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Proposal #484

Proposer (44938) Sauro Gaudenzi (assodicuori2013@email.it) obscode: GSAD
Assigned To(3663) Dirk Terrell
Date SubmittedFeb. 15, 2024
StatusAllocated
PriorityNormal
Proposal

I'm Sauro Gaudenzi, my observer code is GSAD, following the AAVSO 851 alert and in support of the observations planned in the coming months with the Hubble Space Telescope I request the use of a telescope to observe the spectroscopic eclipsing binary red supergiant V695 Cyg in support of the observations planned in the coming months with the Hubble Space Telescope. This request for assistance was made to AAVSO by Dr. Philip Bennett (Dalhousie University). The HST will observe the evolution of the ultraviolet spectrum over 10 epochs at wavelengths < 3100 A during the partial, total, and near-eclipse phases of 31 Cyg until September 2024.

The goal of this program is to determine the amount of circumstellar absorption due to the red supergiant's wind throughout the eclipse period. These observations will map the density, velocity, ionization and temperature structure of the red supergiant and determine an accurate rate of mass loss for this important red supergiant. I ask that observations be made once or twice a week if possible until the end of May, so 60-second shots for each U-filter observation.

Targets
Target RA (H.HH) Dec (D.DD) Magnitude Telescope Observation Frequency Expiration Date Proprietary Term
V695 Cyg 20.227197 46.74133 3.0–4.0 BSM_NH2 4 May 30, 2024 No

Comments

(44938) Sauro Gaudenzi — Feb. 16, 2024, 12:11 a.m.

I would like to point out that 60 minutes of integration or exposure are sufficient for each observation

(3663) Dirk Terrell — Feb. 19, 2024, 8:31 p.m.

Approved for multi-filter observations, at least BVI but a UV band would also be useful.

(4848) George Silvis — Feb. 20, 2024, 12:13 a.m.

Submitted to BSM_NH2
U not available: chose SU
Exposures set short 2 and image count high, 10 because it is so bright
Advise if adjustments are needed.

(44938) Sauro Gaudenzi — Feb. 20, 2024, 10:26 a.m.

Ok that's perfectly fine

(44938) Sauro Gaudenzi — Feb. 23, 2024, 10:52 a.m.

Hello and have a good day, regarding the subject V 695 Cyg I received the data on Vphot, but I was only able to perform the photometry with the I B V filters and, in terms of exposure, it would be fine, if possible maybe an extra second otherwise it's fine as it is , however, as regards the SU filter I was unable to do anything as it is not possible to have the comparison stars, when I ask it this message appears "Comp stars/sequence exist, but none was imported due to no photometry for this particular filter, or too faint to be detected. " , now if it is possible to increase the exposure a little with this filter, otherwise I will try to perform a manual search for the calibration stars that the AAVSO gives, taking inspiration from other filters. Thank you very much for your cooperation and have a nice day

(4848) George Silvis — Feb. 23, 2024, 8:08 p.m.

The images of V695 Cyg appear to be saturated.
The system will automatically reduce the exposure, so keep monitoring before submitting data from these exposures.

It does look like SU comparison data is hard to find.
Best to ask for help from the the sequence team: https://www.aavso.org/request-comparison-stars-variable-star-charts

(44938) Sauro Gaudenzi — Feb. 23, 2024, 8:22 p.m.

Ok thank you very much

Comments on this proposal are closed.