DEEP MMT* TRANSIT SURVEY OF THE OPEN CLUSTER M37 IV: LIMIT ON THE FRACTION OF STARS WITH PLANETS AS SMALL AS 0.3R(J)

作者：Hartman J D^*; Gaudi B S; Holman M J; McLeod B A; Stanek K Z; Barranco J A; Pinsonneault M H; Meibom S; Kalirai J S

来源：Astrophysical Journal, 2009, 695(1): 336-356.

DOI：10.1088/0004-637X/695/1/336

• open clusters and associations: individual (M37)
• planetary systems
• surveys

We present the results of a deep (15 less than or similar to r less than or similar to 23), 20 night survey for transiting planets in the intermediate-age open cluster M37 (NGC 2099) using the Megacam wide-field mosaic CCD camera on the 6.5 m MMT. We do not detect any transiting planets among the similar to 1450 observed cluster members. We do, however, identify a similar to 1R(J) candidate planet transiting a 0.8 M-circle dot Galactic field star with a period of 0.77 days. The source is faint (V = 19.85 mag) and has an expected velocity semiamplitude of K similar to 220 m s(-1) (M/M-J). We conduct Monte Carlo transit injection and recovery simulations to calculate the 95% confidence upper limit on the fraction of cluster members and field stars with planets as a function of planetary radius and orbital period. Assuming a uniform logarithmic distribution in the orbital period, we find that < 1.1%, < 2.7%, and < 8.3% of cluster members have 1.0R(J) planets within extremely hot Jupiter (EHJ; 0.4 < P < 1.0 day), very hot Jupiter (VHJ; 1.0 < P < 3.0 day), and hot Jupiter (HJ; 3.0 < P < 5.0 day) period ranges, respectively. For 0.5R(J) planets, the limits are less than 3.2% and less than 21% for EHJ and VHJ period ranges, respectively, while for 0.35R(J) planets we can only place an upper limit of less than 25% on the EHJ period range. For a sample of 7814 Galactic field stars, consisting primarily of FGKM dwarfs, we place 95% upper limits of < 0.3%, < 0.8%, and < 2.7% on the fraction of stars with a 1.0R(J) EHJ, VHJ, and HJ, respectively, assuming that the candidate planet is not genuine. If the candidate is genuine, the frequency of similar to 1.0R(J) planets in the EHJ period range is 0.002% < f(EHJ) < 0.5% with 95% confidence. We place limits of < 1.4%, < 8.8%, and < 47% for 0.5R(J) planets, and a limit of < 16% on 0.3R(J) planets in the EHJ period range. This is the first transit survey to place limits on the fraction of stars with planets as small as Neptune.

• 出版日期2009-4-10