Effective temperatures of cataclysmic-variable white dwarfs as a probe of their evolution

A. F. Pala, B. T. Gänsicke, D. Townsley, D. Boyd, M. J. Cook, D. De Martino, P. Godon, J. B. Haislip, A. A. Henden, Ivan - Hubeny, K. M. Ivarsen, S. Kafka, C. Knigge, A. P. LaCluyze, K. S. Long, T. R. Marsh, B. Monard, J. P. Moore, G. Myers, P. Nelson & 12 others D. Nogami, A. Oksanen, R. Pickard, G. Poyner, D. E. Reichart, D. Rodriguez Perez, M. R. Schreiber, J. Shears, E. M. Sion, R. Stubbings, P. Szkody, M. Zorotovic

Research output: Contribution to journalArticle

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Abstract

We present HST spectroscopy for 45 cataclysmic variables (CVs), observed with HST/COS and HST/STIS. For 36 CVs, the white dwarf is recognisable through its broad Ly α absorption profile and we measure the white dwarf effective temperatures (Teff) by fitting the HST data assuming log g = 8.35, which corresponds to the average mass for CV white dwarfs (≃0.8M). Our results nearly double the number of CV white dwarfs with an accurate temperature measurement. We find that CVs above the period gap have, on average, higher temperatures (〈 Teff〉 ≃ 23 000 K) and exhibit much more scatter compared to those below the gap (〈Teff〉 ≃ 15 000 K). While this behaviour broadly agrees with theoretical predictions, some discrepancies are present: (i) all our new measurements above the gap are characterized by lower temperatures (Teff ≃ 16 000-26 000 K) than predicted by the present-day CV population models (Teff ≃ 38 000-43 000 K); (ii) our results below the gap are not clustered in the predicted narrow track and exhibit in particular a relatively large spread near the period minimum, which may point to some shortcomings in the CV evolutionary models. Finally, in the standard model of CV evolution, reaching the minimum period, CVs are expected to evolve back towards longer periods with mean accretion rates M ≲ 2 × 10-11M yr-1, corresponding to Teff ≲ 11 500 K. We do not unambiguously identify any such system in our survey, suggesting that this major component of the predicted CV population still remains elusive to observations.

Original languageEnglish (US)
Pages (from-to)2855-2878
Number of pages24
JournalMonthly Notices of the Royal Astronomical Society
Volume466
Issue number3
DOIs
StatePublished - 2017

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cataclysmic variables
probe
probes
temperature
spectroscopy
accretion
prediction
temperature measurement

Keywords

  • Novae, cataclysmic variables
  • Stars: fundamental parameters
  • Ultraviolet: stars
  • White dwarfs

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Pala, A. F., Gänsicke, B. T., Townsley, D., Boyd, D., Cook, M. J., De Martino, D., ... Zorotovic, M. (2017). Effective temperatures of cataclysmic-variable white dwarfs as a probe of their evolution. Monthly Notices of the Royal Astronomical Society, 466(3), 2855-2878. https://doi.org/10.1093/mnras/stw3293

Effective temperatures of cataclysmic-variable white dwarfs as a probe of their evolution. / Pala, A. F.; Gänsicke, B. T.; Townsley, D.; Boyd, D.; Cook, M. J.; De Martino, D.; Godon, P.; Haislip, J. B.; Henden, A. A.; Hubeny, Ivan -; Ivarsen, K. M.; Kafka, S.; Knigge, C.; LaCluyze, A. P.; Long, K. S.; Marsh, T. R.; Monard, B.; Moore, J. P.; Myers, G.; Nelson, P.; Nogami, D.; Oksanen, A.; Pickard, R.; Poyner, G.; Reichart, D. E.; Rodriguez Perez, D.; Schreiber, M. R.; Shears, J.; Sion, E. M.; Stubbings, R.; Szkody, P.; Zorotovic, M.

