EDP Sciences
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Erratum
This article is an erratum for: [this article]

Issue
A&A
Volume 600, April 2017
Article Number C1
Number of page(s) 2
Section Planets and planetary systems
DOI https://doi.org/10.1051/0004-6361/201629699e
Published online 17 March 2017

1. Reported ephemeris

Our reported mid-transit time T0 contains a shift when compared to other data sets. After checking our analysis we found an error in the correction of the Kepler BJD times. In the original article we wrote that our determined T0 is given in BJDUTC. However, this is only true for Kepler data up to release 19. For data releases after this (data release 20/21 onwards), the reported times in the Kepler data are correctly given in BJDTDB1. We checked the Kepler data we used and confirm that all the Kepler data has times in BJDTDB. Thus, our reported T0 is in BJDTDB as well.

We have changed Table 1 and Fig. 1 of the original paper and include the new versions in this corrigendum. The only difference is that we have not applied the subtraction of Δt = 66.184 s to Tref of Sanchis-Ojeda & Winn to convert it into BJDUTC, and we now correctly state that our value of T0 is given in BJDTDB; we note that the actual numerical value of T0 does not change. The other results in our original paper are not affected by this correction.

thumbnail Fig. 1

Measurements of mid-transit times from 206Kepler transits. The (magenta) line represents a first-order polynomial fit to the error-weighted measurements. The lower panel shows the residuals with outliers removed. See caption and text of original paper for more detailed explanations.

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2. Difference to Tref

In Sect. 3.1 of the original paper we speculate on the origin of the time difference of about two minutes between T0 and Tref; however, we were not able to provide a convincing answer to this inconsistency. After correction for our mistake concerning the time system, this difference ΔT between T0 and Tref is reduced by Δt = 66.184 s to ΔT = 64.17 s. We believe the remaining difference ΔT is caused by the fact that Tref as given by Sanchis-Ojeda & Winn (2011) is reported to be in BJDTDB but is actually BJDUTC. In this case we would have to correct Tref by adding Δt to convert it into BJDTDB, and ΔT would reduce to approximately −2 s. This assumption is reasonable because Sanchis-Ojeda & Winn published their paper in 2011, before the Kepler release notes 19 had been published; therefore, the problem of erroneous Kepler times was not yet known and the headers of the Kepler data files incorrectly stated that the times were in BJDTDB2.

Table 1

Reference and revised ephemeris.

With this correction, the time shift of about one minute for early transit numbers in Fig. 1 virtually vanishes. Thus, we conclude that Tref is most likely BJDUTC; however, we have not changed this in Table 1 to be consistent with the table in Sanchis-Ojeda & Winn (2011) from whence this value is taken.


2

We contacted Joshua Winn, who confirmed that this conclusion is plausible (Winn 2017, priv. comm.). When writing their paper Sanchis-Ojeda & Winn (2011), they had no reason to suspect any problems with the Kepler time stamps.

References


© ESO, 2017

All Tables

Table 1

Reference and revised ephemeris.

All Figures

thumbnail Fig. 1

Measurements of mid-transit times from 206Kepler transits. The (magenta) line represents a first-order polynomial fit to the error-weighted measurements. The lower panel shows the residuals with outliers removed. See caption and text of original paper for more detailed explanations.

Open with DEXTER
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