Spectroscopy of gamma Cas requested
Active Dates: Jan. 31, 2020 – Dec. 31, 2024
Abstract:
Ernst Pollmann (International Working Group ASPA (Active Spectroscopy in Astronomy)) has requested AAVSO observers' assistance in obtaining spectra of the very bright Be star gam Cas (HD 5394, 1.6-3V) in support of a long term study underway of HeI 6678 V/R periodicity in this star.
Justification:
Stee et al. (1998) proposed that the He excitation and ionization region, responsible for the emission in the HeI 6678 line, extends to 2.3 stellar radii. Thus, the HeI 6678 line has an important diagnostic value of activity close to the stellar surface. The time-dependent mass loss from the primary component of the gamma Cas binary system assumes that both photospheric and disk density variations lead to the double peak profile variations of HeI 6678. The analysis of the V/R periodicity (448 day) of the Hel 6678 double-peak emission for the period August 2009 to September 2019, cannot confirm the period, published [in] IBVS 6103 (2014), probably because of the few data available until 2014. The 448 day period found today, is based on a much longer monitoring time and a three times larger data set, from the data bases BAA, BeSS, and my own spectra.
Requested Data Types:
Spectroscopy
Targets
| Name | Magnitude | Variability Type | Photometry Notes | Spectroscopy Notes |
|---|---|---|---|---|
| gam Cas | 1.60 | GCAS+X+LERI: | Not Requested |
Cadence: Not Specified Resolution: 250 Desired SNR: 100 |
Spectroscopy Lines:
No spectroscopy lines provided
Photometry Filters:
No photometry filters provided
Comparison Stars:
No comparison stars provided
Co-Authorship
Observers are not eligible for co-authorship.
Additional Observer Input:
Not provided
Additional Submission Location:
Not provided
Forum URL
N/A
Notes:
Principal Investigator: Ernst Pollmann; Imported Campaign (Alert Notice #694)