Preliminary Analysis of V and Hp Light Curves of 26 Carbon Miras

Mikulášek, Zdeněk; Gráf, Tomáš

doi:10.1007/s10509-005-4424-0

Cited by 4 publications

(5 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 6 shows a portion of our Echelle spectrum of StHα 55 centered on Hα, and for comparison the equivalent portion of a spectrum of the non-variable carbon star HD 183556 obtained with the Asiago Echelle spectrograph and the same instrumental set-up as adopted for StHα 55. The Hα emission component of StHα 55 is sharp and very similar to those typically observed in carbon Miras, as nicely seen in comparison with the high resolution Hα spectral atlas of Mikulasek and Graf (2005). On the contrary, the Hα emission lines of symbiotic stars are far wider and present multicomponents and frequent central reversals (e.g.…”

Section: Profile and Variability Of Hα Emissionsupporting

confidence: 76%

StHa 55: a carbon Mira, not a symbiotic binary

Munari,

Siviero,

Graziani

et al. 2009

Preprint

View full text Add to dashboard Cite

We carried out a V R C I C photometric monitoring of StHα 55, and in addition we obtained low resolution absolute spectro-photometry and high resolution Echelle spectroscopy. Our data show that StHα 55 is a carbon Mira, pulsating with a 395 day period, with =13.1 mean brightness and ∆V =2.8 mag amplitude. It suffers from a low reddening (E B−V =0.15), lies at a distance of 5 kpc from the Sun and 1 kpc from the galactic plane, and its heliocentric systemic velocity is close to +22 km sec −1 . The difference between the radial velocity of the optical absorption spectrum and that of the Hα emission is unusually small for a carbon Mira. The spectrum of StHα 55 can be classified as C-N5 C 2 6 − . Its 13 C/ 12 C isotopic ratio is normal, and lines of BaII and other s-type elements, as well as LiI, have the same intensity as in field carbon stars of similar spectral type. The Balmer emission lines are very sharp and unlike those seen in symbiotic binaries. Their intensity changes in phase with the pulsation cycles in the same way as seen in field carbon Miras. We therefore conclude that StHα 55 is a bona fide, normal carbon Mira showing no feature supporting a symbiotic binary classification, as previously hypothesized.

show abstract

Section: Profile and Variability Of Hα Emissionsupporting

confidence: 76%

StHa 55: a carbon Mira, not a symbiotic binary

Munari,

Siviero,

Graziani

et al. 2009

Preprint

View full text Add to dashboard Cite

show abstract

“…Another possibility is that these are not two distinct peaks of Balmer line emission but represent a single extended episode of emission that is dimmed in the middle by dust obscuration or some other process. The time dependence of the Hα emission in the spectra of a number of carbon stars has been documented by Mikulášek & Gráf (2005) but they observed RS Cyg only twice, both times near maximum light. The three C 2 bands all show a pronounced increase in strength in the latter part of the cycle while the variation in the CN bands is more symmetric about maximum light.…”

Section: Spectroscopy Resultsmentioning

confidence: 96%

The Long-term Spectroscopic and Photometric Behavior of the Carbon Star RS Cygni

Cadmus

2022

View full text Add to dashboard Cite

RS Cygni is a semiregular variable carbon star that has a distinctive light curve. Twenty-one years of optical spectroscopic and photometric observations of this star made at Grinnell College have been used not only to produce a comprehensive survey of the behavior of this star but also to compare these two sets of data. A number of spectral features vary in strength with the cycle of the star and some, but not all, of this variation is correlated with the dips that often occur near the maxima of the light curve. In particular, the strengths of the Balmer emission lines often have two peaks per cycle. Such correlation might be consistent with a mechanism for producing the dips, such as dust formation, that reduces the brightness in a way that does not involve rapid changes in photospheric characteristics. The large amount of data and the precision of the photometry presented give an unusually detailed view of how the light of RS Cyg varies over time.

show abstract

“…Mira variables displays emission lines, mainly the higher lines in the Balmer series, peaking in intensity at maximum brightness for both O-and C-rich varieties (e.g. Panchuk 1978, Yamashita et al 1977, Mikulasek and Graf 2005, with large excursion in intensity along the pulsation cycle. When the first Echelle spectrum was exposed on June 10, IRC−10443 was on the rise and close to maximum brightness (pulsation phase 0.86), while for the July 22 spectrum it was declining and close to minimum brightness (pulsation phase 0.37).…”

Section: Spectral Classification and Radial Velocitymentioning

confidence: 99%

IRC-10443: a multi-periodic SRa variable and the nature of long secondary periods in AGB stars

Munari,

Siviero,

Ochner

et al. 2008

Preprint

View full text Add to dashboard Cite

We obtained BV I C photometry of IRC−10443 in 85 different nights distributed over two years, and in addition low resolution absolute spectro-photometry and high resolution Echelle spectroscopy. Our data show that IRC −10443, which was never studied before in any detail, is a SRa variable, characterized by ∆B=1.27, ∆V =1.14 and ∆I=0.70 mag amplitudes and mean values =13.75, =11.33 and =6.18 mag. Two strong periodicities are simultaneously present: a principal one of 85.5 (±0.2) days, and a secondary one of 620 (±15) days, both sinusoidal in shape, and with semi-amplitudes ∆V =0.41 and 0.20 mag, respectively. IRC−10443 turns out to be a M7III star, with a mean heliocentric radial velocity −28 km/s and reddened by E B−V =0.87, a third of which of circumstellar origin. The same 0.5 kpc distance is derived from application of the appropriate period-luminosity relations to both the principal and the secondary periods. The long secondary period causes a sinusoidal variation in color of 0.13 mag semi-amplitude in V − I C , with IRC−10443 being bluest at maximum and reddest at minimum, and with associated changes in effective temperature and radius of 85 K and 6%, respectively. This behavior of colors argues in favor of a pulsation nature for the still mysterious long secondary periods in AGB stars.

show abstract

Preliminary Analysis of V and Hp Light Curves of 26 Carbon Miras

Cited by 4 publications

References 2 publications

StHa 55: a carbon Mira, not a symbiotic binary

StHa 55: a carbon Mira, not a symbiotic binary

The Long-term Spectroscopic and Photometric Behavior of the Carbon Star RS Cygni

IRC-10443: a multi-periodic SRa variable and the nature of long secondary periods in AGB stars

Contact Info

Product

Resources

About