First Millimeter Flares Detected from ϵ Eridani with the Atacama Large Millimeter/submillimeter Array

Burton, Kiana; MacGregor, Meredith A.; Osten, Rachel A.

doi:10.3847/2041-8213/ac9973

Cited by 4 publications

(3 citation statements)

References 47 publications

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“…= 0 4 and Δdecl. = −0 7, consistent with the best-fit from analysis of T3) to the visibilities in all eight tracks, binned at either 30 s, 60 s, or 180 s resolution, an approach consistent with the studies of MacGregor et al (2020) and Burton et al (2022). These represent time-binning by factors of 1-6 (for T1 and T3); 2-12 (for T2); and 6-36 (for T4-T8).…”

Section: Per-scan Variabilitysupporting

confidence: 75%

“…The details of HD 283572ʼs millimeter emission appear different than those reported for main-sequence flares from single stars, such as those of AU Mic, Proxima Centauri, ò Eri, and the Sun (Krucker et al 2013;MacGregor et al 2018MacGregor et al , 2020Burton et al 2022, with millimeter luminosity densities of 10 13 -3×10 14 erg s −1 Hz −1 , 10 s of seconds flare timescales, and for the Sun and ò Eri, positive/flat spectral indices). HD 283572ʼs flare luminosity density is a factor of ∼1000 × higher than the brightest of those, ò Eri (based on F1/F1A), persisted over 9 hr (∼1000 × longer) and had a negative spectral index throughout.…”

Section: Flares From Single Starsmentioning

confidence: 65%

“…At millimeter wavelengths, stellar variability campaigns have mostly targeted nearby main sequence M-type stars, such as Proxima Centauri and AU Mic, finding extreme flaring events on timescales of 1-10 s (MacGregor et al 2020(MacGregor et al , 2021Howard et al 2022). A handful of millimeter flares have also been detected from the closest Sun-like star, ò Eridani (Burton et al 2022), and a range of other M-and K-type stars from millimeter survey telescopes (e.g., the South Pole Telescope and the Atacama Cosmology Telescope; see, e.g., Guns et al 2021;Naess et al 2021).…”

Section: Introductionmentioning

confidence: 99%

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SMA Detection of an Extreme Millimeter Flare from the Young Class III Star HD 283572

Lovell,

Keating,

Wilner

et al. 2024

ApJL

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We present evidence of variable 1.3 mm emission from the 1 to 3 Myr, spectral-type G2–G5 class III young stellar object (YSO), HD 283572. HD 283572 was observed on eight dates with the Submillimeter Array between 2021 December and 2023 May, with a total on-source time of 10.2 hr, probing a range of timescales down to 5.2 s. Averaging all data obtained on 2022 January 17 shows a 4.4 mJy (8.8σ) point source detection with a negative spectral index (α = −2.7 ± 1.2), with peak emission rising to 13.8 mJy in one 3 minute span, and 25 mJy in one 29.7 s integration (L ν = 4.7 × 1017 erg s−1 Hz−1). Combining our data for the other seven dates shows no detection, with an rms noise of 0.24 mJy beam−1. The stochastic millimeter enhancements on time frames of seconds–minutes–hours with negative spectral indices are most plausibly explained by synchrotron or gyrosynchrotron radiation from stellar activity. HD 283572's 1.3 mm lightcurve has similarities with variable binaries, suggesting HD 283572's activity may have been triggered by interactions with an as-yet undetected companion. We additionally identify variability of HD 283572 at 10 cm, from VLASS data. This study highlights the challenges of interpreting faint millimeter emission from evolved YSOs that may host tenuous disks, and suggests that a more detailed temporal analysis of spatially unresolved data is generally warranted. The variability of class III stars may open up new ground for understanding the physics of flares in the context of terrestrial planet formation.

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Section: Per-scan Variabilitysupporting

confidence: 75%

Section: Flares From Single Starsmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

SMA Detection of an Extreme Millimeter Flare from the Young Class III Star HD 283572

Lovell,

Keating,

Wilner

et al. 2024

ApJL

Self Cite

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Understanding the radio emission from ϵ Eridani

Rodríguez,

Lizano,

Cantó

et al. 2023

A&A

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Some solar-type stars are known to present faint, time-variable radio continuum emission whose nature is not clearly established. We report on Jansky Very Large Array observations of the nearby star ϵ Eridani at 10.0 and 33.0 GHz. We find that this star has flux density variations on scales down to days, hours, and minutes. On 2020 April 15 it exhibited a radio pulse at 10.0 GHz with a total duration of about 20 min and a peak four times larger than the plateau of 40 μJy present in that epoch. We were able to model the time behavior of this radio pulse in terms of the radiation from shocks ramming into the stellar wind. Such shocks can be produced by the wind interaction of violently expanding gas heated suddenly by energetic electrons from a stellar flare, similar to the observed solar flares. Because of the large temperature needed in the working surface to produce the observed emission, this has to be nonthermal. It could be gyrosynchrotron or synchrotron emission. Unfortunately, the spectral index or polarization measurements from the radio pulse do not have a high enough signal-to-noise ratio to allow us to determine its nature.

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SPRITEly: Time-domain Millimeter Interferometry at the Owens Valley Radio Observatory

Yurk,

Ravi,

Hodges

et al. 2024

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Though the time-domain millimeter sky is yet to be well characterized, the scarcity of millimeter observing resources in the world at present hampers progress toward it. In efforts to bolster the exploration of millimeter transients, we present the Stokes Polarization Radio Interferometer for Time-Domain Experiments (SPRITEly). Located at the Owens Valley Radio Observatory, SPRITEly is currently deployed as a two-element short-baseline 90 GHz interferometer uniquely focused on monitoring bright variable millimeter-continuum sources. We leverage two existing 10.4 m antennas and their existing receiver systems to begin, but we make significant upgrades to the back-end system during the commissioning process. With the ability to achieve rms noise of a few mJy, we plan to monitor known variable sources along with new nearby transients detected from optical surveys at high cadence, with the goal of producing well-sampled light curves. Interpreting these data in conjunction with multiwavelength observations stands to provide insight into the physical properties of the sources that produce transient millimeter emission. We present commissioning and early-science observations that demonstrate the performance of the instrument, including observations of the flaring BL Lac object S2 0109+22 and a periastron passage of the binary T Tauri system DQ Tau.

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First Millimeter Flares Detected from ϵ Eridani with the Atacama Large Millimeter/submillimeter Array

Cited by 4 publications

References 47 publications

SMA Detection of an Extreme Millimeter Flare from the Young Class III Star HD 283572

SMA Detection of an Extreme Millimeter Flare from the Young Class III Star HD 283572

Understanding the radio emission from ϵ Eridani

SPRITEly: Time-domain Millimeter Interferometry at the Owens Valley Radio Observatory

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