Radio Seti Observations of the Anomalous Star Kic 8462852

Harp, G. R.; Richards, J.; Shostak, Seth; Tarter, Jill; Vakoch, Douglas A.; Munson, Chris

doi:10.3847/0004-637x/825/2/155

Cited by 51 publications

(30 citation statements)

References 21 publications

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“…This yielded a sensitivity of 180 and 300 Jy Hz at 1 and 8 GHz, respectively, corresponding to a transmitter with an effective isotropic radiated power of 4 10 15 W (and 7 10 15 W) at the distance of KIC 8462852. No persistent narrowband signals were detected in the vicinity of KIC 8462852, consistent with previous results with the same instrument (Harp et al 2015).…”

Section: Simultaneous Radio Observations and Resultssupporting

confidence: 82%

“…As a test of the feasibility of simultaneously observing the same target in optical and radio regimes, the ATA reobserved KIC 8462852 at a subset of the frequencies previously reported (Harp et al 2015) on three of the six nights during which optical observations were conducted. The ATA's fully automated system for spectral analysis searched for narrowband emissions between 0.01 and 10 Hz wide, with real-time followup of any candidate signals (Tarter et al 2011).…”

Section: Simultaneous Radio Observations and Resultsmentioning

confidence: 99%

“…While the power requirement for a detectable, isotropic narrowband radio transmission from KIC 8462852 is obviously quite high (Harp et al 2015), even modest targeting on the part of the putative extraterrestrials can reduce these numbers substantially. If we assume that the extraterrestrials are using an antenna the same size as the Arecibo radio telescope in Puerto Rico, the minimum detectable transmitter power (again, for narrowband signals) is only about 200 megawatts for frequencies near 1 GHz, and 4 megawatts for frequencies close to 10 GHz.…”

Section: Discussionmentioning

confidence: 99%

“…In the current study we ask whether a civilization capable of such a large-scale engineering project might also be transmitting intentional electromagnetic signals. An earlier search for extraterrestrial intelligence (SETI) using the Allen Telescope Array (ATA) in northern California was conducted for narrowband and broadband radio signals between 1 GHz and 10 GHz (Harp et al 2015). No signals were detected.…”

Section: Introductionmentioning

confidence: 99%

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Optical Seti Observations of the Anomalous Star Kic 8462852

Schuetz¹,

Vakoch²,

Shostak

et al. 2016

ApJL

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To explore the hypothesis that KIC 8462852's aperiodic dimming is caused by artificial megastructures in orbit (Wright et al. 2015), rather than a natural cause such as cometary fragments in a highly elliptical orbit (Marengo et al. 2015), we searched for electromagnetic signals from KIC 8462852 indicative of extraterrestrial intelligence. The primary observations were in the visible optical regime using the Boquete Optical SETI Observatory in Panama. In addition, as a preparatory exercise for the possible future detection of a candidate signal (Heidmann 1991), three of six observing runs simultaneously searched radio frequencies at the Allen Telescope Array in California. No periodic optical signals greater than 67 photons/m 2 within a time frame of 25 ns were seen. This limit corresponds to isotropic optical pulses of 8 10 22 joules. If, however, any inhabitants of KIC 8462852 were targeting our solar system (Shostak & Villard 2004), the required energy would be reduced greatly. The limits on narrowband radio signals were 180 -300 Jy Hz at 1 and 8 GHz, respectively, corresponding to a transmitter with an effective isotropic radiated power of 4 10 15 W (and 7 10 15 W) at the distance of KIC 8462852. While these powers requirements are high, even modest targeting could -just as for optical signals -lower these numbers substantially.

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Section: Simultaneous Radio Observations and Resultssupporting

confidence: 82%

Section: Simultaneous Radio Observations and Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Optical Seti Observations of the Anomalous Star Kic 8462852

Schuetz¹,

Vakoch²,

Shostak

et al. 2016

ApJL

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“…These were subsequent to the observations in 2015 (Harp et al 2016). From 2017 July 8 through August 8, 1022 separate 92 s observations were performed that resulted in scanning 1419-4303 MHz for radio signals.…”

Section: Radio Setimentioning

confidence: 99%

The First Post-Kepler Brightness Dips of KIC 8462852

Boyajian

Alonso

Ammerman

et al. 2018

ApJL

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We present a photometric detection of the first brightness dips of the unique variable star KIC 8462852 since the end of the Kepler space mission in 2013 May. Our regular photometric surveillance started in 2015 October, and a sequence of dipping began in 2017 May continuing on through the end of 2017, when the star was no longer visible from Earth. We distinguish four main 1%-2.5% dips, named "Elsie," "Celeste," "Skara Brae," and "Angkor," which persist on timescales from several days to weeks. Our main results so far are as follows: (i) there are no apparent changes of the stellar spectrum or polarization during the dips and (ii) the multiband photometry of the dips shows differential reddening favoring non-gray extinction. Therefore, our data are inconsistent with dip models that invoke optically thick material, but rather they are in-line with predictions for an occulter consisting primarily of ordinary dust, where much of the material must be optically thin with a size scale =1 μm, and may also be consistent with models invoking variations intrinsic to the stellar photosphere. Notably, our data do not place constraints on the color of the longer-term "secular" dimming, which may be caused by independent processes, or probe different regimes of a single process.

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Radio SETI observations of the interstellar object ′OUMUAMUA

et al. 2019

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Motivated by the hypothesis that 'Oumuamua could conceivably be an interstellar probe, we used the Allen Telescope Array to search for radio transmissions that would indicate a non-natural origin for this object. Observations were made at radio frequencies between 1-10 GHz using the Array's correlator receiver with a channel bandwidth of 100 kHz. In frequency regions not corrupted by man-made interference, we find no signal flux with frequency-dependent lower limits of 0.01 Jy at 1 GHz and 0.1 Jy at 7 GHz. For a putative isotropic transmitter on the object, these limits correspond to transmitter powers of 30 mW 10 W and 300 mW 100 W, respectively. In frequency ranges that are heavily utilized for satellite communications, our sensitivity to weak signals is badly impinged, but we can still place an upper limit of 10 W 3 kW for a transmitter on the asteroid. For comparison and validation should a transmitter be discovered, contemporaneous measurements were made on the solar system asteroids 2017 UZ and 2017 WC with comparable sensitivities. Because they are closer to Earth, we place upper limits on transmitter power to be 0.1 and 0.001 times the limits for 'Oumuamua, respectively.

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Radio Seti Observations of the Anomalous Star Kic 8462852

Cited by 51 publications

References 21 publications

Optical Seti Observations of the Anomalous Star Kic 8462852

Optical Seti Observations of the Anomalous Star Kic 8462852

The First Post-Kepler Brightness Dips of KIC 8462852

Radio SETI observations of the interstellar object ′OUMUAMUA

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