J/AJ/170/264 NETS. III. Activity & RV from NEID of 41 systems (Gupta+, 2025)
The NEID Earth Twin Survey.
III. Survey performance after three years on sky.
Gupta A.F., Fitzmaurice E., Mahadevan S., Robertson P., Luhn J.K.,
Wright J.T., Logsdon S.E., Krolikowski D.M., Paredes L.A., Bender C.F.,
Giovinazzi M.R., Lin A.S.J., Blake C.H., Canas C.I., Ford E.B.,
Halverson S., Kanodia S., McElwain M.W., Monson A., Ninan J.P.,
Rajagopal J., Roy A., Schwab C., Stefansson G., Terrien R.C.
<Astron. J., 170, 264 (2025)>
=2025AJ....170..264G 2025AJ....170..264G
ADC_Keywords: Exoplanets; Radial velocities; Stars, activity; Spectra, optical;
Infrared; Stars, double and multiple
Keywords: Exoplanet astronomy ; Exoplanet detection methods ; Radial velocity ;
Surveys
Abstract:
The NEID Earth Twin Survey (NETS) has been delivering a rich set of
precise radial velocity (RV) measurements for 41 bright, nearby
main-sequence stars. Here, we describe the status of the survey after
3yr on sky, and we present the full set of RV measurements and
accompanying stellar activity indicators. We discuss intermediate
survey diagnostics, including calibration of the known RV zero-point
offset introduced following the Contreras fire in 2022 and the
identification of an undiagnosed and previously unknown zero-point
offset in 2021. An analysis of our data set using RVSearch
demonstrates that for these target stars, NEID is independently
sensitive to nearly all known planets with periods shorter than the
NETS observing baseline. We also highlight a number of newly detected
RV signals, which present exciting opportunities for future
investigations.
Description:
The NN-EXPLORE Exoplanet Investigations with Doppler Spectroscopy
(NEID) Earth Twin Survey (NETS) is a dedicated search for low-mass,
long-period exoplanets with NEID, an extreme precision radial velocity
(EPRV) spectrograph (optical to near-infrared; 380-930nm) on the WIYN
3.5m telescope at Kitt Peak National Observatory in Arizona, USA.
We retrieved the processed spectra from the NEID data archive. Nine of
the 41 stars in our sample are known to host planetary systems. Data
collected during Science Run 1 (2020 October 26-2022 June 16) and
Science Run 2 (2022 October 18-2024 August 19) are treated as distinct
RV eras. We have also identified an apparent RV zero-point offset in
the middle of Science Run 1, so we consider data taken from 2020
October 26-2021 August 31 as a separate "Run 0.5."
NETS observations formally commenced in 2021 September. Data
collection proceeded smoothly through the 2021B semester but was
interrupted twice during the 2022A semester. The first interruption
resulted from a failure of the etalon calibration source in early 2022
May. The second interruption began in 2022 June when NEID was shut
down. The instrument was restarted in 2022 October, NEID returned to
on-sky operations on November 11, and NETS observations recommenced on
November 30. the WIYN primary mirror support system failed in 2023
September, taking the telescope offline for 2weeks. Observations
resumed at the end of the month, and there were no further
interruptions through the end of the 2024A semester.
The total number of nights of high-quality observations for each NETS
target is given in Table 1. While some stars reached the intended rate
of 36 visits per year, many others did not. This shortfall is a
consequence of multiple factors including weather losses, which are
most pronounced in February and July, as well as the aforementioned
facility interruptions.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 99 41 NEID Earth Twin Survey observing statistics
fig2.dat 120 5920 NEID activity indicator time series measurements
fig8.dat 50 5920 NEID radial velocity time series
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See also:
III/159A : Ca II H and K Measurements Made at MWO (Duncan+ 1991)
J/A+A/410/1051 : ELODIE surv. for north. extra-solar planets. II. (Naef+, 2003)
J/ApJ/708/1366 : RVs for 61 Vir (Vogt+, 2010)
J/ApJ/830/46 : RVs of 3 Neptune-mass planet hosts (Fulton+, 2016)
J/AJ/154/200 : The nearby white dwarf/red dwarf pair 40 Eri BC (Mason+, 2017)
J/AJ/155/126 : RVs & photometry of the K dwarf HD26965 (Diaz+, 2018)
J/AJ/155/203 : HARPS-N RVs & activity ind. for Kepler-1655 (Haywood+, 2018)
J/A+A/625/A17 : SOPHIE data of Gliese 411 (Diaz+, 2019)
J/A+A/646/A77 : Chromospheric activity from AMBRE-HARPS (Gomes da Silva+, 2021)
J/AJ/161/130 : List of 100 targets for NEID Earth Twin Survey (Gupta+, 2021)
J/AJ/161/134 : Survey of stellar & planetary comp. within 25pc (Hirsch+, 2021)
J/ApJS/255/8 : The California Legacy Surv. I. Planet cat. (Rosenthal+, 2021)
J/AJ/163/183 : S-value for 59 Sun-like starswith HIRES and HKP (Baum+, 2022)
J/AJ/163/218 : Radial velocity of Gliese 411 with APF and HIRES (Hurt+, 2022)
