J/AJ/163/183 S-value for 59 Sun-like starswith HIRES and HKP (Baum+, 2022)
Five Decades of Chromospheric Activity in 59 Sun-like Stars and New Maunder
Minimum Candidate HD 166620.
Baum A.C., Wright J.T., Luhn J.K., Isaacson H.
<Astron. J., 163, 183 (2022)>
=2022AJ....163..183B 2022AJ....163..183B
ADC_Keywords: Stars, G-type; Photometry; Optical; Stars, ages; Stars, masses;
Effective temperatures
Keywords: Stellar activity ; Maunder minimum ; Stellar chromospheres ;
Magnetic fields ; Solar cycle
Abstract:
We present five decades of chromospheric activity measurements in 59
Sun-like stars as time series. These include and extend the 35yr of
stellar chromospheric activity observations by the Mount Wilson Survey
(1966-2001), and continued observations at Keck by the California
Planet Search (1996-). The Mount Wilson Survey was studied closely in
1995, and revealed periodic activity cycles similar to the Sun's 11yr
cycle. The California Planet Search provides more than five decades of
measurements, significantly improving our understanding of these
stars' activity behavior. We have curated the activity measurements in
order to create contiguous time series, and have classified the
stellar sample according to a predetermined system. We have analyzed
29 stars with periodic cycles using the Lomb-Scargle periodogram, and
present best-fit sinusoids to their activity time series. We report
the best-fit periods for each cycling star, along with stellar
parameters (Teff, log(g), vsin(i), etc.) for the entire sample. As a
first application of these data, we offer a possible Maunder minimum
candidate, HD166620.
Description:
The Mount Wilson program was started in 1966 and has since become one
of the most extensive records of stellar chromospheric activity. From
1966 to 1977, the project utilized the "HKP-1" photometer: a
photoelectric scanner on the coude focus of the 100inch telescope.
Measurements continued in 1977 on the "HKP-2" photometer: a new
photomultiplier on the Cassegrain focus of the 60inch telescope. We
collected the data for all stars observed between 1966 and 1995 from
Radick & Pevtsov, 2018 DOI:10.7910/DVN/ZRJ6NT and
DOI:10.7910/DVN/H85QPF. We take HIRES-1 data from 1996 to 2004 from
Wright+, 2004AJ....128.1273W 2004AJ....128.1273W.
Brewer+, 2016, J/ApJS/225/32 provides a source for precise stellar
parameters for F, G, and K stars that were unavailable to Baliunas+,
1995ApJ...438..269B 1995ApJ...438..269B.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 47 62135 Curated S-values
table2.dat 91 59 *Parameters and classifications of program stars
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Note on table2.dat: The final two columns compare the classifications
from Baliunas+, 1995ApJ...438..269B 1995ApJ...438..269B (B95), if included in their
sample, and the classifications from this work. Following a similar
format as B95, our classifications for cycling stars provide the
estimated period. All stars for which a periodogram analysis was not
sufficient due to variable periodicity or significant gaps in data
collection (see Section 3.1), include a "?" following their period
estimate. These estimates were made by eye.
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See also:
B/simbad : Simbad objects catalogue (M.Wenger 2000)
III/159 : Ca II H and K Measurements Made at MWO (Duncan+ 1991)
J/ApJS/152/261 : Chromospheric Ca II emission in nearby stars (Wright+, 2004)
J/AJ/138/312 : Activity of bright solar analogs (Hall+, 2009)
J/ApJ/725/875 : Chromospheric activity for CPS stars (Isaacson+, 2010)
J/ApJS/225/32 : Extended abundance analysis of cool stars (Brewer+, 2016)
J/ApJ/835/25 : Calibrated solar S-index time series (Egeland+, 2017)
J/AJ/159/235 : Radial Velocity jitters in 600 planet host stars (Luhn+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- HD Stellar identifier
9- 14 F6.4 --- Svalue [0.1/0.88] S-value
16- 28 F13.8 yr Time [1966/2021] Fractional year of observation
30- 36 A7 --- Inst Instrument used; HIRES or HKP
38- 47 A10 --- Flag Data flag (1)
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Note (1): Flags as follows:
none = no data flag (58880 occurrences)
1day = precision is only within one day (2782 occurrences)
sigma = rejected point due to sigma-clipping (444 occurrences)
1day/sigma = one day precision and sigma-clipped (29 occurrences)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- HD Stellar identifier
9- 13 F5.3 --- Svalue [0.13/0.46] Median S-value, excludes
sigma-clipped values
15- 18 I4 K Teff [4937/6002] Effective temperature (1)
20- 23 F4.2 [cm/s2] logg [3.46/4.61] log surface gravity (1)
25- 29 F5.3 km/s vsini [0.1/9.6] Projected rotation velocity (1)
31- 37 F7.4 [Sun] Fe/H [-0.73/0.35] log Metallicity (1)
39- 43 F5.3 Msun Mass [0.69/6.37] Mass (1)
45- 48 F4.1 Gyr Age [1.3/14.7] Age (1)
50- 57 A8 --- SpType SIMBAD spectral type
59- 60 I2 yr Base [24/54] Baseline (2)
62- 66 F5.2 --- Cadence [1.77/86.6] Average number of observations /year
68- 85 A18 --- ClassB95 Baliunas+ 1995ApJ...438..269B 1995ApJ...438..269B classification (3)
87- 91 A5 --- ClassTP This paper's classification (4)
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Note (1): Values from Brewer+, 2016, J/ApJS/225/32B (B16). Uncertainties:
Teff±25K;
logg±0.028;
vsini±0.7km/s;
Fe/H±0.010.
Mass and age were modelled using these spectroscopic parameters.
See B16 for additional details.
Note (2): Number of years star was observed from first to final observation:
calculated in this paper.
Note (3): For the purposes of our work, we have included the FAP grade in the
classifications from 1995. The error in period estimate was not
included, but for the stars given a secondary classification, this
is noted after the plus sign, ie. HD100180 had a primary
classification of period 3.6years and fair FAP grade, and a
secondary classification of a 12.9year period, also given a
fair FAP grade.
Note (4): All periods listed are rough estimates, and are estimated only to
the precision of one tenth of a year. This follows the same format
as B95 period estimates
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 03-May-2022