2022 18:10:21 End time: 05 May 2022 02:28:13 *
Please try to observe the nights of April 29-May 5
-------------------
V1279 Sco
16 08 22.494 -39 04 46.43 V=13.66 VSX: 11.8-15 g
Start time: 03 May 2022 13:27:10 End time: 04 May 2022 06:11:11 *
Please try to observe the nights of April 29-May 4
--------------------
Sz 84
15 58 02.520 -37 36 02.73 G=14.4, B=14.3 (not in VSX)
On long term plan May 10-14; exact times not yet known
Please try to observe the nights of May 7-14
--------------------
Sz 97
16 08 21.804 -39 04 21.49 V=14.61 (not in VSX)
On long term plan May 10-14; exact times not yet known
Please try to observe the nights of May 7-14
--------------------
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.
Thank you for all the contributions you have made to this program to date.
Not all of the targets on the May HST ULLYSES program (in the post above) are in VSX or have sequences. That work is being done today and in the next few days. If a sequence does not exist when you observe a target, please hang on to your images, and when a sequence is available it will be announced here. Many thanks.
Good observing,
Elizabeth
All the 'new' stars now have sequences - but please bear in mind that virtually all are in areas that have strong reddening due to the Interstellar Medium (ISM), so try not to be alarmed by the occasional high B-V values where we have them! Most of the contribution to these values comes from the ISM, not the stars themselves. The campaign calls for observations in B but again this was not achievable for many of these objects as it was necessary to use Gaia as a source because (1) Some are faint beyond the reach of APASS (2) They are too far South for PanStarrs - and Gaia does not provide B values.
I have communicated with the PI on the campaign explaining the above, and he has okayed the sequences but will bear these facts in mind when the campaign resolves.
Other sources of photometry in the south are the Pan-STARRS 'refcat2' and SkyMapper, which show Sloan photometry up to about mag 10. You can access refcat2 readily using VizieR as item j/apj/867/105, where as SkyMapper is best queried through its own Web server:
https://skymapper.anu.edu.au/cone-search/
For Sloan griz ---> BVRI, the transformations of Kostov & Bonev are probably the best:
https://ui.adsabs.harvard.edu/abs/2018BlgAJ..28....3K/abstract
...through strictly speaking these apply to the Pan-STARRS system, not SkyMapper, which is very slightly different at the couple percent level (calibration issues still getting worked out). I suggest comparing results from the K&B linear and quadratic transformations to see how well they agree.
\Brian
AAVSO Alert Notice 776 announces a campaign on 6 Young Stellar Ojects (YSO) in Sco, Cha, and Lup beginning immediately. Please see the Notice for details and observaing instructions.
There are threads for this campaign under the following forums:
- 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. Join in the discussion or ask questions there!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
Added all targets to my observing schedule from tonight onwards.
Regards,
Josch