The Mercury‐Manganese Binary Star<i>φ</i>Herculis: Detection and Properties of the Secondary and Revision of the Elemental Abundances of the Primary

Zavala, R. T.; Adelman, Saul J.; Hummel, C. A.; Gulliver, A. F.; Caliskan, H.; Armstrong, J. T.; Hutter, D. J.; Johnston, K. J.; Pauls, T.

doi:10.1086/510108

Cited by 23 publications

(52 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This linelist includes the Fuhr & Wiese (2006) log g f data for several Fe I and Fe II lines, usually referred to as FW06. The line data and log g f values were updated according to Adelman et al (2006) and Zavala et al (2007), in agreement with our previous abundance works (e.g. Saffe et al 2011).…”

Section: Observational Materialsmentioning

confidence: 87%

“…We caution that the error of the abundances σ presented in these tables correspond to the dispersion 4 http://kurucz.harvard.edu/programs.html of the abundances derived from different lines and do not include the error in the abundances of the Sun, in order to properly compare with previous abundance works (e.g. Zavala et al 2007;Saffe et al 2011). No uncertainty is quoted when only one line is present.…”

Section: Abundance Analysesmentioning

confidence: 98%

See 1 more Smart Citation

On the nature of sn stars

Saffe

Levato

2014

A&A

View full text Add to dashboard Cite

The sn stars were first discoved by Abt & Levato when studying the spectral types in different open clusters. These stars present sharp Balmer lines, sharp metallic lines (C II, Si II, Ca II, Ti II, Fe II), and broad coreless He I lines. Some of the sn stars seem to be related to CP stars. Initially Abt & Levato proposed a shell-like nature to explain the sn stars, although this scenario was subsequently questioned. There is no general agreement about their origin. We aim to derive abundances for a sample of 9 stars, including sn and non-sn stars, to determine the possible relation between sn and CP stars and compare their chemical abundances. That most sn stars belong to open clusters allows us to search for a possible relation with fundamental parameters, including the age and rotation. We also study the possible contribution of different effects to the broad He I lines observed in these stars, such as Stark broadening and the possible He-stratification. Effective temperature and gravity were estimated by Strömgren photometry and then refined by requiring ionization and excitation equilibrium of Fe lines. We derived the abundances by fitting the observed spectra with synthetic spectra using an iterative procedure with the SYNTHE and ATLAS9 codes. We derived metallic abundances of 23 different chemical elements for 9 stars and obtained low projected rotational velocities for the sn stars in our sample (v sin i up to 69 km s −1 ). We also compared 5 stars that belong to the same cluster (NGC 6475) and show that the sn characteristics appear in the 3 stars with the lower rotational velocity. However, the apparent preference of sn stars for objects with the lower v sin i values should be taken with caution due to the small number of objects studied here. We analysed the photospheric chemical composition of sn stars and show that approximately ∼40% of them display chemical peculiarities (such as He-weak and HgMn stars) within a range of temperature of 10 300 K−14 500 K. However, there are also sn stars with solar or nearly-solar (i.e. non-CP) chemical composition. We have studied the possible contribution of different processes to the broad He I lines present in the sn stars. Although NLTE effects could not be completely ruled out, it seems that NLTE is not directly related to the broad He I profiles observed in the sn stars. The broad-line He I 4026 Å is the clearest example of the sn characteristics in our sample. We succesfully fit this line in 4 out of 7 sn stars by using the appropriate Stark broadening tables, while small differences appear in the other 3 stars. Studying the plots of abundance vs. depth for the He I lines resulted in some sn stars probably being stratified in He. However, a further study of variability in the He I lines would help for determining whether a possible non-uniform He superficial distribution could also play a role in these sn stars. We conclude that the broad He I lines that characterize the sn class could be modelled (at least in some of these stars) by the usual radiati...

show abstract

Section: Observational Materialsmentioning

confidence: 87%

Section: Abundance Analysesmentioning

confidence: 98%

On the nature of sn stars

Saffe

Levato

2014

A&A

View full text Add to dashboard Cite

show abstract

“…These anomalies are thought to be produced by radiatively driven diffusion and gravitational settling (Michaud 1970). The observations of Zavala et al (2007) spatially resolve the companion of Her for the first time. The object had previously been known as a single-lined spectroscopic binary with a period of about 560 days (Babcock 1971;Aikman 1976) and an eccentric orbit.…”

