Part V of the ODYSSEUS pre-main sequence star program starts this month.
ODYSSEUS is an international collaborative campaign to understand the processes
involved in the formation of low mass stars, their circumstellar disks, and
their planets, via the time-variability of these systems. Please read other
forum notes on this program for more details.
The HST will monitor the pre-main sequence star GM Aur for 3 stellar rotation
periods (about 18 days) starting 13 October. It is being observed simultaneously with TESS.
If you can, please obtain CCD BVRI observations of this star at least nightly
during this campaign (Oct 13-Nov 1). If you can observe during the HST windows, please do so.
Because we will have TESS photometry, your primary
contribution will be the photometric colors. Please try to obtain 1% photometry
(0.01 mag uncertainty) so we can compute colors to better than 2%. It is the
color changes that will help us determine the cause for any changes in the
UV line fluxes, or in the overall brightness.
Thank you for your contributions to the earlier parts of the ODYSSEUS campaign.
Your participation in this campaign is a big part of its success.
Please upload any data you get to the AAVSO database. Thanks in advance
for your contributions to this campaign.
GM Aur particulars:
Position: 04 55 10.98 +30 21 59.4 (J2000).
Magnitude: V~12.2
In 2019 TESS observations GM Aur varied by about 0.05 mag on timescales of a few days.
Note that GM Aur is within 28 arcsec of 2MASS J04551015+3021333, a star of
comparable brightness (G=11.3), of which little is known. Since this star will
be blended with GM Aur in the TESS images (21 arcsec pixels), please also
extract photometry for this star. We will need to know how it is varying (if it is) in order to assess GM Aur's variability.
The near-IR colors and the GAIA parallax suggest that this star is a background giant.
2MASS J04551015+3021333
Position: 04 55 10.16 +30 21 33.2 (J2000).
Magnitude: G=11.3
The current HST schedule is:
Date Start (UT) End
13 Oct 2021 11:54:10 13 Oct 2021 12:46:38
15 Oct 2021 06:46:59 15 Oct 2021 07:39:27
16 Oct 2021 16:08:03 16 Oct 2021 17:00:31
17 Oct 2021 20:46:03 17 Oct 2021 21:38:31
19 Oct 2021 14:23:24 19 Oct 2021 16:05:31
20 Oct 2021 21:48:12 20 Oct 2021 22:40:40
22 Oct 2021 15:03:54 22 Oct 2021 15:56:22
23 Oct 2021 22:49:33 23 Oct 2021 23:42:01
25 Oct 2021 17:42:02 25 Oct 2021 18:34:30
27 Oct 2021 06:13:24 27 Oct 2021 08:13:16
28 Oct 2021 15:34:10 28 Oct 2021 16:26:38
30 Oct 2021 00:54:55 30 Oct 2021 01:47:23
AAVSO Alert Notice 756 announces a campaign on the T Tau star GM Aur in support of HST and TESS observations underway through the end of October. Please see the notice for details and observing instructions.
There are threads for this campaign under the following forums:
- Campaigns and Observation Reports: https://www.aavso.org/odysseus-v-photometry-gm-aur-support-hst-and-tess-01
- Young Stellar Objects: https://www.aavso.org/odysseus-v-photometry-gm-aur-support-hst-and-tess
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!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
Per Fred Walter's suggestion, I have reduced data for the GM Aur companion GSC 2387-0265 = 2MASS J04551015+3021333 in a sample of images from my monitoring of this field in 2017 and 2020. The data were taken using the Lowell robotic 0.7-m telescope + V filter. The star is stable at the few-millimag level across the three-year interval when measured against five similar field stars (rms scatter 0.006 mag in the sample). The APASS DR9 V mag of 11.87 is about right.
\Brian
The HST observing schedule for GM Aur is:
Date Start (UT) End
13 Oct 2021 11:54:10 13 Oct 2021 12:46:38
15 Oct 2021 06:46:59 15 Oct 2021 07:39:27
16 Oct 2021 16:08:03 16 Oct 2021 17:00:31
17 Oct 2021 20:46:03 17 Oct 2021 21:38:31
19 Oct 2021 14:23:24 19 Oct 2021 16:05:31
20 Oct 2021 21:48:12 20 Oct 2021 22:40:40
22 Oct 2021 15:03:54 22 Oct 2021 15:56:22
23 Oct 2021 22:49:33 23 Oct 2021 23:42:01
25 Oct 2021 17:42:02 25 Oct 2021 18:34:30
27 Oct 2021 06:13:24 27 Oct 2021 08:13:16
28 Oct 2021 15:34:10 28 Oct 2021 16:26:38
30 Oct 2021 00:54:55 30 Oct 2021 01:47:23
Please see the first entry in this thread for particulars.