A hot Jupiter orbiting a 2-million-year-old solar-mass T Tauri star

Abstract

Hot Jupiters are giant Jupiter-like exoplanets that orbit their host stars 100 times more closely than Jupiter orbits the Sun. These planets presumably form in the outer part of the primordial disk from which both the central star and surrounding planets are born, then migrate inwards and yet avoid falling into their host star. It is, however, unclear whether this occurs early in the lives of hot Jupiters, when they are still embedded within protoplanetary disks, or later, once multiple planets are formed and interact. Although numerous hot Jupiters have been detected around mature Sun-like stars, their existence has not yet been firmly demonstrated for young stars, whose magnetic activity is so intense that it overshadows the radial velocity signal that close-in giant planets can induce. Here we report that the radial velocities of the young star V830 Tau exhibit a sine wave of period 4.93 days and semi-amplitude 75 metres per second, detected with a false-alarm probability of less than 0.03 per cent, after filtering out the magnetic activity plaguing the spectra. We find that this signal is unrelated to the 2.741-day rotation period of V830 Tau and we attribute it to the presence of a planet of mass 0.77 times that of Jupiter, orbiting at a distance of 0.057 astronomical units from the host star. Our result demonstrates that hot Jupiters can migrate inwards in less than two million years, probably as a result of planet–disk interactions.

Variable Radio Emission From the Young Stellar Host of a Hot Jupiter

“…We plot in Figure 3, the detected flux density as a function of stellar rotational phase, using the ephemeris from Donati et al (2016). There is no clear trend in these sparse data with rotational phase.…”

“…The recent discovery of a hot Jupiter companion to V830 Tau has raised the possibility of study of an exoplanet associated with a young, active system (Donati et al 2015(Donati et al , 2016. V830 Tau is a non-accreting solar-mass T Tauri star located at 150 pc (Torres et al 2009).…”

Rocky Planet Formation: Quick and Neat

“…Several recent studies identify massive planets orbiting several pre-main sequence stars (e.g., Mann et al 2016;Gaidos et al 2016;David et al 2016;Donati et al 2016;Johns-Krull et al 2016b,a). Identifying Earth-mass planets orbiting young stars would constrain the timescale of terrestrial planet formation relative to the production of debris.…”

A Transient Transit Signature Associated with the Young Star RIK-210

“…David et al (2016b) pointed out that K2-33 b orbiting slightly interior to the corotation radius, with for the candidate ∼11-12M Jup planet around the T Tauri star CI Tau. Lastly, the planet V830 Tau b has a period ratio of » P P 1.8 orb rot (Donati et al 2016). …”