Revisiting the HIP 41378 System with K2 and Spitzer

Journal Article · Wed May 01 04:00:00 EDT 2019 · Astronomical Journal (Online)

DOI:https://doi.org/10.3847/1538-3881/AB100C· OSTI ID:22897360

Berardo, David; Crossfield, Ian J. M. ^[1]; Werner, Michael; Gorjian, Varoujan; Morales, Farisa ^[2]; Petigura, Erik; Fulton, Benjamin J. ^[3]; Christiansen, Jessie; Ciardi, David R.; Hardegree-Ullman, Kevin ^[4]; Dressing, Courtney ^[5]; Greene, Thomas P. ^[6]; Kane, Stephen R. ^[7]; Livingston, John ^[8]

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1. Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
2. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
3. 1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)
4. NASA Exoplanet Science Institute, California Institute of Technology, M/S 100-22, 770 S. Wilson Avenue, Pasadena, CA (United States)
5. Astronomy Department, University of California, Berkeley, CA 94720 (United States)
6. NASA Ames Research Center, Space Science and Astrobiology Division, MS 245-6, Moffett Field, CA 94035 (United States)
7. University of California Riverside, Department of Earth Sciences, Riverside, CA 92521 (United States)
8. Department of Astronomy, University of Tokyo, 7-3-1 Hongo, Bunkyo-ky, Tokyo 113-0033 (Japan)

We present new observations of the multiplanet system HIP 41378, a bright star (V = 8.9, K {sub s} = 7.7) with five known transiting planets. Previous K2 observations showed multiple transits of two Neptune-sized bodies and single transits of three larger planets (R {sub P} = 0.33R {sub J}, 0.47R {sub J}, 0.88R {sub J}). K2 recently observed the system again in Campaign 18 (C18). We observe one new transit each of two of the larger planets d/f, giving maximal orbital periods of 1114/1084 days, as well as integer divisions of these values down to a lower limit of about 50 days. We use all available photometry to determine the eccentricity distributions of HIP 41378 d and f, finding that periods ≲300 days require non-zero eccentricity. We check for overlapping orbits of planets d and f to constrain their mutual periods, finding that short periods (P < 300 days) for planet f are disfavored. We also observe transits of planets b and c with Spitzer/Infrared Array Camera (IRAC), which we combine with the K2 observations to search for transit timing variations (TTVs). We find a linear ephemeris for planet b, but see a significant TTV signal for planet c. The ability to recover the two smaller planets with Spitzer shows that this fascinating system will continue to be detectable with Spitzer, CHEOPS, TESS, and other observatories, allowing us to precisely determine the periods of d and f, characterize the TTVs of planet c, recover the transits of planet e, and further enhance our view of this remarkable dynamical laboratory.

• OSTI ID: 22897360
• Journal Information: Astronomical Journal (Online), Journal Name: Astronomical Journal (Online) Journal Issue: 5 Vol. 157; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
DETECTION
DISTRIBUTION
NEPTUNE PLANET
ORBITS
PHOTOMETRY
SATELLITES
STARS