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2 edition of Studies in classical cepheids in the near infrared. found in the catalog.

Studies in classical cepheids in the near infrared.

Douglas Lindsay Welch

Studies in classical cepheids in the near infrared.

by Douglas Lindsay Welch

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Published .
Written in


The Physical Object
Pagination87 leaves
Number of Pages87
ID Numbers
Open LibraryOL16343390M

"Large Magellanic Cloud Near-Infrared Synoptic Survey. II. The Wesenheit Relations and Their Application to the Distance Scale"; Bhardwaj et al., AJ, , 88 () Link to article here. M33 Synoptic Stellar Survey. I was the PI of an NSF-funded project to study the Cepheids and Miras in M33 both at optical and near infrared wavelengths. The regularly pulsating atmospheres of classical Cepheids provide a unique laboratory to study the formation of the helium spectrum in cool stars. We present high resolution high S/N spectroscopy of seven Cepheids at μm with the FTS at the Canada-France-Hawaii telescope.

  Assuming that the four Cepheids in the NSD are located at the distance of the Galactic Centre and that the near-infrared extinction law, i.e. wavelength dependency of the interstellar extinction, is not systematically different between the NSD and other bulge lines of sight, most of the other Cepheids presented here are located significantly Cited by: Mean angular diameters, distances, and pulsation modes of the classical Cepheids FF Aquilae and T Vulpeculae. CHARA/FLUOR near-infrared interferometric observations A. Gallenne, et al., Astronomy and Astrophysics, , 87 (). The relationship between γ Cassiopeiae’s X-ray emission and its circumstellar environment.

We present new thermal IR photometry and spectral energy distributions (SEDs) of eight classical Cepheids (type I) and three type II Cepheids, using VISIR. Abstract. We present the results of long-baseline interferometric observations of the classical Cepheids Polaris and δ Cep in the near infrared K ′ band (− µm), using the FLUOR instrument of .


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Studies in classical cepheids in the near infrared by Douglas Lindsay Welch Download PDF EPUB FB2

The discovery of K-excesses in three Type II Cepheids is also reported. The distance to M31 (NGC ) has been determined using H photometry of seven classical Cepheids in Fields III and IV. Identification of contaminated photometry is described.

Uncontaminated observations have been reduced to intensity-weighted mean magnitudes. The spectroscopy and near-infrared images allowed the team to more definitely determine the “classical” status of five Cepheids.

These five Cepheids again lie in the outer reaches of the Milky Way’s disk, though at distances less extreme than those found in Chakrabarti’s study, betw light-years from the galaxy’s center. observations of Cepheids in the visible to near-infrared region, where the effects of interstellar extinction are reduced.

The extension of photometric imaging to increasingly fainter brightness. Near-infrared observations of Cepheids have several advan-tages over the optical; however, to date, NIR observations of Galactic Cepheids are limited mostly to the studies performed by Welch et al.

(), Laney & Stobie (), and Barnes et al. (), hereafter collectively referred to as WLB. When. We present measurements of 68 classical Cepheids, most detected from the Canada-France-Hawaii Telescope POMME Survey, with periods from 10 to 78 days observed in the near-infrared by the Panchromatic Hubble Andromeda Treasury Program using the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST).

The study utilizes photometric data for more than common classical Cepheids (Fundamental (FU) and First overtone (FO)) in optical (V, I), near-infrared (Y, J, K>s) and mid-infrared ([] and [] μm) photometric : Sukanta Deb, Kerdaris Kurbah, Harinder P Singh, Shashi M Kanbur, Chow-Choong Ngeow, Biman J Medhi, S.

Moreover, the extent to which our Galaxy’s stellar and gas disk morphologies are mutually consistent is also unclear. Classical Cepheids, primary distance indicators with distance accuracies of 3–5% (ref.), offer a unique opportunity to develop an intuitive and accurate three-dimensional by: As distance and extinction are usually degenerate, it is important to develop suit- able methods to robustly anchor the distance scale.

Here, we introduce a near- infrared (near-IR) optimal distance method to determine both the extinction values of and distances to a large sample of Galactic classical Cepheids.

