GRANTS

Stellar Pulsation, space photometry, exoplanets (SPEX)


PD-123910: Evolved compact stars in the era of photometric space missions (2017-2020)

PI: Zsófia Bognár


Summary:

This research project aims at learning more about evolved compact stars, namely white dwarf and hot subdwarf stars. Our Sun, as the majority of the stars, will also become a white dwarf eventually, while hot subdwarfs evolve following a different path. We assume that hot subdwarfs are products of evolution in a binary system, or the presence of substellar companion(s) influenced their evolution. Such stellar or substellar (e.g. planet-sized) companions can be discovered by investigating the pulsations of the compact star or with the light variations caused by their passing in front of each other.

Excitation of pulsations in the stellar interiors of these objects are common in specific temperature ranges, which offers a unique opportunity to study their structure, rotation, and the dynamical processes operating in them. The best way of such so-called asteroseismic investigations is the use of continuous, long time-base, high-quality space-based data. In this project, the PI intends to play an active role in the activities of the NASA TESS (Transiting Exoplanet Survey Satellite) photometric space mission, which is planned to observe more than 4000 evolved compact stars, including known pulsators and candidates. Besides the analyses of space-based data, the PI will also perform ground-based complementary observations to gain more information on the light variations of TESS targets and to learn more about the pulsational behaviour of the members of the most populated group of white dwarf variables, the ZZ Ceti stars. This project will strengthen Hungary's participation in the compact variable studies both in Europe and worldwide.

Project no. 123910 has been implemented with the support provided from the National Research, Development and Innovation Fund of Hungary, financed under the P_17 funding scheme.


Publications:

Papers in ISI journals:

  1. 14. „TESS first look at evolved compact pulsators. Known ZZ Ceti stars of the southern ecliptic hemisphere as seen by TESS”
    Bognár, Zs.; Kawaler, S. D.; Bell, K. J. et al.: 2020, A&A, 838, A82, ADS

  2. 13. „Solar System Objects Observed with TESS - First Data Release: Bright Main-belt and Trojan Asteroids from the Southern Survey”
    Pál, A.; Szakáts, R.; Kiss, Cs.; Bódi, A.; Bognár, Zs. et al.: 2020, ApJS, 247, id.26, ADS

  3. 12. „TESS first look at evolved compact pulsators: Discovery and asteroseismic probing of the g-mode hot B subdwarf pulsator EC 21494-7018”
    Charpinet, S.; Brassard, P.; Fontaine, G.; Van Grootel, V.; Zong, W.; Giammichele, N.; Heber, U.; Bognár, Zs. et al.: 2019, A&A, 632, A90, ADS

  4. 11. „TESS first look at evolved compact pulsators: asteroseismology of the pulsating helium-atmosphere white dwarf TIC 257459955”
    Bell, K. J.; Córsico, A. H.; Bischoff-Kim, A. ... Bognár, Zs. et al.: 2019, A&A, 632, A42, ADS

  5. 10. „The first view of delta Scuti and gamma Doradus stars with the TESS mission”
    Antoci, V.; Cunha, M. S.; Bowman, D. M. ... Bognár, Zs. et al.: 2019, MNRAS, 490, 4040, ADS

  6. 9. „Rotation and pulsation in Ap stars: first light results from TESS sectors 1 and 2”
    Cunha, M. S.; Antoci, V.; Holdsworth, D. L.; Kurtz, D. W.; Balona, L. A.; Bognár, Zs. et al.: 2019, MNRAS, 487, 3523, ADS

  7. 8. „One new variable candidate and six nonvariable stars at the ZZ Ceti instability strip”
    Bognár, Zs.; Kalup, Cs.; Sódor, Á.: 2019, Acta Astronomica, 69, 55, ADS

  8. 7. „GD358: three decades of observations for the in-depth asteroseismology of a DBV star”
    Bischoff-Kim, A.; Provencal, J. L.; Bradley, P. A. ... Bognár, Zs. et al.: 2019, ApJ, 871, id.13, ADS

  9. 6. „K2 Observations of SN 2018oh Reveal a Two-Component Rising Light Curve for a Type Ia Supernova”
    Dimitriadis, G.; Foley, R. J.; Rest, A. ... Bognár, Zs. et al.: 2019, ApJL, 870, L1, ADS

  10. 5. „Photometric and Spectroscopic Properties of Type Ia Supernova 2018oh with Early Excess Emission from the Kepler 2 Observations”
    Li, W.; Wang, X.; Vinkó, J. ... Bognár, Zs. et al.: 2019, ApJ, 870, id.12, ADS

  11. 4. „Wandering near the red edge: photometric observations of three cool ZZ Ceti stars”
    Bognár, Zs.; Paparó, M.; Sódor, Á.; Jenei, D. I.; Kalup, Cs. et al.: 2019, MNRAS, 482, 4018, ADS

  12. 3. „Searching for new white dwarf pulsators for TESS observations at Konkoly Observatory”
    Bognár, Zs.; Kalup, Cs.; Sódor, Á.; Charpinet, S.; Hermes, J. J.: 2018, MNRAS, 478, 2676, ADS

