Estimating the parameters of globular cluster M 30 (NGC 7099) from time-series photometry

N. Kains, D. M. Bramich, A. Arellano Ferro, R. Figuera Jaimes, U. G. Jørgensen, S. Giridhar, M. T. Penny, Khalid Al-Subai, J. M. Andersen, V. Bozza, P. Browne, M. Burgdorf, S. Calchi Novati, Y. Damerdji, C. Diehl, P. Dodds, M. Dominik, A. Elyiv, X. S. Fang, E. Giannini & 30 others S. H. Gu, S. Hardis, K. Harpsøe, T. C. Hinse, A. Hornstrup, M. Hundertmark, J. Jessen-Hansen, D. Juncher, E. Kerins, H. Kjeldsen, H. Korhonen, C. Liebig, M. N. Lund, M. Lundkvist, L. Mancini, R. Martin, M. Mathiasen, M. Rabus, S. Rahvar, D. Ricci, K. Sahu, G. Scarpetta, J. Skottfelt, C. Snodgrass, J. Southworth, J. Surdej, J. Tregloan-Reed, C. Vilela, O. Wertz, A. Williams

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Aims. We present the analysis of 26 nights of V and I time-series observations from 2011 and 2012 of the globular cluster M 30 (NGC 7099). We used our data to search for variable stars in this cluster and refine the periods of known variables; we then used our variable star light curves to derive values for the cluster's parameters. Methods. We used difference image analysis to reduce our data to obtain high-precision light curves of variable stars. We then estimated the cluster parameters by performing a Fourier decomposition of the light curves of RR Lyrae stars for which a good period estimate was possible. We also derived an estimate for the age of the cluster by fitting theoretical isochrones to our colour-magnitude diagram (CMD). Results. Out of 13 stars previously catalogued as variables, we find that only 4 are bona fide variables. We detect two new RR Lyrae variables, and confirm two additional RR Lyrae candidates from the literature. We also detect four other new variables, including an eclipsing blue straggler system, and an SX Phoenicis star. This amounts to a total number of confirmed variable stars in M 30 of 12. We perform Fourier decomposition of the light curves of the RR Lyrae stars to derive cluster parameters using empirical relations. We find a cluster metallicity [Fe/H]ZW =-2.01 ± 0.04, or [Fe/H]UVES =-2.11 ± 0.06, and a distance of 8.32 ± 0.20 kpc (using RR0 variables), 8.10 kpc (using one RR1 variable), and 8.35 ± 0.42 kpc (using our SX Phoenicis star detection in M 30). Fitting isochrones to the CMD, we estimate an age of 13.0 ± 1.0 Gyr for M 30.

Original languageEnglish
Article numberA36
JournalAstronomy and Astrophysics
Volume555
DOIs
Publication statusPublished - 5 Jul 2013

Fingerprint

globular clusters
photometry
estimating
time series
variable stars
light curve
stars
diagram
decomposition
color-magnitude diagram
image analysis
estimates
parameter
night
metallicity

Keywords

  • Globular clusters: individual: M 30 (NGC 7099)
  • Stars: variables: general
  • Stars: variables: RR Lyrae

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Kains, N., Bramich, D. M., Arellano Ferro, A., Figuera Jaimes, R., Jørgensen, U. G., Giridhar, S., ... Williams, A. (2013). Estimating the parameters of globular cluster M 30 (NGC 7099) from time-series photometry. Astronomy and Astrophysics, 555, [A36]. https://doi.org/10.1051/0004-6361/201321819

Estimating the parameters of globular cluster M 30 (NGC 7099) from time-series photometry. / Kains, N.; Bramich, D. M.; Arellano Ferro, A.; Figuera Jaimes, R.; Jørgensen, U. G.; Giridhar, S.; Penny, M. T.; Al-Subai, Khalid; Andersen, J. M.; Bozza, V.; Browne, P.; Burgdorf, M.; Calchi Novati, S.; Damerdji, Y.; Diehl, C.; Dodds, P.; Dominik, M.; Elyiv, A.; Fang, X. S.; Giannini, E.; Gu, S. H.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Hornstrup, A.; Hundertmark, M.; Jessen-Hansen, J.; Juncher, D.; Kerins, E.; Kjeldsen, H.; Korhonen, H.; Liebig, C.; Lund, M. N.; Lundkvist, M.; Mancini, L.; Martin, R.; Mathiasen, M.; Rabus, M.; Rahvar, S.; Ricci, D.; Sahu, K.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Vilela, C.; Wertz, O.; Williams, A.

In: Astronomy and Astrophysics, Vol. 555, A36, 05.07.2013.

