The Rapid Outbursting Star GM Cep: An EX-or in Tr 37?

Abstract

We present optical, IR and millimeter observations of the solar-type star 13-277, also known as GM Cep, in the 4 Myr-old cluster Tr 37. GM Cep experiences rapid magnitude variations of more than 2 mag at optical wavelengths. We explore the causes of the variability, which seem to be dominated by strong increases in the accretion, being similar to EX-or episodes. The star shows high, variable accretion rates (up to ~10${}^{-6}$ Msun/yr), signs of powerful winds, and it is a very fast rotator (Vsini~43 km/s). Its strong mid-IR excesses reveal a very flared disk and/or a remnant envelope, most likely out of hydrostatic equilibrium. The 1.3 millimeter fluxes suggest a relatively massive disk (Mdisk~0.1 Msun). Nevertheless, the millimeter mass is not enough to sustain increased accretion episodes over large timescales, unless the mass is underestimated due to significant grain growth. We finally explore the possibility of GM Cep having a binary companion, which could trigger disk instabilities producing the enhanced accretion episodes.

arXiv comment43 pages, including 10 figures, ApJ in press

References in corpus (22)

• The USNO-B Catalog
• An atomic and molecular database for analysis of submillimetre line observations
• Passive irradiated circumstellar disks with an inner hole
• Accretion in Brown Dwarfs: an Infrared View
• Lucky Imaging: High Angular Resolution Imaging in the Visible from the Ground
• Large dust particles in disks around T Tauri stars
• H2 and CO emission from disks around TTauri and HerbigAe pre-main-sequence stars and from debris disks around young stars: warm and cold circumstellar gas
• High-Resolution Spectroscopy in Tr37: Gas Accretion Evolution in Evolved Dusty Disks
• Massive planets in FU Orionis discs: implications for thermal instability models
• High-Resolution Spectroscopy of FUors
• Binarity as a key factor in protoplanetary disk evolution: Spitzer disk census of the eta Chamaeleontis cluster
• Non-axisymmetric accretion on the classical TTS RW Aur A
• The outburst of the eruptive young star OO Serpentis between 1995 and 2006
• Low Mass Companions to T~Tauri Stars: a Mechanism for Rapid-rise FU~Orionis Outbursts
• Diffraction-limited CCD imaging with faint reference stars
• FU Orionis - The MIDI/VLTI Perspective
• Optical and infrared properties of V1647 Orionis during the 2003-2006 outburst. II. Temporal evolution of the eruptive source
• The infrared properties of the new outburst star IRAS 05436-0007 in quiescent phase
• The Disappearing Act of KH 15D: Photometric Results from 1995 to 2004
• Long-term infrared variability of the UX Ori-type star SV Cep
• Library of high and mid-resolution spectra in the CaII H & K, H{alpha}, H{beta}, NaI D{1}, D{2}, and HeI D{3} line regions of F, G, K and M field stars
• Periodic variations in the colours of the classical T Tauri star RW Aur A

Cited by in corpus (22)

• The AstraLux Large M-dwarf Multiplicity Survey
• Episodic formation of cometary material in the outburst of a solar-like young star
• Accretion in Evolved and Transitional Disks in Cep OB2: Looking for the Origin of the Inner Holes
• Fu Ori outbursts and the planet-disc mass exchange
• Near Infrared Spectroscopic Monitoring of EXor variables: First Results
• On the nature of the EXor accretion events: an unfrequent manifestation of a common phenomenology ?
• Highly Variable Extinction and Accretion in the Jet-driving Class I Type Young Star PTF 10nvg (V2492 Cyg, IRAS 20496+4354)
• Dawes Review. The tidal downsizing hypothesis of planet formation
• Dust properties and disk structure of evolved protoplanetary disks in Cep OB2: Grain growth, settling, gas and dust mass, and inside-out evolution
• Time-resolved photometry of the young dipper RX J1604.3-2130A: Unveiling the structure and mass transport through the innermost disk
• The 2014-2017 outburst of the young star ASASSN-13db: A time-resolved picture of a very low-mass star between EXors and FUors
• A "Rosetta Stone" for protoplanetary disks: The synergy of multi-wavelength observations
• Dynamics during outburst: VLTI observations of the young eruptive star V1647 Ori during its 2003-2006 outburst
• Optical photometry of GM Cep: evidence for UXor type of variability
• IRAM and Gaia views of multi-episodic star formation in IC1396A: The origin and dynamics of the Class 0 protostar at the edge of an HII region
• Long-Term Light Curve of Highly-Variable Protostellar Star GM Cep
• A Possible Detection of Occultation by a Proto-planetary Clump in GM Cephei
• Pre-Main Sequence variables in the VMR-D : identification of T Tauri-like accreting protostars through Spitzer-IRAC variability
• Diagnosing the Clumpy Protoplanetary Disk of the UXor Type Young Star GM Cephei
• The unusual photometric variability of the PMS star GM Cep
• Towards a better classification of unclear eruptive variables: the cases of V2492 Cyg, V350 Cep, and ASASSN-15qi
• A long-lasting quiescence phase of the eruptive variable V1118 Ori