A lower mass for the exoplanet WASP-21b
We present high-precision transit observations of the exoplanet WASP-21b, obtained with the Rapid Imager to Search for Exoplanets instrument mounted on the 2.0-m Liverpool Telescope. A transit model is fitted, coupled with a Markov chain Monte Carlo routine, to derive accurate system parameters. The...
| Main Authors: | , , , , , , , |
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| Format: | Journal article |
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2011
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| _version_ | 1797056454660718592 |
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| author | Barros, S Pollacco, D Gibson, N Howarth, I Keenan, F Simpson, E Skillen, I Steele, I |
| author_facet | Barros, S Pollacco, D Gibson, N Howarth, I Keenan, F Simpson, E Skillen, I Steele, I |
| author_sort | Barros, S |
| collection | OXFORD |
| description | We present high-precision transit observations of the exoplanet WASP-21b, obtained with the Rapid Imager to Search for Exoplanets instrument mounted on the 2.0-m Liverpool Telescope. A transit model is fitted, coupled with a Markov chain Monte Carlo routine, to derive accurate system parameters. The two new high-precision transits allow us to estimate the stellar density directly from the light curve. Our analysis suggests that WASP-21 is evolving off the main sequence which led to a previous overestimation of the stellar density. Using isochrone interpolation, we find a stellar mass of 0.86 ± 0.04M⊙, which is significantly lower than previously reported (1.01 ± 0.03M⊙). Consequently, we find a lower planetary mass of 0.27 ± 0.01MJup. A lower inclination (874 ± 03) is also found for the system than previously reported, resulting in a slightly larger stellar (R*= 1.10 ± 0.03R⊙) and planetary radius (Rp= 1.14 ± 0.04RJup). The planet radius suggests a hydrogen/helium composition with no core which strengthens the correlation between planetary density and host star metallicity. A new ephemeris is determined for the system, i.e. T0= 2455084.51974 ± 0.00020 (HJD) and P= 4.3225060 ± 0.0000031d. We found no transit timing variations in WASP-21b. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS. |
| first_indexed | 2024-03-06T19:23:11Z |
| format | Journal article |
| id | oxford-uuid:1acf922f-6abe-4e97-9e8e-7dc0df109640 |
| institution | University of Oxford |
| last_indexed | 2024-03-06T19:23:11Z |
| publishDate | 2011 |
| record_format | dspace |
| spelling | oxford-uuid:1acf922f-6abe-4e97-9e8e-7dc0df1096402022-03-26T10:56:58ZA lower mass for the exoplanet WASP-21bJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:1acf922f-6abe-4e97-9e8e-7dc0df109640Symplectic Elements at Oxford2011Barros, SPollacco, DGibson, NHowarth, IKeenan, FSimpson, ESkillen, ISteele, IWe present high-precision transit observations of the exoplanet WASP-21b, obtained with the Rapid Imager to Search for Exoplanets instrument mounted on the 2.0-m Liverpool Telescope. A transit model is fitted, coupled with a Markov chain Monte Carlo routine, to derive accurate system parameters. The two new high-precision transits allow us to estimate the stellar density directly from the light curve. Our analysis suggests that WASP-21 is evolving off the main sequence which led to a previous overestimation of the stellar density. Using isochrone interpolation, we find a stellar mass of 0.86 ± 0.04M⊙, which is significantly lower than previously reported (1.01 ± 0.03M⊙). Consequently, we find a lower planetary mass of 0.27 ± 0.01MJup. A lower inclination (874 ± 03) is also found for the system than previously reported, resulting in a slightly larger stellar (R*= 1.10 ± 0.03R⊙) and planetary radius (Rp= 1.14 ± 0.04RJup). The planet radius suggests a hydrogen/helium composition with no core which strengthens the correlation between planetary density and host star metallicity. A new ephemeris is determined for the system, i.e. T0= 2455084.51974 ± 0.00020 (HJD) and P= 4.3225060 ± 0.0000031d. We found no transit timing variations in WASP-21b. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS. |
| spellingShingle | Barros, S Pollacco, D Gibson, N Howarth, I Keenan, F Simpson, E Skillen, I Steele, I A lower mass for the exoplanet WASP-21b |
| title | A lower mass for the exoplanet WASP-21b |
| title_full | A lower mass for the exoplanet WASP-21b |
| title_fullStr | A lower mass for the exoplanet WASP-21b |
| title_full_unstemmed | A lower mass for the exoplanet WASP-21b |
| title_short | A lower mass for the exoplanet WASP-21b |
| title_sort | lower mass for the exoplanet wasp 21b |
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