Research output: Contribution to journalArticle

Kains, N, Bramich, DM, Arellano Ferro, A, Figuera Jaimes, R, Jørgensen, UG, Giridhar, S, Penny, MT, Al-Subai, K, Andersen, JM, Bozza, V, Browne, P, Burgdorf, M, Calchi Novati, S, Damerdji, Y, Diehl, C, Dodds, P, Dominik, M, Elyiv, A, Fang, XS, Giannini, E, Gu, SH, Hardis, S, Harpsøe, K, Hinse, TC, Hornstrup, A, Hundertmark, M, Jessen-Hansen, J, Juncher, D, Kerins, E, Kjeldsen, H, Korhonen, H, Liebig, C, Lund, MN, Lundkvist, M, Mancini, L, Martin, R, Mathiasen, M, Rabus, M, Rahvar, S, Ricci, D, Sahu, K, Scarpetta, G, Skottfelt, J, Snodgrass, C, Southworth, J, Surdej, J, Tregloan-Reed, J, Vilela, C, Wertz, O & Williams, A 2013, 'Estimating the parameters of globular cluster M 30 (NGC 7099) from time-series photometry', Astronomy and Astrophysics, vol. 555, A36. https://doi.org/10.1051/0004-6361/201321819
Kains, N. ; Bramich, D. M. ; Arellano Ferro, A. ; Figuera Jaimes, R. ; Jørgensen, U. G. ; Giridhar, S. ; Penny, M. T. ; Al-Subai, Khalid ; Andersen, J. M. ; Bozza, V. ; Browne, P. ; Burgdorf, M. ; Calchi Novati, S. ; Damerdji, Y. ; Diehl, C. ; Dodds, P. ; Dominik, M. ; Elyiv, A. ; Fang, X. S. ; Giannini, E. ; Gu, S. H. ; Hardis, S. ; Harpsøe, K. ; Hinse, T. C. ; Hornstrup, A. ; Hundertmark, M. ; Jessen-Hansen, J. ; Juncher, D. ; Kerins, E. ; Kjeldsen, H. ; Korhonen, H. ; Liebig, C. ; Lund, M. N. ; Lundkvist, M. ; Mancini, L. ; Martin, R. ; Mathiasen, M. ; Rabus, M. ; Rahvar, S. ; Ricci, D. ; Sahu, K. ; Scarpetta, G. ; Skottfelt, J. ; Snodgrass, C. ; Southworth, J. ; Surdej, J. ; Tregloan-Reed, J. ; Vilela, C. ; Wertz, O. ; Williams, A. / Estimating the parameters of globular cluster M 30 (NGC 7099) from time-series photometry. In: Astronomy and Astrophysics. 2013 ; Vol. 555.
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abstract = "Aims. We present the analysis of 26 nights of V and I time-series observations from 2011 and 2012 of the globular cluster M 30 (NGC 7099). We used our data to search for variable stars in this cluster and refine the periods of known variables; we then used our variable star light curves to derive values for the cluster's parameters. Methods. We used difference image analysis to reduce our data to obtain high-precision light curves of variable stars. We then estimated the cluster parameters by performing a Fourier decomposition of the light curves of RR Lyrae stars for which a good period estimate was possible. We also derived an estimate for the age of the cluster by fitting theoretical isochrones to our colour-magnitude diagram (CMD). Results. Out of 13 stars previously catalogued as variables, we find that only 4 are bona fide variables. We detect two new RR Lyrae variables, and confirm two additional RR Lyrae candidates from the literature. We also detect four other new variables, including an eclipsing blue straggler system, and an SX Phoenicis star. This amounts to a total number of confirmed variable stars in M 30 of 12. We perform Fourier decomposition of the light curves of the RR Lyrae stars to derive cluster parameters using empirical relations. We find a cluster metallicity [Fe/H]ZW =-2.01 ± 0.04, or [Fe/H]UVES =-2.11 ± 0.06, and a distance of 8.32 ± 0.20 kpc (using RR0 variables), 8.10 kpc (using one RR1 variable), and 8.35 ± 0.42 kpc (using our SX Phoenicis star detection in M 30). Fitting isochrones to the CMD, we estimate an age of 13.0 ± 1.0 Gyr for M 30.",
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author = "N. Kains and Bramich, {D. M.} and {Arellano Ferro}, A. and {Figuera Jaimes}, R. and J{\o}rgensen, {U. G.} and S. Giridhar and Penny, {M. T.} and Khalid Al-Subai and Andersen, {J. M.} and V. Bozza and P. Browne and M. Burgdorf and {Calchi Novati}, S. and Y. Damerdji and C. Diehl and P. Dodds and M. Dominik and A. Elyiv and Fang, {X. S.} and E. Giannini and Gu, {S. H.} and S. Hardis and K. Harps{\o}e and Hinse, {T. C.} and A. Hornstrup and M. Hundertmark and J. Jessen-Hansen and D. Juncher and E. Kerins and H. Kjeldsen and H. Korhonen and C. Liebig and Lund, {M. N.} and M. Lundkvist and L. Mancini and R. Martin and M. Mathiasen and M. Rabus and S. Rahvar and D. Ricci and K. Sahu and G. Scarpetta and J. Skottfelt and C. Snodgrass and J. Southworth and J. Surdej and J. Tregloan-Reed and C. Vilela and O. Wertz and A. Williams",
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TY - JOUR

T1 - Estimating the parameters of globular cluster M 30 (NGC 7099) from time-series photometry

AU - Kains, N.

