Direct Imaging discovery of a second planet candidate around the possibly transiting planet host CVSO 30

Abstract

Context. Direct imaging has developed into a very successful technique for the detection of exoplanets in wide orbits, especially around young stars. Directly imaged planets can be both followed astrometrically on their orbits and observed spectroscopically and thus provide an essential tool for our understanding of the early solar system. Aims. We surveyed the 25 Ori association for direct-imaging companions. This association has an age of only few million years. Among other targets, we observed CVSO 30, which has recently been identified as the first T Tauri star found to host a transiting planet candidate. Methods. We report on photometric and spectroscopic high-contrast observations with the Very Large Telescope, the Keck telescopes, and the Calar Alto observatory. They reveal a directly imaged planet candidate close to the young M3 star CVSO 30. Results. The JHK-band photometry of the newly identified candidate is at better than 1 σ consistent with late-type giants, early-T and early-M dwarfs, and free-floating planets. Other hypotheses such as galaxies can be excluded at more than 3.5 σ. A lucky imaging z ′ photometric detection limit z ′ = 20.5 mag excludes early-M dwarfs and results in less than 10 M Jup for CVSO 30 c if bound. We present spectroscopic observations of the wide companion that imply that the only remaining explanation for the object is that it is the first very young (< 10 Myr) L -T-type planet bound to a star, meaning that it appears bluer than expected as a result of a decreasing cloud opacity at low effective temperatures. Only a planetary spectral model is consistent with the spectroscopy, and we deduce a best-fit mass of 4 -5 Jupiter masses (total range 0.6 -10.2 Jupiter masses). Conclusions. This means that CVSO 30 is the first system in which both a close-in and a wide planet candidate are found to have a common host star. The orbits of the two possible planets could not be more different: they have orbital periods of 10.76 hours and about 27000 years. The two orbits may have formed during a mutual catastrophic event of planet-planet scattering.

YETI follow-up observations of the T Tauri star CVSO30 with transit-like dips

“…As a result, we could confirm the detection of a transit-like signal within the light curve of CVSO 30, which was first found by van Eyken et al (2012). Schmidt et al (2016) discovered an additional wide companion planet candidate via direct imaging. CVSO 30, which is also known as PTFO 8-8695, is a weak-line T Tauri star with spectral type E-mail: richard.bischoff@uni-jena.de M3 (Briceño et al 2005), which showed initially brightness dips of ∼ 35 mmag every ∼ 10.8 h lasting about 100 min.…”

“…We used high-resolution direct imaging data with adaptive optics of CVSO 30 from the ESO archive to estimate an upper limit on the possible separation, if CVSO 30 consists of two equally bright stars. The target was observed with NACO at ESO's VLT on December 03 2012 in jitter mode, using a jitter-width of 4 arcsec, and the data were presented first in Schmidt et al (2016). According to the ESO ambient conditions database 4 the average DIMM seeing was 0.67 ± 0.03 arcsec and the average coherence time of the atmospheric fluctuations was 4.5 ± 0.2 ms during the Ks-band observations.…”

Evidence for planetary hypothesis for PTFO 8-8695 b with five-year optical/infrared monitoring observations

“…The same conclusion as for V830 Tau b (Donati et al 2016) and K2-33 b (Mann et al 2016) implies that the planet formation and orbital evolution would be generally completed within a few Myr. Recently, Schmidt et al (2016) reported on the dete ction of a putative second planet candidate CVSO 30 c (PTFO 8-8695 c) orbiting at 662 au. If their planet candidate and our identification of a transiting planet are both true, PTFO8-8695 is the first system where a close-in planet and a wide separation planet are found to be orbiting the same star.…”

PTFO 8-8695: Two Stars, Two Signals, No Planet

“…This point source was claimed to be a potential planetary-mass object(Schmidt et al 2016). Subsequent analysis of its colors showed that it is a background star (Lee & Chiang 2018).…”