J/AJ/165/61 12 transiting Kepler exoplanet properties (Sheikh+, 2023)
A Green Bank Telescope Search for Narrowband Technosignatures between 1.1 and
1.9GHz During 12 Kepler Planetary Transits.
Sheikh S.Z., Kanodia S., Lubar E., Bowman W.P., Canas C.I., Gilbertson C.,
MacDonald M.G., Wright J., MacMahon D., Croft S., Price D., Siemion A.,
Drew J., Worden S.P., Trenholm E., Graduate SETI Course at Penn State,
The Breakthrough Listen Initiative
<Astron. J., 165, 61 (2023)>
=2023AJ....165...61S 2023AJ....165...61S
ADC_Keywords: Exoplanets; Spectra, radio
Keywords: Technosignatures ; Search for extraterrestrial intelligence ;
Astrobiology ; Biosignatures ; Radio astronomy ; Exoplanets ;
Transits
Abstract:
Agrowing avenue for determining the prevalence of life beyond Earth is
to search for "technosignatures" from extraterrestrial
intelligences/agents. Technosignatures require significant energy to
be visible across interstellar space and thus intentional signals
might be concentrated in frequency, in time, or in space, to be found
in mutually obvious places. Therefore, it could be advantageous to
search for technosignatures in parts of parameter space that are
mutually derivable to an observer on Earth and a distant transmitter.
In this work, we used the L-band (1.1-1.9GHz) receiver on the Robert
C. Byrd Green Bank Telescope to perform the first technosignature
search presynchronized with exoplanet transits, covering 12 Kepler
systems. We used the Breakthrough Listen turboSETI pipeline to flag
narrowband hits (∼3Hz) using a maximum drift rate of ±614.4Hz/s
and a signal-to-noise threshold of 5-the pipeline returned ∼3.4x105
apparently-localized features. Visual inspection by a team of citizen
scientists ruled out 99.6% of them. Further analysis found two signals
of interest that warrant follow up, but no technosignatures. If the
signals of interest are not redetected in future work, it will imply
that the 12 targets in the search are not producing transit-aligned
signals from 1.1 to 1.9GHz with transmitter powers >60 times that of
the former Arecibo radar. This search debuts a range of innovative
technosignature techniques: citizen science vetting of potential
signals of interest, a sensitivity-aware search out to extremely high
drift rates, a more flexible method of analyzing on-off cadences, and
an extremely low signal-to-noise threshold.
Description:
In this work, we describe the first radio technosignature search that
preplanned observations to synchronize with exoplanets during their
transits, in a survey of a dozen exoplanets in the Kepler field. Using
6hr of L-band (1.1-1.9GHz) data taken with the Breakthrough Listen
(BL) bankend on the Green Bank Telescope (GBT), we performed a SETI
search using the narrowband signal search code turboSETI.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 84 12 Stellar and planetary properties for the twelve
transiting Kepler planets observed in this work
--------------------------------------------------------------------------------
See also:
J/ApJ/767/94 : 1.1-1.9GHz SETI survey of KOIs. I. (Siemion+, 2013)
J/AJ/152/181 : SETI observations of exoplanets with the ATA (Harp+, 2016)
J/ApJ/822/86 : False positive probabilities Q1-Q17 DR24 KOIs (Morton+, 2016)
J/ApJ/869/66 : Search for extraterrestrial intelligence with ATA (Harp+, 2018)
J/AJ/161/55 : Observation of 31 G-stars at 1.5GHz with GBT (Margot+, 2021)
J/A+A/658/A10 : 3C295 LOFAR, MERLIN and VLA images (Bonnassieux+, 2022)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Planet Planet
14- 15 I2 h RAh [18/19] Hour of Right Ascension (J2000)
17- 18 I2 min RAm Minute of Right Ascension (J2000)
20- 24 F5.2 s RAs Second of Right Ascension (J2000)
26 A1 --- DE- [+] Sign of declination (J2000)
28- 29 I2 deg DEd [38/51] Degree of Declination (J2000)
31- 32 I2 arcmin DEm Arcminute of Declination (J2000)
34- 38 F5.2 arcsec DEs Arcsecond of Declination (J2000)
40- 42 I3 pc Dist [120/992] Distance (1)
44- 48 F5.2 Rgeo Rad [0.79/12.2] Radius, Earth units (1)
50- 54 F5.2 Rgeo E_Rad [0.04/2] Upper uncertainty in Rad (1)
56- 60 F5.2 Rgeo e_Rad [-0.8/-0.04] Lower uncertainty in Rad (1)
62- 66 F5.2 d Per [0.89/24.6] Orbital period, days (1)
68- 74 F7.2 d BJD [964/1007] T0; BJD-2450000 (1)
76- 79 I4 K Teq [510/2080] Equivalent temperature (1)
81- 84 I4 K Teff [3464/5703] Effective temperature (1)
--------------------------------------------------------------------------------
Note (1): We use from Morton+, 2016, J/ApJ/822/86 for all planets,
except Kepler-446b which we pull from Muirhead+, 2015ApJ...801...18M 2015ApJ...801...18M.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 30-May-2023