AAVSO: American Association of Variable Star Observers

Proposal #310

Proposer (45204) Krzysztof Zieliński (krzysztof.s.zielinski@gmail.com) obscode: ZKRA
Assigned To(3663) Dirk Terrell
Date SubmittedDec. 31, 2022

RT Cru

Magnitude range (according to VSX):
>11.1 - 13.3 V

Requested filters:
B, V, R, I

Exposition times:
The best possible in telescope owner's opinion. I request two (2x) images per filter to be made during every run (and uploaded to my VPhot account).

Observation cadence:
Daily (if time is available).

Observations start date:
As soon as possible.

Expiration date (YYYY-MM-DD format):
2023-06-01 (Of course, I am open to any changes if such are necessary.)

RT Cru is a ZAND type variable star with orbital period of 325 days and pulsation period of 63 days. According to Enhanced LCG, last observation of RT Cru was made on 2022-08-31. In total, there are 33590 observations of this star in AAVSO database (29123 in V-band and 2893 in B-band). RT Cru's case was included and described in scientific publications. Here are few examples:

- "The Nature of the Hard X-Ray-Emitting Symbiotic Star RT Cru" - G. J. M. Luna ; J. L. Sokoloski,

- "Light curves of symbiotic stars in massive photomeric surveys II: S and D’-type systems" - M. Gromadzki ; J. Mikołajewska ; I. Soszyński,

- "Observations of suspected symbiotic stars" - D. Cieslinski ; F. Elizalde ; J. E. Steiner.

There have been 4 notices for RT Cru in the AAVSO Alert Notice over several years:
- Special Notice #411: RT Cru observations need to be continued,
- Special Notice #409: Chandra observations scheduled for RT Cru,
- Alert Notice 503: Request for regular monitoring of the symbiotic variable RT Cru,
- Alert Notice 451: Monitoring of the Symbiotic Variable RT Cru Requested.

Therefore, I would like to provide continuity of photometric measurements. BSM-Berry (Bolt) is probably the best suited site for this proposal.
However, because R filter is not available there I would request only BVI images to be made if the proposal is accepted and allocated to BSM-Berry.

The star is said to be flickering in a 10-30 min. time scale.

All data would be submitted to AAVSO database after VPhot analysis.

Krzysztof Zieliński (ZKRA)

Target RA (H.HH) Dec (D.DD) Magnitude Telescope Observation Frequency Expiration Date Proprietary Term
RT Cru 12.581590 -64.56558 13.3–11.1 BSM_Berry 1 July 8, 2023 No


(4726) Kenneth Menzies — Jan. 10, 2023, 5:22 p.m.

Committed to Berry.

Comments on this proposal are closed.