Evidence for Centrifugal Breakout around the Young M Dwarf TIC 234284556. (arXiv:2107.05649v2 [astro-ph.SR] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Palumbo_E/0/1/0/all/0/1">Elsa K. Palumbo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Montet_B/0/1/0/all/0/1">Benjamin T. Montet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Feinstein_A/0/1/0/all/0/1">Adina D. Feinstein</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bouma_L/0/1/0/all/0/1">Luke G. Bouma</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hartman_J/0/1/0/all/0/1">Joel D. Hartman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hillenbrand_L/0/1/0/all/0/1">Lynne A. Hillenbrand</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gully_Santiago_M/0/1/0/all/0/1">Michael A. Gully-Santiago</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Banks_K/0/1/0/all/0/1">Kirsten A. Banks</a>
Magnetospheric clouds have been proposed as explanations for depth-varying
dips in the phased light curves of young, magnetically active stars such as
$sigma$ Ori E and RIK-210. However, the stellar theory that first predicted
magnetospheric clouds also anticipated an associated mass-loss mechanism known
as centrifugal breakout for which there has been limited empirical evidence. In
this paper, we present data from TESS, LCO, ASAS-SN, and Veloce on the 45 Myr
M3.5 star TIC 234284556, and propose that it is a candidate for the direct
detection of centrifugal breakout. In assessing this hypothesis, we examine the
sudden ($sim$1-day timescale) disappearance of a previously stable
($sim$1-month timescale) transit-like event. We also interpret the presence of
an anomalous brightening event that precedes the disappearance of the signal,
analyze rotational amplitudes and optical flaring as a proxy for magnetic
activity, and estimate the mass of gas and dust present immediately prior to
the potential breakout event. After demonstrating that our spectral and
photometric data support a magnetospheric clouds and centrifugal breakout model
and disfavor alternate scenarios, we discuss the possibility of a coronal mass
ejection (CME) or stellar wind origin of the corotating material and we
introduce a reionization mechanism as a potential explanation for more gradual
variations in eclipse parameters. Finally, after comparing TIC 234284556 with
previously identified “flux-dip” stars, we argue that TIC 234284556 may be an
archetypal representative of a whole class of young, magnetically active stars.
Magnetospheric clouds have been proposed as explanations for depth-varying
dips in the phased light curves of young, magnetically active stars such as
$sigma$ Ori E and RIK-210. However, the stellar theory that first predicted
magnetospheric clouds also anticipated an associated mass-loss mechanism known
as centrifugal breakout for which there has been limited empirical evidence. In
this paper, we present data from TESS, LCO, ASAS-SN, and Veloce on the 45 Myr
M3.5 star TIC 234284556, and propose that it is a candidate for the direct
detection of centrifugal breakout. In assessing this hypothesis, we examine the
sudden ($sim$1-day timescale) disappearance of a previously stable
($sim$1-month timescale) transit-like event. We also interpret the presence of
an anomalous brightening event that precedes the disappearance of the signal,
analyze rotational amplitudes and optical flaring as a proxy for magnetic
activity, and estimate the mass of gas and dust present immediately prior to
the potential breakout event. After demonstrating that our spectral and
photometric data support a magnetospheric clouds and centrifugal breakout model
and disfavor alternate scenarios, we discuss the possibility of a coronal mass
ejection (CME) or stellar wind origin of the corotating material and we
introduce a reionization mechanism as a potential explanation for more gradual
variations in eclipse parameters. Finally, after comparing TIC 234284556 with
previously identified “flux-dip” stars, we argue that TIC 234284556 may be an
archetypal representative of a whole class of young, magnetically active stars.
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