In: Monthly Notices of the Royal Astronomical Society, Vol. 466, No. 3, 2017, p. 2855-2878.

Research output: Contribution to journalArticle

Pala, AF, Gänsicke, BT, Townsley, D, Boyd, D, Cook, MJ, De Martino, D, Godon, P, Haislip, JB, Henden, AA, Hubeny, I, Ivarsen, KM, Kafka, S, Knigge, C, LaCluyze, AP, Long, KS, Marsh, TR, Monard, B, Moore, JP, Myers, G, Nelson, P, Nogami, D, Oksanen, A, Pickard, R, Poyner, G, Reichart, DE, Rodriguez Perez, D, Schreiber, MR, Shears, J, Sion, EM, Stubbings, R, Szkody, P & Zorotovic, M 2017, 'Effective temperatures of cataclysmic-variable white dwarfs as a probe of their evolution', Monthly Notices of the Royal Astronomical Society, vol. 466, no. 3, pp. 2855-2878. https://doi.org/10.1093/mnras/stw3293
Pala, A. F. ; Gänsicke, B. T. ; Townsley, D. ; Boyd, D. ; Cook, M. J. ; De Martino, D. ; Godon, P. ; Haislip, J. B. ; Henden, A. A. ; Hubeny, Ivan - ; Ivarsen, K. M. ; Kafka, S. ; Knigge, C. ; LaCluyze, A. P. ; Long, K. S. ; Marsh, T. R. ; Monard, B. ; Moore, J. P. ; Myers, G. ; Nelson, P. ; Nogami, D. ; Oksanen, A. ; Pickard, R. ; Poyner, G. ; Reichart, D. E. ; Rodriguez Perez, D. ; Schreiber, M. R. ; Shears, J. ; Sion, E. M. ; Stubbings, R. ; Szkody, P. ; Zorotovic, M. / Effective temperatures of cataclysmic-variable white dwarfs as a probe of their evolution. In: Monthly Notices of the Royal Astronomical Society. 2017 ; Vol. 466, No. 3. pp. 2855-2878.
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abstract = "We present HST spectroscopy for 45 cataclysmic variables (CVs), observed with HST/COS and HST/STIS. For 36 CVs, the white dwarf is recognisable through its broad Ly α absorption profile and we measure the white dwarf effective temperatures (Teff) by fitting the HST data assuming log g = 8.35, which corresponds to the average mass for CV white dwarfs (≃0.8M⊙). Our results nearly double the number of CV white dwarfs with an accurate temperature measurement. We find that CVs above the period gap have, on average, higher temperatures (〈 Teff〉 ≃ 23 000 K) and exhibit much more scatter compared to those below the gap (〈Teff〉 ≃ 15 000 K). While this behaviour broadly agrees with theoretical predictions, some discrepancies are present: (i) all our new measurements above the gap are characterized by lower temperatures (Teff ≃ 16 000-26 000 K) than predicted by the present-day CV population models (Teff ≃ 38 000-43 000 K); (ii) our results below the gap are not clustered in the predicted narrow track and exhibit in particular a relatively large spread near the period minimum, which may point to some shortcomings in the CV evolutionary models. Finally, in the standard model of CV evolution, reaching the minimum period, CVs are expected to evolve back towards longer periods with mean accretion rates M ≲ 2 × 10-11M⊙ yr-1, corresponding to Teff ≲ 11 500 K. We do not unambiguously identify any such system in our survey, suggesting that this major component of the predicted CV population still remains elusive to observations.",
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T1 - Effective temperatures of cataclysmic-variable white dwarfs as a probe of their evolution

AU - Pala, A. F.

AU - Gänsicke, B. T.

AU - Townsley, D.

AU - Boyd, D.

AU - Cook, M. J.

AU - De Martino, D.

AU - Godon, P.

AU - Haislip, J. B.

AU - Henden, A. A.

AU - Hubeny, Ivan -

AU - Ivarsen, K. M.

