---
title: "Tabby's Star"
chunk: 5/5
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"
---

=== Intrinsic luminosity variations ===
The reddening observed during the deep dimming events of Tabby's Star is consistent with cooling of its photosphere. It does not require obscuration by dust. Such cooling could be produced by a decreased efficiency of heat transport caused e.g. by decreased effectiveness of convection due to the star's strong differential rotation, or by changes in its modes of heat transport if it is near the transition between radiative and convective heat transport. The "missing" heat flux is stored as a small increase of internal and potential energy.
The possible location of this early F star near the boundary between radiative and convective transport seems to be supported by the finding that the star's observed brightness variations appear to fit the "avalanche statistics" known to occur in a system close to a phase-transition. "Avalanche statistics" with a self-similar or power-law spectrum are a universal property of complex dynamical systems operating close to a phase transition or bifurcation point between two different types of dynamical behavior. Such close-to-critical systems are often observed to exhibit behavior that is intermediate between "order" and "chaos". Three other stars in the Kepler Input Catalog likewise exhibit similar "avalanche statistics" in their brightness variations, and all three are known to be magnetically active. It has been conjectured that stellar magnetism may be involved in Tabby's Star.

=== An artificial megastructure ===

Some astronomers have speculated that the objects eclipsing Tabby's Star could be parts of a megastructure made by an alien civilization, such as a Dyson swarm, a hypothetical structure that an advanced civilization might build around a star to intercept some of its light for their energy needs. According to Steinn Sigurðsson, the megastructure hypothesis is implausible and disfavored by Occam's razor and fails to sufficiently explain the dimming. He says that it remains a valid subject for scientific investigation, however, because it is a falsifiable hypothesis. Due to extensive media coverage on this matter, Tabby's Star has been compared by Kepler's Steve Howell to KIC 4150611, a star with an odd light curve that was shown, after years of research, to be a part of a five-star system. The likelihood of extraterrestrial intelligence being the cause of the dimming is purely speculative; however, the star remains an outstanding SETI target because natural explanations have yet to fully explain the dimming phenomenon. The latest results have ruled out explanations involving only opaque objects such as stars, planets, swarms of asteroids, or alien megastructures.

=== Exomoons ===
Two papers published in summer 2019 offered plausible scientific scenarios involving large moons being stripped from their planets. Numeric simulations were performed of the migration of gas giant planets, and their large gaseous moons, during the first few hundred million years after the formation of the planetary system. In approximately 50% of the cases, the results produce a scenario where the moon is freed from its parent planet and its orbit evolves to produce a light curve similar to that of Tabby's Star.

== Follow-up studies ==
As of 2015, numerous optical telescopes were monitoring Tabby's Star in anticipation of another multi-day dimming event, with planned follow-up observations of a dimming event using large telescopes equipped with spectrographs to determine if the eclipsing mass is a solid object, or composed of dust or gas. Additional follow-up observations may involve the ground-based Green Bank Telescope, the Very Large Array Radio Telescope, and future orbital telescopes dedicated to exoplanetology such as the Nancy Grace Roman Space Telescope, TESS, and PLATO.
In 2016, a Kickstarter fund-raising campaign was led by Tabetha Boyajian, the lead author of the initial study on the star's anomalous light curve. The project proposed to use the Las Cumbres Observatory Global Telescope Network for continuous monitoring of the star. The campaign raised over US$100,000, enough for one year of telescope time. Furthermore, as of 2016, more than fifty amateur astronomers working under the aegis of the American Association of Variable Star Observers were providing effectively full coverage since AAVSO's alert about the star in October 2015, namely a nearly continuous photometric record. In a study published in January 2018, Boyajian et al. reported that whatever is blocking Tabby's Star filters different wavelengths of light differently, so it cannot be an opaque object. They concluded that it is most likely space dust.
In December 2018, a search for laser light emissions from Tabby's Star was carried out using the Automated Planet Finder (APF), which is sensitive enough to detect a 24 MW laser at this distance. Although a number of candidates were identified, further analysis showed that they are coming from the Earth and not from the star.

=== SETI results ===
In October 2015, the SETI Institute used the Allen Telescope Array to look for radio emissions from possible intelligent extraterrestrial life in the vicinity of the star. After an initial two-week survey, the SETI Institute reported that it found no evidence of technology-related radio signals from the star system. No narrowband radio signals were found at a level of 180–300 Jy in a 1 Hz channel, or medium-band signals above 10 Jy in a 100 kHz channel.
In 2016, the VERITAS gamma-ray observatory was used to search for ultra-fast optical transients from astronomical objects, with astronomers developing an efficient method sensitive to nanosecond pulses with fluxes as low as about one photon per square meter. This technique was applied on archival observations of Tabby's Star from 2009 to 2015, but no emissions were detected.
In May 2017, a related search, based on laser light emissions, was reported, with no evidence found for technology-related signals from Tabby's Star.
In September 2017, some SETI@Home workunits were created based on a previous RF survey of the region around this star. This was coupled with a doubling in the size of SETI@Home workunits, so the workunits related to this region will probably be the first workunits to have less issues with quantization noise.

=== EPIC 204278916 ===

A star called EPIC 204278916, as well as some other young stellar objects, have been observed to exhibit dips with some similarities to those observed in Tabby's Star. They differ in several respects, however. EPIC 204278916 shows much deeper dips than Tabby's Star, and they are grouped over a shorter period, whereas the dips at Tabby's Star are spread out over several years. Furthermore, EPIC 204278916 is surrounded by a proto-stellar disc, whereas Tabby's Star appears to be a normal F-type star displaying no evidence of a disc.

=== Other stars ===
An overall study of 21 other similar stars was presented in 2019.

== Light curve gallery ==

== See also ==
Disrupted planet
Tidally detached exomoon
List of stars that have unusual dimming periods
Stars named after people

== References ==

== External links ==

Where's The Flux, home page of the Tabby's Star observation project
Tabby's Star on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images