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NGTS-8b and NGTS-9b: two non-inflated hot-Jupiters

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journal contribution
posted on 23.04.2020, 13:03 by Jean C Costes, Christopher A Watson, Claudia Belardi, Ian P Braker, Matthew R Burleigh, Sarah L Casewell, Philipp Eigmüller, Maximilian N Günther, James AG Jackman, Louise D Nielsen, Maritza G Soto, Oliver Turner, David R Anderson, Daniel Bayliss, François Bouchy, Joshua T Briegal, Edward M Bryant, Juan Cabrera, Alexander Chaushev, Szilard Csizmadia, Anders Erikson, Samuel Gill, Edward Gillen, Michael R Goad, Matthew J Hooton, James S Jenkins, James McCormac, Maximiliano Moyano, Didier Queloz, Heike Rauer, Liam Raynard, Alexis MS Smith, Andrew PG Thompson, Rosanna H Tilbrook, Stephane Udry, Jose I Vines, Richard G West, Peter J Wheatley
We report the discovery, by the Next Generation Transit Survey (NGTS), of two hot-Jupiters NGTS-8b and NGTS-9b. These orbit a V = 13.68 K0V star (Teff = 5241 +/- 50 K) with a period of 2.49970 days, and a V = 12.80 F8V star (Teff = 6330 +/- 130 K) in 4.43527 days, respectively. The transits were independently verified by follow-up photometric observations with the SAAO 1.0-m and Euler telescopes, and we report on the planetary parameters using HARPS, FEROS and CORALIE radial velocities. NGTS-8b has a mass, 0.93 +0.04 -0.03 MJ and a radius, 1.09 +/- 0.03 RJ similar to Jupiter, resulting in a density of 0.89 +0.08 -0.07 g cm-3. This is in contrast to NGTS-9b, which has a mass of 2.90 +/- 0.17 MJ and a radius of 1.07 +/- 0.06 RJ , resulting in a much greater density of 2.93 +0.53 -0.49 g cm-3. Statistically, the planetary parameters put both objects in the regime where they would be expected to exhibit larger than predicted radii. However, we find that their radii are in agreement with predictions by theoretical non-inflated models.

Funding

The contributions at the University of Leicester by MRG and MRB have been supported by STFC through consolidated grant ST/N000757/1. CAW acknowledges support from the STFC grant ST/P000312/1.

History

Citation

Monthly Notices of the Royal Astronomical Society, Volume 491, Issue 2, January 2020, Pages 2834–2844, https://doi.org/10.1093/mnras/stz3140

Version

VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society

Volume

491

Issue

2

Pagination

2834–2844

Publisher

Oxford University Press (OUP)

issn

0035-8711

eissn

1365-2966

Acceptance date

29/10/2019

Copyright date

2019

Available date

20/11/2019

Publisher version

https://academic.oup.com/mnras/article/491/2/2834/5634272

Language

en