  13. 2. „The Delta Scuti star 38 Eri from the ground and from space”
    Paparó, M.; Kolláth, Z.; Shobbrook, R. R.; Matthews, J. M.; Antoci, V.; Benkő, J. M.; Park, N.-K.; Mirtorabi, M. T.; Luedeke, K.; Kusakin, A.; Bognár, Zs. et al.: 2018, MNRAS, 477, 4362, ADS

  14. 1. „Multi-technique investigation of the binary fraction among A-F type candidate hybrid variable stars discovered by Kepler”
    Lampens, P.; Frémat, Y.; Vermeylen, L.; Sódor, Á.; Skarka, M.; De Cat, P.; Bognár, Zs. et al.: 2018, A&A, 610, A17, ADS


Dissemination of our results: popular science articles, public lectures, posters, conference proceedings:

  1. 12. „A hét kutatója” rovat: Interjú Sódorné Bognár Zsófiával: Szeizmológia az égen
    Trupka Zoltán: 2020, Élet és Tudomány, 2020/12, 370-371. o. (pdf)

  2. 11. „The planet-host pulsating star HR 8799 as seen by BRITE”
    Sódor, Á.; Bognár, Zs.: 2020, Proceedings of the conference Stars and their Variability Observed from Space, held in Vienna on August 19-23, 2019. Eds.: C. Neiner, W. W. Weiss, D. Baade, R. E. Griffin, C. C. Lovekin, A. F. J. Moffat. University of Vienna, pp.91-92, ADS

  3. 10. „Pre-TESS observations of pulsating white dwarf stars at Konkoly Observatory”
    Bognár, Zs.; Kalup, Cs.; Sódor, Á.: 2020, Proceedings of the conference Stars and their Variability Observed from Space, held in Vienna on August 19-23, 2019. Eds.: C. Neiner, W. W. Weiss, D. Baade, R. E. Griffin, C. C. Lovekin, A. F. J. Moffat. University of Vienna, pp.25-26, ADS

  4. 9. „Pre-TESS observations of pulsating white dwarf stars at Konkoly Observatory”
    Bognár, Zs.; Kalup, Cs.; Sódor, Á., poster, „Stars and their variability observed from space” conference (Vienna, August 19-23, 2019) (pdf)

  5. 8. „The spectroscopic multiplicity fraction in a sample of (candidate) hybrid A- and F-type stars from the Kepler mission”
    P. Lampens; L. Vermeylen; P. De Cat; Á. Sódor; Zs. Bognár; Y. Frémat; M. Skarka; H. Lehmann; A. Samadi; L. Fox-Machado; S. Joshi, poster, „Stars and their variability observed from space” conference (Vienna, August 19-23, 2019) (pdf)

  6. 7. „The planet-host pulsating star HR 8799 as seen by MOST and BRITE”
    Sódor, Á.; Bognár, Zs., poster, „Stars and their variability observed from space” conference (Vienna, August 19-23, 2019) (pdf)

  7. 6. „Radial velocity monitoring of (candidate) hybrid A- and F-type stars from the Kepler mission”
    P. Lampens; L. Vermeylen; P. De Cat; Á. Sódor; Zs. Bognár; Y. Frémat; M. Skarka; H. Lehmann, poster, Physics of Oscillating STars (Banyuls-sur-mer (France), September 03-07, 2018) (pdf)

  8. 5. „Searching for new DA white dwarf pulsators at Konkoly Observatory”
    Bognár, Zs.; Kalup, Cs.; Sódor, Á., poster, XXXth General Assembly of the International Astronomical Union (Vienna, August 20-31, 2018) (pdf)

  9. 4. „Efficient Frequency Identification in Coherent Variable Stars”
    Sódor, Á., Bognár, Zs.; Skarka, M., poster, XXXth General Assembly of the International Astronomical Union (Vienna, August 20-31, 2018) (pdf)

  10. 3. „Pulzáló fehér törpecsillagok anatómiája”
    Bognár, Zs.: 2018, Természet Világa, 149/7, 308 (html)

  11. 2. 2017, 23 November: „Latest news on white dwarf pulsators in the light of space- and ground-based observations” – seminar at Konkoly Observatory, Budapest, Hungary (pdf)

  12. 1. 2017, 11 November: „Kompakt pulzátorok a fotometriai űrtávcsövek korában – célpontban a fehér törpecsillagok” (in Hungarian) – a Változócsillag Szakcsoport találkozója a Magyar Csillagászati Egyesület Változócsillag Szakcsoportja (MCSE VCSSZ) és az MTA CSFK Konkoly Thege Miklós Csillagászati Intézet közös szervezésében, Budapest (pdf)


Other results of project:
The following prizes and grants were awarded to the PI during the project period:

  1. 2. „Young Researcher Award” of the Hungarian Academy of Sciences (2020) (link)

  2. 1. „János Bolyai Research Scholarship” of the Hungarian Academy of Sciences (2020-2023) (link)