Constraining the period of the ringed secondary companion to the young star J1407 with photographic plates

¹ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, the Netherlands
e-mail: mentel@strw.leidenuniv.nl
² Department of Physics, Philipps-Universität Marburg, Renthof 5, 35032 Marburg, Germany
³ Department of Physics & Astronomy, University of Rochester, 500 Wilson Blvd., Rochester, NY 14627, USA
⁴ Chinese Academy of Sciences, 52 Sanlihe Road, Xicheng District, 100864 Beijing, PR China
⁵ Faculty of Electrical Engineering, Czech Technical University, Zikova 1903/4, 166 36 Prague, Czech Republic
⁶ Kazan Federal University, 18 Kremlyovskaya Street, 420008 Kazan, Russian Federation
⁷ Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
⁸ Harvard-Smithsonian Center for Astrophysics, 60 Garden St, Cambridge, MA 02138, USA
⁹ Jet Propulsion Laboratory, California Institute of Technology, M/S 321-100, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
¹⁰ Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Campus Box 3255, Chapel Hill, NC 27599, USA
¹¹ American Association of Variable Star Observers (AAVSO), 49 Bay State Rd., Cambridge, MA 02138, USA
¹² Center for Backyard Astrophysics (Antwerp), American Association of Variable Star Observers (AAVSO), Vereniging Voor Sterrenkunde (VVS), ROAD Observatory, Oude Bleken 12, 2400 Mol, Belgium
¹³ Perth Exoplanet Survey Telescope, Perth, Australia
¹⁴ Department of Physics and Astronomy, Vanderbilt University, 6301 Stevenson Center, Nashville, TN 37235, USA
¹⁵ South African Astronomical Observatory, PO Box 9, Observatory 7935, South Africa

Received: 2 August 2018
Accepted: 4 September 2018

Abstract

Context. The 16 Myr old star 1SWASP J140747.93-394542.6 (V1400 Cen) underwent a series of complex eclipses in May 2007, interpreted as the transit of a giant Hill sphere filling debris ring system around a secondary companion, J1407b. No other eclipses have since been detected, although other measurements have constrained but not uniquely determined the orbital period of J1407b. Finding another eclipse towards J1407 will help determine the orbital period of the system, the geometry of the proposed ring system and enable planning of further observations to characterize the material within these putative rings.

Aims. We carry out a search for other eclipses in photometric data of J1407 with the aim of constraining the orbital period of J1407b.

Methods. We present photometry from archival photographic plates from the Harvard DASCH survey, and Bamberg and Sonneberg Observatories, in order to place additional constraints on the orbital period of J1407b by searching for other dimming and eclipse events. Using a visual inspection of all 387 plates and a period-folding algorithm we performed a search for other eclipses in these data sets.

Results. We find no other deep eclipses in the data spanning from 1890 to 1990, nor in recent time-series photometry from 2012–2018.

Conclusions. We rule out a large fraction of putative orbital periods for J1407b from 5 to 20 yr. These limits are still marginally consistent with a large Hill sphere filling ring system surrounding a brown dwarf companion in a bound elliptical orbit about J1407. Issues with the stability of any rings combined with the lack of detection of another eclipse, suggests that J1407b may not be bound to J1407.