Stellar Pulsation and the Production of Dust and Molecules in Galactic Carbon Stars

Kraemer, K. E.; Sloan, G. C.; Keller, L. D.; McDonald, Iain; Zijlstra, A. A.; Groenewegen, M. A. T.

doi:10.3847/1538-4357/ab4f6b

Cited by 9 publications

(4 citation statements)

References 79 publications

(121 reference statements)

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“…High-amplitude pulsations cause mass-loss phenomena via the stellar wind (Perrin et al 2020), which leads to the enrichment of the interstellar medium with elements heavier than nickel produced by the slow neutron-capture process. Therefore, Miras, like other LPVs, are important tracers of galactic chemistry (Whitelock et al 1997;Battistini & Bensby 2016;Kraemer et al 2019;Yu et al 2021).…”

Section: Introductionmentioning

confidence: 99%

The OGLE Collection of Variable Stars: Nearly 66,000 Mira Stars in the Milky Way

Iwanek

Soszyński

Kozłowski

et al. 2022

ApJS

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We present a collection of 65,981 Mira-type variable stars found in the Optical Gravitational Lensing Experiment (OGLE) project database. Two-thirds of our sample (40,356 objects) are located in the Galactic bulge fields, whereas 25,625 stars are in the Galactic disk. The vast majority of the collection (47,532 objects) comprises new discoveries. We provide basic observational parameters of the Mira variables: equatorial coordinates, pulsation periods, I-band and V-band mean magnitudes, I-band brightness amplitudes, and identifications in other catalogs of variable stars. We also provide the I-band and V-band time-series photometry collected since 1997 during the OGLE-II, OGLE-III, and OGLE-IV phases. The classical selection process, i.e., being mostly based on the visual inspection of light curves by experienced astronomers, has led to the high purity of the catalog. As a result, this collection can be used as a training set for machine-learning classification algorithms. Using overlapping areas of adjacent OGLE fields, we estimate the completeness of the catalog to be about 96%. We compare and discuss the statistical features of Miras located in different regions of the Milky Way. We show examples of stars that change their type over time, from a semiregular variable to Mira and vice versa. This data set is perfectly suited to studying the three-dimensional structure of the Milky Way, and it may help to explain the puzzle of the X-shaped bulge.

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Section: Introductionmentioning

confidence: 99%

The OGLE Collection of Variable Stars: Nearly 66,000 Mira Stars in the Milky Way

Iwanek

Soszyński

Kozłowski

et al. 2022

ApJS

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“…Consequently, a better estimation of galactic distances is needed for a better understanding of the distribution of galactic carbon stars. Furthermore, differences in molecular gas features and dust emission of carbon stars between the MC and the MW have also recently been found by Kraemer et al (2019). This could play a role in making galactic carbon stars dimmer in the near-infrared.…”

Section: The Milky Waymentioning

confidence: 67%

Carbon stars as standard candles: I. The luminosity function of carbon stars in the Magellanic Clouds

Ripoche,

Heyl,

Parada

et al. 2020

Preprint

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Our goal in this paper is to derive a carbon-star luminosity function that will eventually be used to determine distances to galaxies at 50-60 Mpc and hence yield a value of the Hubble constant. Cool N-type carbon stars exhibit redder near-infrared colours than oxygen-rich stars. Using Two Micron All Sky Survey near-infrared photometry and the Gaia Data Release 2, we identify carbon stars in the Magellanic Clouds (MC) and the Milky Way (MW). Carbon stars in the MC appear as a distinct horizontal feature in the near-infrared ((J − K s ) 0 , M J ) colour-magnitude diagram. We build a colour selection (1.4 < (J − K s ) 0 < 2) and derive the luminosity function of the colourselected carbon stars. We find the median absolute magnitude and the dispersion, in the J band, for the Large Magellanic Cloud and the Small Magellanic Cloud to be, respectively, ( MJ = −6.284 ± 0.004, σ = 0.352 ± 0.005) and ( MJ = −6.160 ± 0.015, σ = 0.365 ± 0.014). The difference between the MC may be explained by the lower metallicity of the Small Magellanic Cloud, but in any case it provides limits on the type of galaxy whose distance can be determined with this technique. To account for metallicity effects, we developed a composite magnitude, named C, for which the errorweighted mean C magnitude of the MC are equal. Thanks to the next generation of telescopes (JWST, ELT, TMT ), carbon stars could be detected in MC-type galaxies at distances out to 50-60 Mpc. The final goal is to eventually try and improve the measurement of the Hubble constant while exploring the current tensions related to its value.