AU - Kafka, S.

AU - Knigge, C.

AU - LaCluyze, A. P.

AU - Long, K. S.

AU - Marsh, T. R.

AU - Monard, B.

AU - Moore, J. P.

AU - Myers, G.

AU - Nelson, P.

AU - Nogami, D.

AU - Oksanen, A.

AU - Pickard, R.

AU - Poyner, G.

AU - Reichart, D. E.

AU - Rodriguez Perez, D.

AU - Schreiber, M. R.

AU - Shears, J.

AU - Sion, E. M.

AU - Stubbings, R.

AU - Szkody, P.

AU - Zorotovic, M.

PY - 2017

Y1 - 2017

N2 - We present HST spectroscopy for 45 cataclysmic variables (CVs), observed with HST/COS and HST/STIS. For 36 CVs, the white dwarf is recognisable through its broad Ly α absorption profile and we measure the white dwarf effective temperatures (Teff) by fitting the HST data assuming log g = 8.35, which corresponds to the average mass for CV white dwarfs (≃0.8M⊙). Our results nearly double the number of CV white dwarfs with an accurate temperature measurement. We find that CVs above the period gap have, on average, higher temperatures (〈 Teff〉 ≃ 23 000 K) and exhibit much more scatter compared to those below the gap (〈Teff〉 ≃ 15 000 K). While this behaviour broadly agrees with theoretical predictions, some discrepancies are present: (i) all our new measurements above the gap are characterized by lower temperatures (Teff ≃ 16 000-26 000 K) than predicted by the present-day CV population models (Teff ≃ 38 000-43 000 K); (ii) our results below the gap are not clustered in the predicted narrow track and exhibit in particular a relatively large spread near the period minimum, which may point to some shortcomings in the CV evolutionary models. Finally, in the standard model of CV evolution, reaching the minimum period, CVs are expected to evolve back towards longer periods with mean accretion rates M ≲ 2 × 10-11M⊙ yr-1, corresponding to Teff ≲ 11 500 K. We do not unambiguously identify any such system in our survey, suggesting that this major component of the predicted CV population still remains elusive to observations.

AB - We present HST spectroscopy for 45 cataclysmic variables (CVs), observed with HST/COS and HST/STIS. For 36 CVs, the white dwarf is recognisable through its broad Ly α absorption profile and we measure the white dwarf effective temperatures (Teff) by fitting the HST data assuming log g = 8.35, which corresponds to the average mass for CV white dwarfs (≃0.8M⊙). Our results nearly double the number of CV white dwarfs with an accurate temperature measurement. We find that CVs above the period gap have, on average, higher temperatures (〈 Teff〉 ≃ 23 000 K) and exhibit much more scatter compared to those below the gap (〈Teff〉 ≃ 15 000 K). While this behaviour broadly agrees with theoretical predictions, some discrepancies are present: (i) all our new measurements above the gap are characterized by lower temperatures (Teff ≃ 16 000-26 000 K) than predicted by the present-day CV population models (Teff ≃ 38 000-43 000 K); (ii) our results below the gap are not clustered in the predicted narrow track and exhibit in particular a relatively large spread near the period minimum, which may point to some shortcomings in the CV evolutionary models. Finally, in the standard model of CV evolution, reaching the minimum period, CVs are expected to evolve back towards longer periods with mean accretion rates M ≲ 2 × 10-11M⊙ yr-1, corresponding to Teff ≲ 11 500 K. We do not unambiguously identify any such system in our survey, suggesting that this major component of the predicted CV population still remains elusive to observations.

KW - Novae, cataclysmic variables

KW - Stars: fundamental parameters

KW - Ultraviolet: stars

KW - White dwarfs

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U2 - 10.1093/mnras/stw3293

DO - 10.1093/mnras/stw3293

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VL - 466

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JO - Monthly Notices of the Royal Astronomical Society

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