AAVSO: American Association of Variable Star Observers

Proposal #73

Proposer (3053) Andrew Pearce (apearce6916@gmail.com) obscode: PEX
Assigned To(3663) Dirk Terrell
Date SubmittedJuly 28, 2017

ASAS J143751-6454.9 is an LPV which only has observations from ASAS (available between 2001 and 2009 only). There are no observations in the AAVSO AID or any of the other surveys (based on a check performed through VSX) and there is no literature available which contains other observations apart from ASAS data. It was first brought to the attention of the AAVSO by Sebastian Otero who remarked on the dual maximum nature of this LPV. This was reported in the July 2017 issue of the AAVSO Newsletter. Analysis of the ASAS data (2001–2009) clearly shows a pronounced dual maximum with the secondary minimum being unusually deep. A preliminary period for this star is 539 days, which is quite long for an LPV. LPV's which show prominent dual maxima features in their light curves are relatively rare. Generally the first maxima is fainter than the first (but not always). The average time between the first fainter maxima and the brighter second one is 220 days (ranging from 200 to 231 days in the ASAS data) and then there's a further average duration of 327 days (ranging from 310-351 days) between the brighter second maximum and the next fainter one.

I have shared my ASAS analysis of this star with John Percy who remarked that he light curve clearly does not repeat from cycle to cycle, and the phase curve with a single period has a lot of scatter. Therefore it's more likely that the star is pulsating in (at least) two periods. Stan Walker, Director VSS, believes that the light curve behaviour of this star appears almost unique. Dual maxima LPV's are a rare subset of MIras in general with only 2 known in the northern sky and less than 10 in the southern sky.

I propose to utilise MJUO to undertake BVri photometry of this LPV at a cadence of approximately 30 days over a 1,100 day period. This will cover approximately 2 full cycles for the star. The exact cadence is not important for an LPV such as this and therefore there is a lot of flexibility of when data can be acquired for this star to suit MJUO priorities. It is hoped that the MJUO can observe the star well beyond the faint cut off limit evident in the ASAS data.

I have publicised this star throughout the AAVSO and in particular have targeted some southern visual observers with large telescopes to potentially supplement the CCD photometry undertaken as part of this proposal. The intention would be to analyse the data after this 3 year period and prepare a paper for JAAVSO summarising the results.

I trust I have provided enough information on this proposal. Please let me know if any further information is required.

Andrew Pearce (PEX)

Target RA (H.HH) Dec (D.DD) Magnitude Telescope Observation Frequency Expiration Date Proprietary Term
ASAS J143751-6454.9 14.630858 -64.91525 17.0–12.5 OC61 Nov. 15, 2022 No


(3053) Andrew Pearce — July 29, 2017, 2:56 a.m.

If this proposal is accepted to use MJUO, I've worked out the optimum times to observe the target throughout the year (maximising altitude) as shown below. All times are in NZST and since the LPV is circumpolar, it can be observed all year round and on different dates than shown below (extrapolation can be used).

Jan 1 - 0200hrs
Feb 1 - 0300 hrs
Mar 1 - 0400 hrs
Apr 1 - 0200 hrs
May 1 - 0000 hrs
June 1 - 2200 hrs
July 1 - 2000 hrs
Aug 1 - 1930 hrs
Sept 1 - 2030 hrs
Oct 1 - 2100 hrs
Nov 1 - 2200 hrs or 0300 hrs
Dec 1 - 0200 hrs

(3053) Andrew Pearce — May 19, 2022, 9:10 a.m.

Observations of this target stopped in August last year. Is there any chance this can be extended by a few years? This is looking like being a rare Double Maximum Mira but we need to pick up a few more cycles to confirm.

(3663) Dirk Terrell — May 19, 2022, 1:39 p.m.

I don't think the TAC would have any problem with that.

(4726) Kenneth Menzies — May 19, 2022, 1:56 p.m.

Plan is still active. I increased the priority slightly. See if you get some images assuming it is not near sun now?

(3053) Andrew Pearce — May 19, 2022, 10:16 p.m.

Thanks Ken and Dirk. It's not near the Sun at the moment, it's actually the primary observing season at the moment.

Comments on this proposal are closed.