AU - Bramich, D. M.

AU - Arellano Ferro, A.

AU - Figuera Jaimes, R.

AU - Jørgensen, U. G.

AU - Giridhar, S.

AU - Penny, M. T.

AU - Al-Subai, Khalid

AU - Andersen, J. M.

AU - Bozza, V.

AU - Browne, P.

AU - Burgdorf, M.

AU - Calchi Novati, S.

AU - Damerdji, Y.

AU - Diehl, C.

AU - Dodds, P.

AU - Dominik, M.

AU - Elyiv, A.

AU - Fang, X. S.

AU - Giannini, E.

AU - Gu, S. H.

AU - Hardis, S.

AU - Harpsøe, K.

AU - Hinse, T. C.

AU - Hornstrup, A.

AU - Hundertmark, M.

AU - Jessen-Hansen, J.

AU - Juncher, D.

AU - Kerins, E.

AU - Kjeldsen, H.

AU - Korhonen, H.

AU - Liebig, C.

AU - Lund, M. N.

AU - Lundkvist, M.

AU - Mancini, L.

AU - Martin, R.

AU - Mathiasen, M.

AU - Rabus, M.

AU - Rahvar, S.

AU - Ricci, D.

AU - Sahu, K.

AU - Scarpetta, G.

AU - Skottfelt, J.

AU - Snodgrass, C.

AU - Southworth, J.

AU - Surdej, J.

AU - Tregloan-Reed, J.

AU - Vilela, C.

AU - Wertz, O.

AU - Williams, A.

PY - 2013/7/5

Y1 - 2013/7/5

N2 - Aims. We present the analysis of 26 nights of V and I time-series observations from 2011 and 2012 of the globular cluster M 30 (NGC 7099). We used our data to search for variable stars in this cluster and refine the periods of known variables; we then used our variable star light curves to derive values for the cluster's parameters. Methods. We used difference image analysis to reduce our data to obtain high-precision light curves of variable stars. We then estimated the cluster parameters by performing a Fourier decomposition of the light curves of RR Lyrae stars for which a good period estimate was possible. We also derived an estimate for the age of the cluster by fitting theoretical isochrones to our colour-magnitude diagram (CMD). Results. Out of 13 stars previously catalogued as variables, we find that only 4 are bona fide variables. We detect two new RR Lyrae variables, and confirm two additional RR Lyrae candidates from the literature. We also detect four other new variables, including an eclipsing blue straggler system, and an SX Phoenicis star. This amounts to a total number of confirmed variable stars in M 30 of 12. We perform Fourier decomposition of the light curves of the RR Lyrae stars to derive cluster parameters using empirical relations. We find a cluster metallicity [Fe/H]ZW =-2.01 ± 0.04, or [Fe/H]UVES =-2.11 ± 0.06, and a distance of 8.32 ± 0.20 kpc (using RR0 variables), 8.10 kpc (using one RR1 variable), and 8.35 ± 0.42 kpc (using our SX Phoenicis star detection in M 30). Fitting isochrones to the CMD, we estimate an age of 13.0 ± 1.0 Gyr for M 30.

AB - Aims. We present the analysis of 26 nights of V and I time-series observations from 2011 and 2012 of the globular cluster M 30 (NGC 7099). We used our data to search for variable stars in this cluster and refine the periods of known variables; we then used our variable star light curves to derive values for the cluster's parameters. Methods. We used difference image analysis to reduce our data to obtain high-precision light curves of variable stars. We then estimated the cluster parameters by performing a Fourier decomposition of the light curves of RR Lyrae stars for which a good period estimate was possible. We also derived an estimate for the age of the cluster by fitting theoretical isochrones to our colour-magnitude diagram (CMD). Results. Out of 13 stars previously catalogued as variables, we find that only 4 are bona fide variables. We detect two new RR Lyrae variables, and confirm two additional RR Lyrae candidates from the literature. We also detect four other new variables, including an eclipsing blue straggler system, and an SX Phoenicis star. This amounts to a total number of confirmed variable stars in M 30 of 12. We perform Fourier decomposition of the light curves of the RR Lyrae stars to derive cluster parameters using empirical relations. We find a cluster metallicity [Fe/H]ZW =-2.01 ± 0.04, or [Fe/H]UVES =-2.11 ± 0.06, and a distance of 8.32 ± 0.20 kpc (using RR0 variables), 8.10 kpc (using one RR1 variable), and 8.35 ± 0.42 kpc (using our SX Phoenicis star detection in M 30). Fitting isochrones to the CMD, we estimate an age of 13.0 ± 1.0 Gyr for M 30.

KW - Globular clusters: individual: M 30 (NGC 7099)

KW - Stars: variables: general

KW - Stars: variables: RR Lyrae

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U2 - 10.1051/0004-6361/201321819

DO - 10.1051/0004-6361/201321819

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JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

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