A search for transiting companions in the J1407 (V1400 Cen) system

Abstract

In 2007, the young star 1SWASP J140747.93-394542.6 (V1400 Cen) underwent a complex series of deep eclipses over 56 days. This was attributed to the transit of a ring system filling a large fraction of the Hill sphere of an unseen substellar companion. Subsequent photometric monitoring has not found any other deep transits from this candidate ring system, but if there are more substellar companions and they are coplanar with the potential ring system, there is a chance that they will transit the star as well. This young star is active and the light curves show a 5% modulation in amplitude with a dominant rotation period of 3.2 days due to star spots rotating in and out of view. We model and remove the rotational modulation of the J1407 light curve and search for additional transit signatures of substellar companions orbiting around J1407. We combine the photometry of J1407 from several observatories, spanning a 19 year baseline. We remove the rotational modulation by modeling the variability as a periodic signal, whose periodicity changes slowly with time over several years due to the activity cycle of the star. A Transit Least Squares (TLS) analysis searches for any periodic transiting signals within the cleaned light curve. We identify an activity cycle of J1407 with a period of 5.4 years. A Transit Least Squares search does not find any plausible periodic eclipses in the light curve, from 1.2% amplitude at 5 days up to 1.9% at 20 days. This sensitivity is confirmed by injecting artificial transits into the light curve and determining the recovery fraction as a function of transit depth and orbital period. J1407 is confirmed as a young active star with an activity cycle consistent with a rapidly rotating solar mass star. With the rotational modulation removed, the TLS analysis rules out transiting companions with radii larger than about 1 Jupiter.

arXiv comment8 pages, 9 figures, 3 tables, accepted for publication in Astronomy & Astrophysics. Reduced data and reduction scripts on github at https://github.com/StanBarmentloo/J1407_transit_search_activity

References in corpus (30)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The Transiting Exoplanet Survey Satellite
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• The SIMBAD astronomical database
• The Solar Cycle
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• batman: BAsic Transit Model cAlculatioN in Python
• The Limiting Effects of Dust in Brown Dwarf Model Atmospheres
• A box-fitting algorithm in the search for periodic transits
• The Kilodegree Extremely Little Telescope (KELT): A Small Robotic Telescope for Large-Area Synoptic Surveys
• A ring system detected around the Centaur (10199) Chariklo
• Transit Least Squares: Optimized transit detection algorithm to search for periodic transits of small planets
• eleanor: An open-source tool for extracting light curves from the TESS Full-Frame Images
• The KELT-South Telescope
• Statistical Properties of Brown Dwarf Companions: Implications for Different Formation Mechanisms
• Planetary Construction Zones in Occultation: Discovery of an Extrasolar Ring System Transiting a Young Sun-like Star and Future Prospects for Detecting Eclipses by Circumsecondary and Circumplanetary Disks
• Searching the Entirety of Kepler Data. II. Occurrence Rate Estimates for FGK Stars
• Modeling giant extrasolar ring systems in eclipse and the case of J1407b: sculpting by exomoons?
• Mass and period limits on the ringed companion transiting the young star J1407
• An Extreme Analogue of $\epsilon$ Aurigae: An M-giant Eclipsed Every 69 Years by a Large Opaque Disk Surrounding a Small Hot Source
• Planetary Rings
• Discovery of an unusual bright eclipsing binary with the longest known period: TYC 2505-672-1 / MASTER OT J095310.04+335352.8
• Constraints on the size and dynamics of the J1407b ring system
• Extended Transiting Disks and Rings Around Planets and Brown Dwarfs: Theoretical Constraints
• Constraining the period of the ringed secondary companion to the young star J1407 with photographic plates
• Shapes of stellar activity cycles
• A search for transiting planets in the $\beta$ Pictoris system
• Rings in the Solar System: a short review

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