TY - JOUR
T1 - Estimation of singly transiting K2 planet periods with Gaia parallaxes
AU - Sandford, Emily
AU - Espinoza, Néstor
AU - Brahm, Rafael
AU - Jordán, Andrés
N1 - Publisher Copyright:
© 2019 The Author(s).
PY - 2019/11/1
Y1 - 2019/11/1
N2 - When a planet is only observed to transit once, direct measurement of its period is impossible. It is possible, however, to constrain the periods of single transiters, and this is desirable as they are likely to represent the cold and far extremes of the planet population observed by any particular survey. Improving the accuracy with which the period of single transiters can be constrained is therefore critical to enhance the long-period planet yield of surveys. Here, we combine Gaia parallaxes with stellar models and broad-band photometry to estimate the stellar densities of K2 planet host stars, then use that stellar density information to model individual planet transits and infer the posterior period distribution. We show that the densities we infer are reliable by comparing with densities derived through asteroseismology, and apply our method to 27 validation planets of known (directly measured) period, treating each transit as if it were the only one, as well as to 12 true single transiters. When we treat eccentricity as a free parameter, we achieve a fractional period uncertainty over the true single transits of 94-58+87 per cent, and when we fix e=0, we achieve fractional period uncertainty 15-6+30 per cent, a roughly threefold improvement over typical period uncertainties of previous studies.
AB - When a planet is only observed to transit once, direct measurement of its period is impossible. It is possible, however, to constrain the periods of single transiters, and this is desirable as they are likely to represent the cold and far extremes of the planet population observed by any particular survey. Improving the accuracy with which the period of single transiters can be constrained is therefore critical to enhance the long-period planet yield of surveys. Here, we combine Gaia parallaxes with stellar models and broad-band photometry to estimate the stellar densities of K2 planet host stars, then use that stellar density information to model individual planet transits and infer the posterior period distribution. We show that the densities we infer are reliable by comparing with densities derived through asteroseismology, and apply our method to 27 validation planets of known (directly measured) period, treating each transit as if it were the only one, as well as to 12 true single transiters. When we treat eccentricity as a free parameter, we achieve a fractional period uncertainty over the true single transits of 94-58+87 per cent, and when we fix e=0, we achieve fractional period uncertainty 15-6+30 per cent, a roughly threefold improvement over typical period uncertainties of previous studies.
KW - Methods: Data analysis
KW - Methods: Statistical
KW - Planets and satellites: Fundamental parameters
KW - Stars: Planetary systems
UR - http://www.scopus.com/inward/record.url?scp=85075159155&partnerID=8YFLogxK
U2 - 10.1093/mnras/stz2348
DO - 10.1093/mnras/stz2348
M3 - Article
AN - SCOPUS:85075159155
SN - 0035-8711
VL - 489
SP - 3149
EP - 3161
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -