Discovery of rapid spectral variability in the Ap star χ Psc

Aliev, S. G.; Исмаилов, Н. З.

doi:10.1134/1.1320499

Cited by 3 publications

(4 citation statements)

References 6 publications

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“…Thus, our observations revealed the two most probable frequencies n 2 and n 4 , which correspond to 1324 AE 80 mHz and 1440 AE 70 mHz respectively. These pulsation mode values are very close to the period values presented by Malanushenko et al (1998) as well as to those from spectral observations by Aliev and Ismailov (2000a) and Kanaan and Hatzes (1998). …”

supporting

confidence: 90%

“…The total spectrum range l ¼ 4300-6700 Å is covered with the matrix window in 40 orders. The observation procedure and spectral material have been described in the papers by Aliev and Ismailov (2000a;2001). Table I presents a log for individual programmed stars.…”

Section: Observations and Resultsmentioning

confidence: 99%

“…Nowadays, of the 4 known roAp stars, only four stars display a rapid variation in the oscillatory-type spectrum HR 1217 (Matthews et al, 1988), a Cir (Hatzes andKurster, 1994), g Equ (Kanaan and Hatzes, 1998;Aliev and lsmailov, 2001), w Psc (Aliev and Ismailov, 2000a). Observational features of this star group have been described in the reviews by Weiss (1986), Shibahashi (1987), Kurtz (1990), Matthews (1992) and Weiss et al (2000).…”

Section: Introductionmentioning

confidence: 97%

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RAPID DYNAMIC PROCESSES IN Ap STAR ATMOSPHERES

Исмаилов¹

2003

Astronomical & Astrophysical Transactions

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Long-term observations with short exposures in 1999-2001 allowed us to reveal the rapid variation in light velocities and equivalent widths of various spectral lines in the spectra of Ap stars w Psc and g Equ with pulsation periods 17 min and 12 min respectively. To determine the pulsation periods more precisely, a frequency analysis has been applied. Our observations show that, apart from the variability related to an axial rotation of the star, two more types of variability in an observable group of stars have been detected: firstly, short-term oscillations with 12-17 min periods; secondly, a relatively slow variability with 1.5-2.5 h characteristic times. The short-term spectrum variability is shown to be observed for all programmed stars, but only w Psc and g Equ spectra variations are periodic. The second, a slower type of spectrum variability (1.5-3 h), is also reliably observed for w Psc and g Equ stars. According to the observed spectral characteristics, the star y Aur may be referred to a subgroup of roAp stars.

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supporting

confidence: 90%

Section: Observations and Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

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RAPID DYNAMIC PROCESSES IN Ap STAR ATMOSPHERES

Исмаилов¹

2003

Astronomical & Astrophysical Transactions

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“…A large number of high-quality spectrograms with a dispersion of 4/mm were obtained . [1] Over the course of three nights, about 50 CCD spectrograms of the star θAur were obtained using an echelle spectrometer installed in the focus of the Coude 2m telescope SHAO NAS of Azerbaijan with the use of CCD matrix with 530x580 elements [2].…”

Section: Observations and Processingmentioning

confidence: 99%

Complex studies of magnetic cp stars III.analysis of variability and evolutionary status magnetic СР - stars θ Aur

Aliyev,

Khalilov,

Alishova

2023

A.Journ.Az.

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Based on complex observations, the characters of the photometric, magnetic and spectral variability, with a period of P = 3 d .6188, of the magnetic CP of the star θ Aur = HD 40312 were studied. The phase curves of the magnetic field (B e ), brightness (V ) and equivalent widths (Wλ) of the lines of peculiar elements (Si, Cr, Sr, etc.) are constructed, by means of which the phases corresponding to the maximal peculiar (P) and normal region (N) on the surface of the star are determined. It is revealed that all phase dependences are synchronous; that is, the extrema of the values of Be, V, and Wλ coincide within the error (φ = ±0.05). Hydrogen line profiles (Hγ, Hδ) were used to determine the fundamental parameters (T e and log g) for the normal (T e = 8800 K, log g = 3.65) and peculiar (T e = 9800 K, log g = 3.90) regions on the stellar surface. The effective temperature was also determined from the photometric indices (T e = 10100 K and 9500 K ). The location of the star θ Aur on the Hertzsprung-Russell diagram has been established, and thus its evolutionary status has been determined. It was found that the star HD 40312 is located closer to the upper boundary (TAMS) of the MS band.

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On the behavior of the Cii 4267.261, 6578.052 and 6582.882 Å lines in chemically peculiar and standard stars☆

Catanzaro

Leone

2002

New Astronomy

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Discovery of rapid spectral variability in the Ap star χ Psc

Cited by 3 publications

References 6 publications

RAPID DYNAMIC PROCESSES IN Ap STAR ATMOSPHERES

RAPID DYNAMIC PROCESSES IN Ap STAR ATMOSPHERES

Complex studies of magnetic cp stars III.analysis of variability and evolutionary status magnetic СР - stars θ Aur

On the behavior of the Cii 4267.261, 6578.052 and 6582.882 Å lines in chemically peculiar and standard stars☆

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