J/ApJ/924/L30 Impact of SpaceX Starlink satellites on ZTF obs. (Mroz+, 2022)
Impact of the SpaceX Starlink satellites on the Zwicky Transient Facility survey
observations.
Mroz P., Otarola A., Prince T.A., Dekany R., Duev D.A., Graham M.J.,
Groom S.L., Masci F.J., Medford M.S.
<Astrophys. J., 924, L30 (2022)>
=2022ApJ...924L..30M 2022ApJ...924L..30M (SIMBAD/NED BibCode)
ADC_Keywords: Surveys; Photometry, VRI; Space observations
Keywords: Artificial satellites; Astronomical site protection
Night sky brightness; Ground-based astronomy; Observational astronomy
Sky surveys
Abstract:
There is a growing concern about an impact of low-Earth-orbit (LEO)
satellite constellations on ground-based astronomical observations, in
particular, on wide-field surveys in the optical and infrared. The
Zwicky Transient Facility (ZTF), thanks to the large field of view of
its camera, provides an ideal setup to study the effects of LEO
megaconstellations-such as SpaceX's Starlink-on astronomical surveys.
Here, we analyze the archival ZTF observations collected between 2019
November and 2021 September and find 5301 satellite streaks that can
be attributed to Starlink satellites. We find that the number of
affected images is increasing with time as SpaceX deploys more
satellites. Twilight observations are particularly affected-a fraction
of streaked images taken during twilight has increased from less than
0.5% in late 2019 to 18% in 2021 August. We estimate that once the
size of the Starlink constellation reaches 10000, essentially all ZTF
images taken during twilight may be affected. However, despite the
increase in satellite streaks observed during the analyzed period, the
current science operations of ZTF are not yet strongly affected. We
also find that redesigning Starlink satellites (by installing visors
intended to block sunlight from reaching the satellite antennas to
prevent reflection) reduces their brightness by a factor of 4.6±0.1
with respect to the original design in g, r, and i bands.
Description:
The Zwicky Transient Facility (ZTF) is a new optical time-domain
survey that uses the Palomar 48 inch Schmidt-type Samuel Oschin
telescope. The survey started regular science observations on
2018-March-20. The telescope is equipped with a custom-build
wide-field camera that provides a 47deg2 field of view, one of the
largest worldwide. Thanks to the enormous field of view, ZTF can
survey the sky at a rate of ∼3760deg2 per hour to a depth of
∼20.5mag. A typical exposure time is 30s although sometimes deeper
images are taken.
In this Letter, we analyze the archival ZTF observations of Starlink
satellites collected between 2019 November and 2021 September. We find
5301 satellite streaks that can be attributed to Starlink satellites.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 109 5301 ZTF observations of Starlink satellites
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See also:
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/ApJS/249/18 : The ZTF catalog of periodic variable stars (Chen+, 2020)
J/ApJ/902/48 : ZTF early obs. of type Ia supernovae. III. (Bulla+, 2020)
J/ApJ/904/155 : gri photometry for 32 kilonovae with ZTF (Andreoni+, 2020)
J/ApJ/905/58 : Local universe with ZTF. I. Ca-rich gap transients (De+, 2020)
J/ApJ/905/145 : ZTF cand. counterparts to 13 GW follow-up (Kasliwal+, 2020)
J/ApJ/912/46 : ZTF Type II supernovae with follow-up obs. (Bruch+, 2021)
J/ApJ/912/125 : Variable white dwarfs from Gaia & ZTF phot. (Guidry+, 2021)
J/ApJ/922/33 : Periodic dwarf carbon stars from ZTF & Gaia (Roulston+, 2021)
J/AJ/162/63 : ZTF LCs of 51 stars in 12 globular clusters (Ngeow+, 2021)
J/AJ/162/94 : Cataclysmic variables in ZTF 2nd year (Szkody+, 2021)
J/AJ/163/263 : 323 YSOs properties with ZTF (Hillenbrand+, 2022)
J/AJ/164/251 : ZTF measured rot. period of 40553 M- or G-dwarfs (Lu+, 2022)
J/A+A/657/A64 : Supernovae ZTF light curves (Sollerman+, 2022)
J/A+A/675/A195 : ZTF DR11 classification in ZTF/4MOST sky (Sanchez-Saez+, 2023)
http://planet4589.org/space/con/star/stats.html : Starlink summary status
http://www.nsf.gov/news/special_reports/jasonreportconstellations/ : Impacts
of Large Satellite Constellations report
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Name Satellite name
15- 27 F13.5 d JD Julian Date of the start of the exposure
29 A1 --- Filt [gri] Filter name
31- 35 F5.2 mag mag [-0.55/10.37] Apparent magnitude in filter
37- 41 F5.2 mag e_mag [0.02/1.3] Uncertainty in mag
43- 47 F5.3 deg/s AngVel [0.139/1.31] Mean angular velocity of the
satellite
49- 56 F8.3 km Range [302.5/1752] Range
58- 63 F6.2 deg el-sun [-33/-11.8] Elevation of the Sun
65- 70 F6.2 deg az-sun [29.3/333.5] Azimuth of the Sun
72- 77 F6.2 deg al-sat [10.6/88.5] Elevation of the center of the
satellite trail
79- 84 F6.2 deg az-sat [0.8/359.3] Azimuth of the center of the
satellite trail
86- 93 F8.3 deg lam0 [-135/-104] Longitude of the subsatellite point
95- 101 F7.3 deg phi0 [24.3/42.4] Latitude of the subsatellite point
103- 109 F7.3 km alt [233.9/575.6] Altitude of the satellite
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 25-Aug-2023