---
title: "Tabby's Star"
chunk: 2/5
source: "https://en.wikipedia.org/wiki/Tabby's_Star"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:16:04.645795+00:00"
instance: "kb-cron"
---

On 20 May 2017, Boyajian and her colleagues reported, via The Astronomer's Telegram, on an ongoing dimming event (named "Elsie") which possibly began on 14 May 2017. It was detected by the Las Cumbres Observatory Global Telescope Network, specifically by its telescope in Maui (LCO Maui). This was verified by the Fairborn Observatory (part of the N2K Consortium) in Southern Arizona (and later by LCO Canary Islands). Further optical and infrared spectroscopy and photometry were urgently requested, given the short duration of these events, which may be measured in days or weeks. Observations from multiple observers globally were coordinated, including polarimetry. Furthermore, the independent SETI projects Breakthrough Listen and Near-InfraRed Optical SETI (NIROSETI), both at Lick Observatory, continue to monitor the star. By the end of the three-day dimming event, a dozen observatories had taken spectra, with some astronomers having dropped their own projects to provide telescope time and resources. More generally the astronomical community was described as having gone "mildly bananas" over the opportunity to collect data in real-time on the unique star. The 2% dip event was named "Elsie" (a homophone of "LC", in reference to Las Cumbres and light curve).
Initial spectra with FRODOSpec at the two-meter Liverpool Telescope showed no changes visible between a reference spectrum and this dip. Several observatories, however, including the twin Keck telescopes (HIRES) and numerous citizen science observatories, acquired spectra of the star, showing a dimming that had a complex shape, and initially had a pattern similar to the one at 759.75 days from the Kepler event 2, epoch 2 data. Observations were taken across the electromagnetic spectrum.
Evidence of a second dimming event (named "Celeste") was observed on 13–14 June 2017, which possibly began 11 June, by amateur astronomer Bruce L. Gary. While the light curve on 14–15 June indicated a possible recovery from the dimming event, the dimming continued to increase afterwards, and on 16 June, Boyajian wrote that the event was approaching a 2% dip in brightness.
A third prominent 1% dimming event (named "Skara Brae") was detected beginning 2 August 2017, and which recovered by 17 August.
A fourth prominent dimming event (named "Angkor") began 5 September 2017, and is, as of 16 September 2017, between 2.3% and 3% dimming event, making it the "deepest dip this year".
Another dimming event, amounting to a 0.3% dip, began around 21 September 2017, and completely recovered by 4 October 2017.
On 10 October 2017, an increasing brightening, lasting about two weeks, of the starlight from KIC 8462852 (Tabby's Star) was noted by Bruce L. Gary of the Hereford Arizona Observatory and Boyajian. A possible explanation, involving a transiting brown dwarf in a 1,600-day eccentric orbit near KIC 8462852, a "drop feature" in dimness and predicted intervals of brightening, to account for the unusual fluctuating starlight events of KIC 8462852, has been proposed.
On about 20 November 2017, a fifth prominent dimming event began and had deepened to a depth of 0.44%; as of 16 December 2017, the event recovered, leveled off at dip bottom for 11 days, faded again, to a current total dimming depth of 1.25%, and was recovering again.
Dimming and brightening events of the star continue to be monitored; related light curves are updated and released frequently.

=== 2018 light fluctuations ===
The star was too close to the Sun's position in the sky from late December 2017 to mid February 2018 to be seen. Observations resumed in late February. A new series of dips began on 16 March 2018. By 18 March 2018, the star was down in brightness by more than 1% in g-band, according to Bruce L. Gary, and about 5% in r-band, making it the deepest dip observed since the Kepler Mission in 2013, according to Tabetha S. Boyajian. A second even deeper dip with a depth of >5% started on 24 March 2018, as confirmed by AAVSO observer John Hall. As of 27 March 2018, that second dip was recovering.

=== 2019 light fluctuations ===
The 2019 observing season began in mid-March, when the star reappeared after its yearly conjunction with the Sun.
The ground based observation campaign was supplemented by the Transiting Exoplanet Survey Satellite (TESS), which observed the star every 2 minutes between 18 July – 11 September 2019. It observed a 1.4% dip in brightness between 3–4 September 2019.
Between October 2019 and December 2019, at least seven separate dips were observed, the deepest of which had a depth of 2%. By the end of the observing season in early January 2020, the star had once again recovered in brightness. The total combined depth of the dips in 2019 was 11%, comparable to that seen in 2011 and 2013, but spread over a long time interval. This cluster of dips is roughly centered on the 17 October 2019 date predicted by Sacco et al. for a reappearance, given a 1,574-day (4.31-year) period, of orbiting material comprising the original "D800" dip.