Section: Introductionmentioning

confidence: 85%

“…In a recent paper Zavala et al (2007) reported interferometric observations of the mercury-manganese star Her [HD 145389, HR 6023, HIP 79101, J2000:0 ¼ 16 h 08 m 46:18 s , J2000:0 ¼ þ44 56 0 05:7 00 , spectral type B9:p(HgMn), V ¼ 4:22], which is a binary star. This object belongs to a class of peculiar nonmagnetic B-type stars that show abundance anomalies of several elements, some of which (such as Hg and Mn) can be enhanced by orders of magnitude (Preston 1974).…”

Section: Introductionmentioning

confidence: 99%

“…The object had previously been known as a single-lined spectroscopic binary with a period of about 560 days (Babcock 1971;Aikman 1976) and an eccentric orbit. Their interferometric measurements with the Navy Prototype Optical Interferometer (NPOI) allowed Zavala et al (2007) to measure the brightness of the companion and use this to estimate its spectral type. This, in turn, facilitated their detection of spectral lines of the secondary for the first time in spectra taken at the Dominion Astrophysical Observatory.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Astrometric-Spectroscopic Determination of the Absolute Masses of the HgMn Binary Star φ Herculis

Torres

2007

Astron J

View full text Add to dashboard Cite

The mercury-manganese star Her is a well-known spectroscopic binary that has been the subject of a recent study by Zavala and coworkers in which they resolved the companion using long-baseline interferometry. The total mass of the binary is now fairly well established, but the combination of spectroscopy with astrometry has not resulted in individual masses consistent with the spectral types of the components. The motion of the center of light of Her was clearly detected by the Hipparcos satellite. Here we make use of the Hipparcos intermediate data (''abscissa residuals'') and show that by combining them in an optimal fashion with the interferometry the individual masses can be obtained reliably using only astrometry. We reexamine and then incorporate existing radial velocity measurements into the orbital solution, obtaining improved masses of 3:05 AE 0:24 and 1:614 AE 0:066 M that are consistent with the theoretical mass-luminosity relation from recent stellar evolution models. These mass determinations provide important information for the understanding of the nature of this peculiar class of stars.

show abstract

Elemental abundance analyses with Coudé Echelle spectrograms from the TÜBİTAK National Observatory of Turkey: I. The HgMn stars 11 Per, HR 2801, and ν Cnc

Adelman

Yüce

2010

Astron Nachr

View full text Add to dashboard Cite

Using coadded spectrograms taken with the Coudé Echelle Spectrograph (CES) of the 1.50-m Russian-Turkish Telescope of the TÜBİTAK National Observatory (TUG) near Antalya in Turkey, elemental abundance analyses of three HgMn stars 11 Per, HR 2801, and ν Cnc were performed. Comparisons are made with spectra obtained with the long camera of the Dominion Astrophysical Observatory (DAO) coudé spectrograph and its SITe4 CCD. The CES equivalent widths are about 12% larger than that for the DAO long camera. Our first results from TUG data/spectra show that all three stars exhibit the Hg II λ3984 line and somewhat diverse abundance patterns. 11 Per tends to have underabundant light elements with underabundant and overabundant Fe-peak elements. HR 2801 has mostly underabundant elements, with a few elements having solar abundances while N and Mn are overabundant. The coolest star ν Cnc has light elements having mostly solar abundances, overabundant iron group abundances, and very overabundant SrYZr and Ba. Comparisons with the abundance patterns of other HgMn stars show that they have a wide diversity of abundance patterns.

show abstract

The Mercury‐Manganese Binary StarφHerculis: Detection and Properties of the Secondary and Revision of the Elemental Abundances of the Primary

Cited by 23 publications

References 47 publications

On the nature of sn stars

On the nature of sn stars

Astrometric-Spectroscopic Determination of the Absolute Masses of the HgMn Binary Star φ Herculis

Elemental abundance analyses with Coudé Echelle spectrograms from the TÜBİTAK National Observatory of Turkey: I. The HgMn stars 11 Per, HR 2801, and ν Cnc

Contact Info

Product

Resources

About