Proposal #557

Proposer	(50010) Augusto Damineli (augusto.damineli@gmail.com) obscode: DAUA
Assigned To	(3663) Dirk Terrell
Date Submitted	Sept. 11, 2024
Status	Allocated
Priority	Normal
Proposal	Project: The 2025.7 periastron passage of eta Carine Author: Augusto Damineli, IAGUSP/Brazil This star is a prototype of LBV stars and is an eccentric binary (p=2023d e=0.9) with wind-wind collision. It has been brightening in the last 4 orbital cycles, revealing an increasingly prominent peak in photometry and line intensity. This seems to be due to the decreasing extinction of an occulter intervening in our line-of-sight (Damineli et al. 2024, Gull et al. 2023). The exact behavior of the light-curve is not presently known, especially the evolution of the U-V color index. The dissipating occulter covers the so-called bore-hole (Madura & Owocki 2012) which is expected to be a very hot spot revealing the sub-photosphere of the primary star. In the long-term, the bore hole should change to bluer the color index, especially the U-V, which measures the Balmer jump. Observational strategy Our goal is to monitor the UBV magnitude of eta Car through the year 2025 at a cadence of: -1 visit per week in 01/January to 30/June -1 visit per day in 01/July to 30/September -1 visit per week in 1/October to 31/December Since the comparison in the field (HD303308) is ~4 magnitudes weaker, we need 100 images per filter per visit to be coadded to do not degrade the signal-to-noise of the target. The comparison star is at 1 arcmin North of the target. Exposure time texp=0.05 sec in Every filter (to be adjusted after the first visit) Target magnitudes : V=4.0; B=4.6; U=4.0 RA= 10h 45m 03.6s DEC= -59° 41′ 04.3″

Targets
Target	RA (H.HH)	Dec (D.DD)	Magnitude	Telescope	Observation Frequency	Expiration Date	Proprietary Term
eta Car	10.751000	-59.68453	4.0–4.6	BSM_S	5	Dec. 30, 2025	No

Comments

(4726) Kenneth Menzies — Sept. 30, 2024, 7:37 p.m.

committed to BSM_S

(50010) Augusto Damineli — Nov. 13, 2024, 12:59 a.m.

I don't know how the AAVSONET system works...I'm leaning som comments, waiting for help.
1- some setups were chosen because IO had the OC61 telescope in mind. Then I ask for some changes:
a) filters should be SU,B,V. (instead of UBV)
b) the exposure times should be at least 10X per filter, instead of 0.05 seconds.
c) the cadence of observations in the proposal is still valid

Q1- How can I get a testing run for the expositions?
Q2- When this can be done?

(50010) Augusto Damineli — Nov. 23, 2024, 6:43 p.m.

I just sent an email to mentor@aavso.org looking for someone who could help me to shape and start monitoring eta Carinae in 2025. Are just basic things on the robotic procedures.

(4726) Kenneth Menzies — Nov. 24, 2024, 4:24 p.m.

a. The filters have been SU,B,V since initially committed to BSM_S. A U filter is not available anyway.
b. I increased the exposures to 1 sec to account for smaller scope as requested.
c. The cadence has been every 5 days since committed. The weather and a new camera change have delayed when images are taken. I gather you have not seen any yet?

Q1. As soon as weather/hardware cooperate, you should get some images to test.
Q2. Same as Q 1 answer above. The proposal is already in the queue.

Ken

(50010) Augusto Damineli — Nov. 24, 2024, 6:13 p.m.

Hi Ken
The ultraviolet filter is VERY important.
Could I ask to change for a telescope that has U or SU filter??
BSM_berry?
or OC61+ defocusing?

(50010) Augusto Damineli — Nov. 24, 2024, 6:26 p.m.

Also
Where can I see the exposure times adopted for the first run?
My hair guess is that they should be in the probation
V=2 B=4 U=40s but U must see a sequence of images with different exposure times to fine-tune the optimal exposures.

(50010) Augusto Damineli — Nov. 25, 2024, 12:26 a.m.

Sorry
I just saw that there will be a SU Filter.
Forget my suggestion for a telescope change
But I'll need at least 3 images per filter to find the optimal exposure:

V=1 B=2 U=20s
V=2 B=4 U=40s
V=4 B=8 U=60s

(50010) Augusto Damineli — Dec. 13, 2024, 6:42 p.m.

I NEED HELP!
I need to get access to the setup of the images that will be taken for my target. Where can I find a link to setup the exposure time for each filtrer (SU,B,V) and define the number of images to be taken?
Or do I need to talk to someone?

(4726) Kenneth Menzies — Dec. 15, 2024, 3:38 a.m.

we talked by email to resolve questions.

(50010) Augusto Damineli — Dec. 16, 2024, 8:52 p.m.

I have been helped (a lot) by Ken.

Comments on this proposal are closed.