AAVSO: American Association of Variable Star Observers
Login

Proposal #295

Proposer (2092) Michael Heald (msheald@hotmail.com) obscode: HMH
Assigned To(3663) Dirk Terrell
Date SubmittedDec. 2, 2022
StatusAllocated
PriorityNormal
Proposal

Target: UCAC4 457-001970

Proposal: To refine the period of EA variable UCAC4 457-001970, identified as 2.46796 in VSX.

Target: UCAC4 457-001970 [J2000.0: 01 31 37.38 +01 18 58.1  (22.90575 +1.31614)]

Reason: Less than 165 observations are in the AAVSO database, none of sufficient frequency to identify the target's light curve or period.

V Magnitude in VSX: 15.26 to 15.42. I magnitude estimate in LCG: 14.2

A clear filter can be used for this project for the period and amplitude identification since that would yield the best SNR with the shortest integration time. However, a V filter and/or I filter can be used (perhaps with the Takahashi Epsilon 180 f2.8 systems) in order to obtain additional information, but at increased integration times.

I estimate that one image every 30 minutes each evening for 5 days from astronomical twilight to the setting of the target should give sufficient information to allow a light curve determination with reasonable accuracy.

Targets
Target RA (H.HH) Dec (D.DD) Magnitude Telescope Observation Frequency Expiration Date Proprietary Term
UCAC4 457-001970 22.905750 1.31616 15.42–15.26 MPO61 June 11, 2023 No

Comments

(3663) Dirk Terrell — Dec. 8, 2022, 4:22 p.m.

Although the astrophysical potential for a system like this is pretty low, the TAC approves it and recommends that the 1.8 hour eclipses be covered with continuously when they happen and the out of eclipse part of the light curve can be observed once per night. Given how faint it is, one of the larger telescopes might provide better data but it is certainly doable with the BSMs.

(4726) Kenneth Menzies — Dec. 8, 2022, 5:41 p.m.

Mike:

Can you estimate a few potential TOMs for the target so we could actually run a time series around a potential eclipse rather than 30 minute images for a long period of time?

(2092) Michael Heald — Dec. 11, 2022, 9:04 p.m.

Here is the information in VSX. Best regards.

Mike

Ephemeris for UCAC4 457-001970 (HJD/UT)
Epoch Start Mid End

2459918.208 04 Dec 2022 16:06 04 Dec 2022 17:00 04 Dec 2022 17:53
2459920.676 07 Dec 2022 03:20 07 Dec 2022 04:13 07 Dec 2022 05:07
2459923.144 09 Dec 2022 14:34 09 Dec 2022 15:27 09 Dec 2022 16:21
2459925.612 12 Dec 2022 01:48 12 Dec 2022 02:41 12 Dec 2022 03:34
2459928.080 14 Dec 2022 13:02 14 Dec 2022 13:55 14 Dec 2022 14:48
2459930.548 17 Dec 2022 00:16 17 Dec 2022 01:09 17 Dec 2022 02:02
2459933.016 19 Dec 2022 11:29 19 Dec 2022 12:23 19 Dec 2022 13:16
2459935.484 21 Dec 2022 22:43 21 Dec 2022 23:37 22 Dec 2022 00:30
2459937.952 24 Dec 2022 09:57 24 Dec 2022 10:50 24 Dec 2022 11:44
2459940.420 26 Dec 2022 21:11 26 Dec 2022 22:04 26 Dec 2022 22:58
2459942.888 29 Dec 2022 08:25 29 Dec 2022 09:18 29 Dec 2022 10:12
2459945.356 31 Dec 2022 19:39 31 Dec 2022 20:32 31 Dec 2022 21:25
2459947.824 03 Jan 2023 06:53 03 Jan 2023 07:46 03 Jan 2023 08:39

(2092) Michael Heald — Dec. 11, 2022, 9:15 p.m.

The baseline is pretty uncertain, according to the data in AAVSO. I hope to be able to add some time series for the baseline once my system comes back from repair, though with my current horizon limitations after moving (trees!), I won't have stretches of extended visibility on any one evening. Would AAVSONet be able to perform a time series around the eclipse and then a more relaxed time series like I suggested over a number of days in order to see if anything else is going on with the baseline? Best regards.

Mike

(4726) Kenneth Menzies — Dec. 13, 2022, 6:31 p.m.

Mike:
Assume this will be observed on MPO61. What eclipses will be visible at this location?

(4726) Kenneth Menzies — Dec. 13, 2022, 6:50 p.m.

Mike:

Committed to MPO61 on 4 nights that I think will have correct UTC? Is the 50 minutes duration long enough for the eclipse? To get TOM, could image less than full eclipse (1.8 hrs?).

(2092) Michael Heald — Dec. 13, 2022, 7:58 p.m.

I'm not sure. I don't know the light curve. I only found one graph of the curve, and the eclipse was V shaped. The curve showed 3 eclipses; however, none were well covered (in my opinion). Additionally, the baseline was very fuzzy/indistinct in that curve. I'm curious if the primary is variable as well. So, I would prefer a good time series of the entire eclipse and enough observations to look at the baseline. Thanks. Mike

(3000) Sebastián Otero — Dec. 13, 2022, 9:47 p.m.

You have a light curve in VSX cpmbining the discoverer's data and CRTS data.
https://www.aavso.org/vsx_docs/418010/1249/UCAC4_457-001970_LC.png

It would be interesting if you can plan observations for Min II, not only Min I (those happen at phase 0.50) because we don't know if the two eclipses are slightly different or not.

(2092) Michael Heald — March 28, 2023, 9:46 a.m.

Just following up. Is there an estimate of when the observation run might occur? Thanks. Mike

Comments on this proposal are closed.