Planet Hunters TESS IV: A massive, compact hierarchical triple star system TIC 470710327

Abstract

We report the discovery and analysis of a massive, compact, hierarchical triple system (TIC 470710327) initially identified by citizen scientists in data obtained by NASA's Transiting Exoplanet Survey Satellite (TESS). Spectroscopic follow-up observations obtained with the HERMES spectrograph, combined with eclipse timing variations (ETVs), confirm that the system is comprised of three OB stars, with a compact 1.10 d eclipsing binary and a non-eclipsing tertiary on a 52.04 d orbit. Dynamical modelling of the system (from radial velocity and ETVs) reveal a rare configuration wherein the tertiary star (O9.5-B0.5V; 14-17 M${}_{\odot }$) is more massive than the combined mass of the inner binary (10.9-13.2 M${}_{\odot }$). Given the high mass of the tertiary, we predict that this system will undergo multiple phases of mass transfer in the future, and likely end up as a double neutron star gravitational wave progenitor or an exotic Thorne-Zytkow object. Further observational characterisation of this system promises constraints on both formation scenarios of massive stars as well as their exotic evolutionary end-products.

arXiv commentAccepted for publication in MNRAS (11 pages, 8 figures)

References in corpus (75)

• Astropy: A Community Python Package for Astronomy
• The NumPy array: a structure for efficient numerical computation
• Gaia Data Release 2. Summary of the contents and survey properties
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The Gaia mission
• The Transiting Exoplanet Survey Satellite
• MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
• Binary interaction dominates the evolution of massive stars
• The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617
• Galaxy Zoo : Morphologies derived from visual inspection of galaxies from the Sloan Digital Sky Survey
• A statistical study of 233 pulsar proper motions
• Toward Understanding Massive Star Formation
• The WASP Project and the SuperWASP Cameras
• Gaia Early Data Release 3: The astrometric solution
• Mind your Ps and Qs: the Interrelation between Period (P) and Mass-ratio (Q) Distributions of Binary Stars
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)
• A new calibration of stellar parameters of Galactic O stars
• Common Envelope Evolution: Where we stand and how we can move forward
• A Universal Stellar Initial Mass Function? A Critical Look at Variations
• The Eccentric Kozai-Lidov Effect and Its Applications
• astroquery: An Astronomical Web-Querying Package in Python
• Galaxy Zoo 1 : Data Release of Morphological Classifications for nearly 900,000 galaxies
• Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection
• The rotation rates of massive stars: the role of binary interaction through tides, mass transfer and mergers
• The Second-Generation Guide Star Catalog: Description and Properties
• The VLT-FLAMES Tarantula Survey VIII. Multiplicity properties of the O-type star population
• HERMES: a high-resolution fibre-fed spectrograph for the Mercator telescope
• The Galactic O-Star Spectroscopic Survey. I. Classification System and Bright Northern Stars in the Blue-Violet at R~2500
• The incidence of stellar mergers and mass gainers among massive stars
• Binary black hole mergers from field triples: properties, rates and the impact of stellar evolution
• The Formation of Close Binary Systems by Dynamical Interactions and Orbital Decay
• The Eccentric Kozai Mechanism for a Test Particle
• Massive runaways and walkaway stars
• Long-Term Cycling of Kozai-Lidov Cycles: Extreme Eccentricities and Inclinations Excited by a Distant Eccentric Perturber
• The N2K Consortium. IV. New temperatures and metallicities for 100,000+ FGK dwarfs
• Collapse of a Molecular Cloud Core to Stellar Densities: The First Three-Dimensional Calculations
• A Comprehensive Study of the Kepler Triples via Eclipse Timing
• Gaia Early Data Release 3: Summary of the contents and survey properties
• The observed velocity distribution of young pulsars
• Circumbinary, not transitional: On the spiral arms, cavity, shadows, fast radial flows, streamers and horseshoe in the HD142527 disc
