Kepler photometry has revealed two unusual transiting companions: one orbiting an early A-star and the other orbiting a late B-star. In both cases, the occultation of the companion is deeper than the transit. The occultation and transit with follow-up optical spectroscopy reveal a 9400 K early A-star, KOI-74 (KIC 6889235), with a companion in a 5.2 day orbit with a radius of 0.08 R sun and a 10,000 K late B-star KOI-81 (KIC 8823868) that has a companion in a 24 day orbit with a radius of 0.2 R sun. We infer a temperature of 12,250 K for KOI-74b and 13,500 K for KOI-81b. We present 43 days of high duty cycle, 30 minute cadence photometry, with models demonstrating the intriguing properties of these objects, and speculate on their nature.
The Astrophysical Journal
- Pub Date:
- April 2010
- stars: individual: KOI-74 KIC 6889235 KOI-81 KIC 8823868;
- Astrophysics - Solar and Stellar Astrophysics
- 12 pages, 3 figures, submitted to ApJL (updated to correct KOI74 lightcurve)