Paradise, Michigan

Olsen, William

doi:10.14321/j.ctt1qv5n1h.38

Cited by 43 publications

(85 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A circular diaphragm of 17 arcsec diameter was used. Details on the spectrometer and the (semi)automatic mode of the telescope are given by Olsen (1993). Table 2 lists the characteristics of the program stars and the comparison stars used in the photometry.…”

Section: Recent Observationsmentioning

confidence: 99%

The eclipsing double-lined binaries V883 Cen and Mus

Hensberge

Nitschelm

Olsen³

et al. 2007

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We derive the orbital period and monitor in detail the eclipses of two deep‐southern double‐lined eclipsing binaries of considerable interest. We present new uvby photometry over more than 100 nights for V883 Cen, scan for the first time the eclipses of η Mus and analyse the data for these two systems together with earlier published photometry. We also add information from high‐dispersion spectra. V883 Cen consists of two sharp‐lined, mid‐B‐type stars in an orbit of 35.44733 d. The slower rotating component, Prot= 55.215 d, is a chemically peculiar star of the type He‐weak SrTi that is partially eclipsed by its slightly more massive companion. Owing to the high eccentricity of the orbit and its orientation, only one eclipse occurs. The orbital period of η Mus is 57.5 h, rather than the 20 d quoted up to the present in the literature. That close binary, consisting of two late‐B‐type stars, shows identical partial eclipses. Interest in the close binary is triggered by the pre‐main‐sequence companion at 2.7 arcsec. HD 118978, one of the comparison stars used for V883 Cen, is identified as a new variable. This fast‐rotating B9 (sub)giant belongs presumably to the class of slowly pulsating B‐type stars.

show abstract

Section: Recent Observationsmentioning

confidence: 99%

The eclipsing double-lined binaries V883 Cen and Mus

Hensberge

Nitschelm

Olsen³

et al. 2007

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…IC 4651 has a metal abundance similar to the Hyades cluster, a coincidence which argues for a direct fit to the Hyades main sequence to determine IC 4651's distance. Strömgren photometry in the Hyades is available from studies by Crawford & Perry (1966) as well as from the catalog of Olsen (1993). As the Hyades cluster is near enough to neglect reddening, observed colors may be considered equivalent to reddening-free indices.…”

Section: Distance and Agementioning

confidence: 99%

CCD [ITAL][CLC]uvby[/CLC][/ITAL]Hβ Photometry in Clusters. I. The Open Cluster Standard, IC 4651

Anthony-Twarog¹,

Twarog²

2000

The Astronomical Journal

View full text Add to dashboard Cite

CCD photometry of the intermediate-age open cluster, IC 4651, on the uvbyHβ system is presented and analyzed. By using a combination of the information from the color-magnitude diagram (CMD) and the color-color diagrams, a sample of 98 highly probable main sequence cluster members with high photometric accuracy is isolated. From this sample, adopting the intrinsic color relation of Olsen (1988), E(b − y) = 0.062 ± 0.003 and [Fe/H] = +0.077 ± 0.012, where the errors quoted are the standard errors of the mean and refer to the internal errors alone. Use of the Nissen (1988) intrinsic color relation produces E(b − y) = 0.071 and [Fe/H] = +0.115. Adopting the lower reddening, a direct main-sequence fit to the Hyades with (m − M) = 3.33 leads to (m − M) = 10.15, while isochrones with convective overshoot and zeroed to the Hyades produce an age of 1.7 ± 0.1 Gyr, with an excellent match to the morphology of the turnoff. The higher reddening produces (m − M) = 10.3 and an age lower by 0.1 Gyr. Comparison with the CMD of NGC 3680 shows that the two clusters have virtually identical morphology which, in combination with their similar compositions, produces identical ages. Coincidentally, the shifts in the CMD necessary to superpose the two clusters require that the apparent moduli of IC 4651 and NGC 3680 be the same, while E(b − y) 4651 = E(b − y) 3680 + 0.04.

show abstract

“…Stars belonging to the red HB are c 0000 RAS clearly identified in this diagram as metal-poor stars with 0.28 < (b − y)0 < 0.46 and c0 ∼ −1.815(b − y)0 + 1.26. In order to enlarge the original sample of five stars with V < 9 in the list of Anthony-Twarog & Twarog, we considered all stars listed in the homogeneized catalogue of Strömgren photometry (Hauck & Mermilliod 1990) occupying a similar position in the c1, b − y diagram (we also considered the catalogues by Olsen 1993Olsen , 1994aOlsen , 1994b, but they did not provide additional good candidates). The selection criteria were V < 9, 0.2 < (b − y) < 0.5, 0.4 < c1 < 0.8, m1 < 0.15, and −0.1 < [c1 + 2 (b − y) − 1.2] < 0.2.…”

Section: The Red Horizontal Branch Starsmentioning

confidence: 99%

The absolute magnitude of field metal-poor horizontal branch stars

Gratton¹

1998

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

HIPPARCOS satellite parallaxes for 22 metal-poor field horizontal branch stars with Vo<9 are used to derive their absolute magnitude. The weighted mean value is Mv=+0.69+/-0.10 for an average metallicity of [Fe/H]=-1.41; a somewhat brighter average magnitude of Mv=+0.60+/-0.12 for an average metallicity of [Fe/H]=-1.51 is obtained eliminating HD17072, that might be on the first ascent of the giant branch rather than on the horizontal branch. The present values agree with determinations based on proper motions and application of the Baade-Wesselink method to field RR Lyraes; they are from 0.1 to 0.2 mag fainter than those based on calibration of cluster distances obtained by using local subdwarfs, and on alternative distance calibrators for the LMC. The possibility that there is a real difference between the luminosity of the horizontal branch for clusters and the field is briefly commented.Comment: 7 pages (Latex) submitted to Monthly Notices of the Royal Astronomical Societ

show abstract

Paradise, Michigan

Cited by 43 publications

References 0 publications

The eclipsing double-lined binaries V883 Cen and Mus

The eclipsing double-lined binaries V883 Cen and Mus

CCD [ITAL][CLC]uvby[/CLC][/ITAL]Hβ Photometry in Clusters. I. The Open Cluster Standard, IC 4651

The absolute magnitude of field metal-poor horizontal branch stars

Contact Info

Product

Resources

About