Proposal #94

Proposal for Analysis of Legacy Data for the SRB Variable FY Lib

Member Name and Observer Code: Edward Wiley/WEY

Summary of why the observations of each Target is important scientifically or educationally useful to the member.
Smith et al. (2002, Astronomical Journal, volume 123, 1411) have demonstrated that some Mira variables have a phase lag between Ic and V photometric maxima. Dutton et al (abst: http://www.nacaa.org.au/node/1007) report a similar result for the Mira R Carinae. This phenomenon has not been, to my knowledge, investigated in the SR-class of variables that show much less regularity in their periods. It may be of astrophysical interest if such lags are also present in irregular M5 variables.

User’s plan for the data, i.e. AAVSO data base, journal article, education or outreach.
This is a legacy proposal to process images already collected for the SRB variable FY Lib. If maxima in Ic lag behind maxima in V, then this would be worthy of publication. Note however that Smith et al. did not find this lag in all M-class variables they investigated. Processing these data will also permit me to access the feasibility of submitting a larger proposal to extend the project to SRA and other bright SRB variables. All results will be reported to the AAVSO data base.

Request images be sent to VPHOT (free to members): I would like the images to be placed in my VPhot account.

Check Variable Star Index (https://www.aavso.org/vsx/):

Target(s) name verification to ensure name is listed: FY Lib (000-BCW-244, 381 observations) is listed. It is a M5III SRB.
Target Sky Coordinates (J2000): RA: 14 57 46.55, Dec: -12 26 15.3 (224.44396 -12.43758)
Target V magnitude range: 6.5 - 7.78 V

Appropriate comparison stars with standard photometry. .
Unfortunately, the 120’ chart does not show comparison stars. (This may be a browser glitch.) I will request new comparison stars from the comp team if needed after I download images and check for comp stars in the FOV. There are at least two mag 7-8 stars near the variable that may be suitable (based on a search using Aladin and CDS VivieR catalogs.

Observation Parameters: This is a Legacy proposal, thus cadence, filters, number of images and other observational parameters are moot. Start and finish dates are determined by the Legacy data.