A small survey of UV-bright stars around the northern ecliptic pole: seeking new p-mode sdB variables for the TESS mission
Starting in 2019, the TESS mission will monitor the northern ecliptic pole for 1 year. Data will be collected at 30-minute and 2-minute cadences, and only a limited amount of slots will be reserved for targets requiring a 20- second cadence. Only the 20-second cadence is sufficient to sample p-mode...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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De Gruyter
2019-04-01
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| Series: | Open Astronomy |
| Subjects: | |
| Online Access: | https://doi.org/10.1515/astro-2019-0005 |
| _version_ | 1818716421877661696 |
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| author | Prins Saskia Telting John Østensen Roy |
| author_facet | Prins Saskia Telting John Østensen Roy |
| author_sort | Prins Saskia |
| collection | DOAJ |
| description | Starting in 2019, the TESS mission will monitor the northern ecliptic pole for 1 year. Data will be collected at 30-minute and 2-minute cadences, and only a limited amount of slots will be reserved for targets requiring a 20- second cadence. Only the 20-second cadence is sufficient to sample p-mode oscillations in sdB stars. From the seismic measurements obtained with the Kepler spacecraft we have gained a wealth of new insights in structural and rotational aspects of mainly g-mode variable sdB stars. Unfortunately only one traditional p-mode sdB variable was found in the main Kepler field. The TESS mission offers the opportunity to obtain more long-time-base coverage of p-mode sdB variables, especially at the ecliptic poles where the time-base will be longest. Thus far, there were only two known (p-mode) sdBVs around the northern ecliptic pole (β > 78): LS Dra and V366 Dra. In this paper we describe our efforts to find more.We compiled a new sample of 76 sdB candidates around the northern ecliptic pole, based on GALEX and optical colours, and we used low-resolution Balmer-line spectroscopy for classification. We identified 39 new sdB stars, of which 29 have characteristics (Teff > 28000 K or a composite spectrum) that may put them in the p-mode instability strip.With our 39 new sdB stars, we augmented the number of known sdB stars in the the northern ecliptic pole area (β> 73) by 46%. Besides these sdB stars, among our spectral classifications are various sdO stars, He-sdB stars, blue horizontal-branch stars, white dwarfs, cataclysmic variables and main sequence B stars. We obtained time-resolved photometry of most of the p-mode sdB candidates, and found one new sdBV, J19384+5824, with a moderately high pulsation amplitude of ≥ 9 mmag. |
| first_indexed | 2024-12-17T19:19:00Z |
| format | Article |
| id | doaj.art-f44b4b187174448b8e392990f6e6f990 |
| institution | Directory Open Access Journal |
| issn | 2543-6376 |
| language | English |
| last_indexed | 2024-12-17T19:19:00Z |
| publishDate | 2019-04-01 |
| publisher | De Gruyter |
| record_format | Article |
| series | Open Astronomy |
| spelling | doaj.art-f44b4b187174448b8e392990f6e6f9902022-12-21T21:35:39ZengDe GruyterOpen Astronomy2543-63762019-04-01281616710.1515/astro-2019-0005astro-2019-0005A small survey of UV-bright stars around the northern ecliptic pole: seeking new p-mode sdB variables for the TESS missionPrins Saskia0Telting John1Østensen Roy2Mercator Telescope, Apartado de Correos 20, 38700 Santa Cruz de La Palma, Spain; Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001Leuven, BelgiumNordic Optical Telescope, Rambla José Ana Fernández Pérez 7, 38711Breña Baja, SpainDepartment of Physics, Astronomy, and Materials Science, Missouri State University, Springfield, MO 65804, United States of AmericaStarting in 2019, the TESS mission will monitor the northern ecliptic pole for 1 year. Data will be collected at 30-minute and 2-minute cadences, and only a limited amount of slots will be reserved for targets requiring a 20- second cadence. Only the 20-second cadence is sufficient to sample p-mode oscillations in sdB stars. From the seismic measurements obtained with the Kepler spacecraft we have gained a wealth of new insights in structural and rotational aspects of mainly g-mode variable sdB stars. Unfortunately only one traditional p-mode sdB variable was found in the main Kepler field. The TESS mission offers the opportunity to obtain more long-time-base coverage of p-mode sdB variables, especially at the ecliptic poles where the time-base will be longest. Thus far, there were only two known (p-mode) sdBVs around the northern ecliptic pole (β > 78): LS Dra and V366 Dra. In this paper we describe our efforts to find more.We compiled a new sample of 76 sdB candidates around the northern ecliptic pole, based on GALEX and optical colours, and we used low-resolution Balmer-line spectroscopy for classification. We identified 39 new sdB stars, of which 29 have characteristics (Teff > 28000 K or a composite spectrum) that may put them in the p-mode instability strip.With our 39 new sdB stars, we augmented the number of known sdB stars in the the northern ecliptic pole area (β> 73) by 46%. Besides these sdB stars, among our spectral classifications are various sdO stars, He-sdB stars, blue horizontal-branch stars, white dwarfs, cataclysmic variables and main sequence B stars. We obtained time-resolved photometry of most of the p-mode sdB candidates, and found one new sdBV, J19384+5824, with a moderately high pulsation amplitude of ≥ 9 mmag.https://doi.org/10.1515/astro-2019-0005asteroseismologystars: oscillationssubdwarfs |
| spellingShingle | Prins Saskia Telting John Østensen Roy A small survey of UV-bright stars around the northern ecliptic pole: seeking new p-mode sdB variables for the TESS mission Open Astronomy asteroseismology stars: oscillations subdwarfs |
| title | A small survey of UV-bright stars around the northern ecliptic pole: seeking new p-mode sdB variables for the TESS mission |
| title_full | A small survey of UV-bright stars around the northern ecliptic pole: seeking new p-mode sdB variables for the TESS mission |
| title_fullStr | A small survey of UV-bright stars around the northern ecliptic pole: seeking new p-mode sdB variables for the TESS mission |
| title_full_unstemmed | A small survey of UV-bright stars around the northern ecliptic pole: seeking new p-mode sdB variables for the TESS mission |
| title_short | A small survey of UV-bright stars around the northern ecliptic pole: seeking new p-mode sdB variables for the TESS mission |
| title_sort | small survey of uv bright stars around the northern ecliptic pole seeking new p mode sdb variables for the tess mission |
| topic | asteroseismology stars: oscillations subdwarfs |
| url | https://doi.org/10.1515/astro-2019-0005 |
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