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“…Therefore, a S/N cutoff was implemented in the reduction process: the calculation described above was performed only if the spectrum of the science target has a mean signal-to-noise ratio of 10 across the passband. If the spectrum of the science target has a S/N less than 10, the (Kraemer et al 2019) and is known to have broad spectral features in this wavelength range. In all plots, the green line is the observed spectrum, the blue line is the best fit ATRAN model spectrum, the teal line is the smooth polynomial assumed for the intrinsic source spectrum, and the black line is the telluric corrected spectrum.…”

Section: Methodsmentioning

confidence: 99%

“…(upper left) Example of a fit to a G063 spectrum; (upper right) Example of a fit to a G227 spectrum; (lower left) Example of a fit to a G329 spectrum; (lower right) Example of a somewhat poorer fit to a G063 spectrum. This source (TU Gem) is a carbon star(Kraemer et al 2019) and is known to have broad spectral features in this wavelength range. In all plots, the green line is the observed spectrum, the blue line is the best fit ATRAN model spectrum, the teal line is the smooth polynomial assumed for the intrinsic source spectrum, and the black line is the telluric corrected spectrum.…”

mentioning

confidence: 99%

Probing the Atmospheric Precipitable Water Vapor with SOFIA, Part. IV. Water Vapor Estimates from FORCAST Grism Spectra

Vacca¹,

Iserlohe²,

Shenoy³

et al. 2023

PASP

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SOFIA was an airborne observatory for far-infrared astronomy stationed at the Armstrong Flight Research Center in Palmdale, CA, USA. Although SOFIA flew at altitudes of ∼41,000 ft, any far-infrared observations from within the Earth’s atmosphere are nevertheless hampered by water vapor absorbing the astronomical signal. The primary atmospheric parameter governing absorption at far-infrared wavelengths is the total upward precipitable water vapor (PWV). In this paper we present a method of deriving PWV values directly from low resolution (R ∼ 100–200) mid-infrared (5–40 μm) spectroscopic observations and apply it to low resolution grism spectra obtained with the FORCAST instrument on-board SOFIA. We then compare these values with those determined from the fifth European Re-analysis (ERA5) of the global atmospheric parameters provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) for the time and altitude corresponding to the SOFIA observations. In general, we find a very good correlation between the ERA5-ECMWF values and the values derived from the FORCAST grism spectra, especially for high signal-to-noise ratio data. These results indicate that ERA5-ECMWF PWV values can be used to generate the telluric corrections for FORCAST imaging data as well as grism spectra for which the PWV values cannot be determined directly. We also derive the resolving power of the various grism and slit width combinations for FORCAST. Our results will be useful for reprocessing the FORCAST data in the SOFIA archive.

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Stellar Pulsation and the Production of Dust and Molecules in Galactic Carbon Stars

Cited by 9 publications

References 79 publications

The OGLE Collection of Variable Stars: Nearly 66,000 Mira Stars in the Milky Way

The OGLE Collection of Variable Stars: Nearly 66,000 Mira Stars in the Milky Way

Carbon stars as standard candles: I. The luminosity function of carbon stars in the Magellanic Clouds

Probing the Atmospheric Precipitable Water Vapor with SOFIA, Part. IV. Water Vapor Estimates from FORCAST Grism Spectra

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