Classical Cepheids, what else. using near-infrared (NIR) and optical–NIR perio d–W esenheit recen t sp ectroscopic and photometric studies indicate that metal-p oor Cepheids are, at. We conducted near-infrared polarimetric observations of 52 classical Cepheids and the stars around them in and with the SIRPOL instrument.

The 52 classical Cepheids are identified by D´ek´any et al. (a, b) and Matsunaga et al. Among them, Watt, V.E./ Photometric study of R. Coronae Borealis variable stars, Welch, Douglas L./ JHK observations of classical cepheids and an improved calibration of the infrared period-luminosity relation, Welch, Douglas Lindsay/ Studies of classical cepheids in the near infrared, Wiegert, Paul.

A./. Abstract. Studies of the beat Cepheids in the beginning of the ’s accentuated the mass discrepancy problems of the classical Cepheids.

Earlier studies of the secondary bumps defining the Hertzsprung progression in Cepheid light curves and of Cepheids in open clusters with known distances gave two types of pulsation masses about 40% smaller than the estimated evolution by: 1.

Several remote classical Cepheids were discovered in by the Hubble Space Telescope in the galaxy denoted M (M is a member of the Virgo cluster, a rich cluster of galaxies.) Figure shows the period-luminosity relation for these Cepheids.

Use the two Cepheids nearest the figure′s best-fit line to estimate the distance to M   The slopes of the infrared relations agree with those found previously for type II Cepheids in globular clusters within the uncertainties.

Using the pulsation parallaxes of V Cen and SW Tau, the data lead to an LMC modulus uncorrected for any metallicity effects of ± by: Search the world's most comprehensive index of full-text books. My library. The data were taken with the Infrared Survey Facility (IRSF) m telescope and the SIRIUS near-infrared camera located at the South African Astronomical Observatory.

North is. Cepheid variable stars pulsate, which allows their distances to be determined from the periodic variations in brightness. Skowron et al. constructed a catalog of thousands of Cepheids covering a large fraction of the Milky Way.

They combined optical and infrared data to determine the stars' pulsation periods and mapped the distribution of Cepheids and the associated young stellar Cited by: Several classical Cepheids have variations that can be recorded with night-by-night, trained naked eye observation, including the prototype Delta Cephei in the far north, Zeta Geminorum and Eta Aquilae ideal for observation around the tropics (near the ecliptic and thus zodiac) and in the far south Beta Doradus.

CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): We present the results of long-baseline interferometric observations of the classical Cepheids Polaris and δ Cep in the near infrared K ′ band (− µm), using the FLUOR instrument of the CHARA Array.

Following our previous detection of a circumstellar envelope (CSE) around Car (Kervella et al. ), we. Characterizing Cepheids. Measuring the mean magnitude or period of a Cepheid, however, can be a pretty demanding task in its own right.

A Cepheid’s light curve looks different in different wavelengths (as shown in Figure 1, taken from Madore and Freedman ).The shorter-wavelength bands like the B and V-bands have light curves with larger amplitudes of variation and.

We present the largest near-infrared (NIR) data sets, JHKs, ever collected for classical Cepheids in the Magellanic Clouds (MCs). We selected fundamental (FU) and first overtone (FO) pulsators, and found ( FU, FO) Cepheids for Small Magellanic Cloud (SMC) and ( FU, FO) for Large Magellanic Cloud (LMC).Cited by: 9.By using the Spitzer Space Telescope InfraRed Array Camera (IRAC) and the Multiband Imaging Photometer (MIPS) we have detected an infrared excess around a sample of 7 nearby Cepheids [4].

This excess is the first direct evidence that Cepheid stars have warm (K) circumstellar dust, that may be associated to stellar mass loss.Finally, the differences between our interpretation of infrared photometry of Magellanic Cloud Cepheids and that of Mathewson, Ford, and Visvanathan () are discussed.

We show that the extreme distances derived in the latter study are probably the result of an inconsistent correction to mean magnitude, the assumption of zero intrinsic width.