• Kepler Eclipsing Binary Stars. IV. Precise Eclipse Times for Close Binaries and Identification of Candidate Three-Body Systems
• An Updated Look at Binary Characteristics of Massive Stars in the Cygnus OB2 Association
• Eclipse Timing Variation Analyses of Eccentric Binaries with Close Tertiaries in the Kepler field
• Chaos in the Test Particle Eccentric Kozai-Lidov Mechanism
• Measuring the Recoverability of Close Binaries in Gaia DR2 with the Robo-AO Kepler Survey
• The Fate of Binaries in the Galactic Center: The Mundane and the Exotic
• The Multiplicity of Massive Stars: A High Angular Resolution Survey with the HST Fine Guidance Sensor
• Massive Star Formation
• Extreme orbital evolution from hierarchical secular coupling of two giant planets
• The observed velocity distribution of young pulsars II: analysis of complete PSR$\pi$
• Modeling disk fragmentation and multiplicity in massive star formation
• MONOS: Multiplicity Of Northern O-type Spectroscopic systems. I. Project description and spectral classifications and visual multiplicity of previously known objects
• Discovery of a Thorne-Zytkow object candidate in the Small Magellanic Cloud
• Multiple Stellar Evolution: a population synthesis algorithm to model the stellar, binary, and dynamical evolution of multiple-star systems
• Simulations of common envelope evolution in triple systems: Circumstellar case
• The young massive SMC cluster NGC 330 seen by MUSE II. Multiplicity properties of the massive-star population
• Denoising spectroscopic data by means of the improved Least-Squares Deconvolution method
• Massive stars reveal variations of the stellar initial mass function in the Milky Way stellar clusters
• Spiral arms and instability within the AFGL 4176 mm1 disc
• The evolution of triples with a Roche-lobe filling outer star
• Planet Hunters TESS II: Findings from the first two years of TESS
• Hubble Space Telescope NICMOS Imaging of W3 IRS 5: A Trapezium in the Making?
• EPIC 220204960: A Quadruple Star System Containing Two Strongly Interacting Eclipsing Binaries
• Constraining the Overcontact Phase in Massive Binary Evolution I. Mixing in V382 Cyg, VFTS 352, and OGLE SMC-SC10 108086
• Stars stripped in binaries -- the living gravitational wave sources
• Detecting Unresolved Binaries in TESS Data with Speckle Imaging
• A search for tight hierarchical triple systems amongst the eclipsing binaries in the CoRoT fields
• BG Ind: the nearest doubly eclipsing, compact hierarchical quadruple system
• A study of light travel time effect in short-period MOA eclipsing binaries via eclipse timing
• Mergers of Equal-Mass Binaries with Compact Object Companions from Mass Transfer in Triple Star Systems
• A Triple Origin for Twin Blue Stragglers in Close Binaries
• Variability survey of brightest stars in selected OB associations
• KIC 2856960: the impossible triple star
• Tying the geometrical traits of massive young stellar objects and their discs to a potential evolutionary sequence using infrared observations

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• The TESS Triple-9 Catalog II: a new set of 999 uniformly-vetted exoplanet candidates
• Hypercritical accretion during common envelopes in triples leading to binary black holes in the pair-instability-supernova mass gap
• Detached Eclipsing Binaries in Compact Hierarchical Triples: Triple-lined systems BD+44 2258 and KIC 06525196
• Prompt stellar and binary black hole mergers in tight triples: Insights from chemically homogeneous evolution
• Spectroscopy of Eclipsing Compact Hierarchical Triples I
• Extreme resonant eccentricity excitation of stars around merging black-hole binary
• Detailed Simulations of Massive Hierarchical Triple Star Systems - Exploring the impact of the stellar physics on the evolutionary pathways of massive hierarchical triple systems
• Thorne-Żytkow Objects
• Population synthesis of Thorne-Żytkow objects: Rejuvenated donors and unexplored progenitors in the common envelope formation channel
• Discovery of a compact hierarchical triple main-sequence star system while searching for binary stars with compact objects
• Formation of massive multiple-star systems: early migration and mergers
• The Visual Survey Group: A Decade of Hunting Exoplanets and Unusual Stellar Events with Space-Based Telescopes