J/AJ/163/171 : The EXPRES Stellar Signals Project. II. RVel (Zhao+, 2022)
J/AJ/166/46 : EXPRES. IV. Two Additional Planets Orbiting (Brewer+, 2023)
J/A+A/678/A2 : YARARA V2. 4 high proper motion stars RVs (Cretignier+, 2023)
J/A+A/674/A39 : Gaia DR3. 95 extrasolar planets (Gaia Coll.+, 2023)
J/AJ/166/123 : EXPRES radial volocity for τ Ceti (Korolik+, 2023)
J/AJ/165/176 : Doppler constr. companions to Sun-like stars (Laliotis+, 2023)
J/ApJS/274/35 : The California Legacy Surv. V. Activ. cycles (Isaacson+, 2024)
J/AJ/170/52 : NETS. II. RV & astrometry of 7 star systems (Giovinazzi+, 2025)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Star Star name
12- 15 I4 --- tau [861/1270] Total NEID baseline
17- 18 I2 --- Nobs0.5 [1/25]? Number of observations during Run 0.5
20- 21 I2 --- Nobs1 [9/49] Number of observations during Run 1
23- 25 I3 --- Nobs2 [28/115] Number of observations during Run 2
27- 30 F4.2 --- RVrms0.5 [0.62/3.4]? Radial velocity rms during Run
0.5 (1)
32- 35 F4.2 --- RVrms1 [0.73/4.66] Radial velocity rms during Run 1
(1)
37- 40 F4.2 --- RVrms2 [0.6/4.54] Radial velocity rms during Run 2
(1)
42- 46 F5.2 --- ZP0.5-1 [-1.38/3.71]? Zero-point offset during RV era
Run 0.5-Run 1 (2)
48- 52 F5.2 --- ZP1-2 [-0.33/5.22]? Zero-point offset during RV era
Run 1-Run 2 (2)
54- 61 A8 --- Fig2 NEID activity indicator time series
measurements and GLS periodograms
(Figure 2 in JPG format)
63- 70 A8 --- Fig8 Results for the RVSearch run with no trend
for all stars with no known signals from
long-period companions
(Figure 8 in JPG format)
72- 79 A8 --- Fig9 Results for the blind RVSearch run for all
stars with known signals from long-period
companions (Figure 9 in JPG format)
81- 89 A9 --- Fig10 Results for the informed RVSearch run for all
stars with known signals from long-period
companions (Figure 10 in JPG format)
91- 99 A9 --- Fig11 Results for the RVSearch run with a trend
test for all stars with no known signals from
long-period companions
(Figure 11 in JPG format)
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Note (1): rms values are not reported for stars with fewer than three visits in
a given run.
Note (2): Zero-point offsets are not reported for stars with known RV signals
induced by long-period stellar or planetary companions.
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Byte-by-byte Description of file: fig2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Star Star identifier
12- 24 F13.5 d BJD [2459220/2460510] Barycentric Julian date
(mid-point) of observation
26- 32 F7.5 --- SHK [0.11/0.7]? Mount Wilson S-index, scaled
34- 40 F7.5 --- e_SHK [1.2e-4/0.022]? Uncertainty in SHK
42- 48 F7.5 --- CaIIHK [0.095/0.59] Telluric corrected, Ca II H&K
(S-index) (1)
50- 56 F7.5 --- e_CaIIHK [1e-4/0.04] Uncertainty in CaIIHK
58- 64 F7.5 --- Ha06-1 [0.19/0.73] Telluric corrected, Hα, 0.6
Angstrom window index (1)
66- 72 F7.5 --- e_Ha06-1 [1.1e-4/9.8e-4] Uncertainty in Ha06-1
74- 80 F7.5 --- NaI [0.06/0.45] Telluric corrected, Na I NIR
Doublet index (1)
82- 88 E7.5 --- e_NaI [8e-05/4.3e-4] Uncertainty in NaI
90- 96 F7.5 --- CaIRT [0.32/0.47] Telluric corrected, Ca II NIR
triplet at 8498.018A (1)
98- 104 F7.5 --- e_CaIRT [1.6e-4/7.1e-4] Uncertainty in CaIRT
106- 112 F7.5 --- Mn539 [0.53/0.88] Telluric corrected, Mn I (539.4nm)
index (1)
114- 120 F7.5 --- e_Mn539 [3.8e-4/2e-3] Uncertainty in Mn539
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Note (1): As defined in the NEID Pipeline algorithms, Version 1.4.1:
http://neid.ipac.caltech.edu/docs/NEID-DRP/algorithms.html#stellar-activity-info
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Byte-by-byte Description of file: fig8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- Star Star identifier
12- 24 F13.5 d BJD [2459220/2460510] Barycentric Julian date
(mid-point) of observation
26- 35 F10.5 km/s RVel [-100.3/84.8] Radial velocity
37- 43 F7.5 km/s e_RVel [1.9e-4/2.2e-3] Uncertainty in RVel1
45- 50 A6 --- Run NEID Run number (1)
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Note (1): Run as follows:
RUN0.5 = "Run 0.5" (2020 October 26-2021 August 31); We identified an
apparent RV zero-point offset in the middle of Science Run 1 so
we consider this data as a separate "Run 0.5."; 327 occurrences
RUN1 = Science Run 1 (2020 October 26-2022 June 16); 1800 occurrences
RUN2 = Science Run 2 (2022 October 18-2024 August 19); 3793 occurrences
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History:
From electronic version of the journal
License: CC-BY-4.0
References:
Gupta et al. Pap I 2025AJ....169....1G 2025AJ....169....1G
Giovinazzi et al. Pap II 2025AJ....170...52G 2025AJ....170...52G J/AJ/170/52
Gupta et al. Pap III 2025AJ....170..264G 2025AJ....170..264G This catalog
Giovinazzi et al. Pap IV 2026AJ....171..286G 2026AJ....171..286G J/AJ/171/286
(End) Robin Leichtnam [CDS] 24-Jul-2026