The star cluster in Coma Berenices

Trumpler, Robert J.

doi:10.5479/ads/bib/1938licob.18.167t

Cited by 51 publications

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“…The lower main sequence is unusually short because it terminates at about V ∼ 10.5, according to the classical UBV paper of Johnson & Knuckles (1955) who observed stars from Trumpler's (1938) list of members. This limit corresponds to the spectral type K0V.…”

Section: Introductionmentioning

confidence: 96%

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Membership, binarity, and rotation of red dwarfs in the nearby open cluster Coma Berenices (Melotte 111)

Mermilliod¹,

Grenon

Mayor

2008

A&A

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Context. Although several attempts have been made to identify solar-type members on the main sequence of the nearby open cluster Coma Berenices (Mel 111), the population of the lower main sequence is still poorly known. Aims. We observed 46 new candidates to search for new members and monitored known spectroscopic-binary members to determine orbital parameters. Methods. We obtained a total of 903 radial-velocity measurements of 69 solar-type stars in the field of Mel 111 with the CORAVEL spectrovelocimeter over 20 years. Results. Among the 35 stars from Trumpler's list, 23 are members according to their radial velocities and photometry. We were able to confirm the membership of only 8 stars among the 46 candidates observed. Six double-lined and ten single-lined spectroscopic binaries were discovered. Six only are members and an orbit was determined for them and for 4 double-lined non-members. The binary frequency is 22% (7/32). The cluster mean radial velocity is +0.01 ± 0.08 km s −1 based on 28 members. Conclusions. The lower main sequence of the Coma Berenices open cluster is still rather poorly populated. The cluster size may be much larger that usually accepted. Accordingly extensive programmes to determine precise proper motions, radial velocities and photometry should be undertaken to identify faint cluster members outside the cluster central area. If a significant population of faint members cannot be identified, Coma Ber could be a prominent example of dynamical evolution leading to star evaporation.

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Section: Introductionmentioning

confidence: 96%

“…However, no long term monitoring of this sample has been carried out so far and no orbital elements Article published by EDP Sciences have been published for the spectroscopic binaries discovered in Coma Berenices by Trumpler (1938) or Kraft (1965), with the exception of that for Tr 111 (Kraft 1965).…”

Section: Introductionmentioning

confidence: 99%

Membership, binarity, and rotation of red dwarfs in the nearby open cluster Coma Berenices (Melotte 111)

Mermilliod¹,

Grenon

Mayor

2008

A&A

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“…The first detailed survey of the Coma open cluster was carried out by Trumpler (1938), who identified 37 probable members with m p < 10.5 in a circular region of 7 • diameter centred on the cluster using proper motion, radial velocity, and spectrophotometric measurements. Several further studies (e.g.…”

Section: Introductionmentioning

confidence: 99%

The mass function of the Coma Berenices open cluster below 0.2 M_⊙: a search for low-mass stellar and substellar members

Melnikov

Eislöffel

2012

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Context. Little is known about the population of the Coma Berenices open cluster (age ∼500 Myr) below 0.2 M , and statistics show that there is a prominent deficit of very low-mass objects in this mass range compared to younger open clusters with ages of <250 Myr. Aims. We search for very low-mass stars and substellar objects (brown dwarfs) in the Coma open cluster to derive the present-day cluster mass function below 0.2 M .Methods. An imaging survey of the Coma open cluster in the R-and I-bands was carried out with the 2k × 2k CCD Schmidt camera at the 2-m telescope in Tautenburg. We performed a photometric selection of the cluster member candidates by combining results of our survey with 2MASS JHK s photometry. We also analysed low-resolution optical spectroscopic observations of a sample of 14 of our stellar cluster member candidates to estimate their spectral types and luminosity.Results. We present a photometric survey covering 22.5 deg 2 around the Coma open cluster centre with a completeness limit of 21. m 5 in the R-band and 20. m 5 in the I-band. Using optical/IR colour−magnitude diagrams, we identify 82 very low-mass cluster member candidates in the magnitude range 14. m 7 < I < 20. m 1. Five of them have luminosities and colour indices consistent with brown dwarfs. We calculate a mass spectrum of the very low-mass end of the cluster under the assumption that all selected candidates are probable cluster members. The calculated present-day mass function (dN/dm ≈ m −α ) can be divided into two parts with a slope of α = 0.6 in the mass interval 0.2 > M > 0.14 M and α ∼ 0 in 0.14 > M > 0.06 M . Conclusions. Our analysis of the spectroscopy of 14 objects shows that they are very low-mass MV-dwarfs of spectral type and luminosity consistent with Coma open cluster membership. This suggests that the membership probability of our other candidates may be high. Our results suggest that the mass function of the Coma open cluster can be traced towards substellar objects, but comparison with a mass spectra of younger clusters indicates that the Coma open cluster has probably lost its lowest mass members by means of dynamical evolution.

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“…The data are based on a compilation of 12 different catalogs. The first exhaustive study of the cluster was carried out by Trumpler (1938), determining definite cluster membership for the brighter stars. For some of the fainter stars the membership remained in doubt.…”

Section: Introductionmentioning

confidence: 99%

An astrometric catalogue for the area of Coma Berenices

Abad¹,

Vicente

1999

Astron. Astrophys. Suppl. Ser.

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The star cluster in Coma Berenices

Cited by 51 publications

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Membership, binarity, and rotation of red dwarfs in the nearby open cluster Coma Berenices (Melotte 111)

Membership, binarity, and rotation of red dwarfs in the nearby open cluster Coma Berenices (Melotte 111)

The mass function of the Coma Berenices open cluster below 0.2 M_⊙: a search for low-mass stellar and substellar members

An astrometric catalogue for the area of Coma Berenices

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The star cluster in Coma Berenices

Cited by 51 publications

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Membership, binarity, and rotation of red dwarfs in the nearby open cluster Coma Berenices (Melotte 111)

Membership, binarity, and rotation of red dwarfs in the nearby open cluster Coma Berenices (Melotte 111)

The mass function of the Coma Berenices open cluster below 0.2 M⊙: a search for low-mass stellar and substellar members

An astrometric catalogue for the area of Coma Berenices

Contact Info

Product

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The mass function of the Coma Berenices open cluster below 0.2 M_⊙: a search for low-mass stellar and substellar members