J/A+A/691/A117 2MASS J15594729+4403595 light curves and spectra (Messina+, 2024)
The curious case of 2MASS J15594729+4403595, an ultra-fast M2 dwarfs
with possible Rieger cycles.
Messina S., Catanzaro G., Lanza A.F., Gandolfi D., Serrano M.M., Deeg H.J.,
Garcia-Alvarez D.
<Astron. Astrophys. 691, A117 (2024)>
=2024A&A...691A.117M 2024A&A...691A.117M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, dwarfs ; Stars, M-type ; Photometry ; Optical ;
Spectra, optical ; Spectra, infrared
Keywords: stars: activity - stars: late-type -
stars: individual: 2MASS J15594729+4403595 - stars: rotation -
starspots - open clusters and associations: general
Abstract:
RACE-OC (Rotation and ACtivity Evolution in Open Clusters) is a
project aimed at characterizing the rotational and magnetic activity
properties of the late-type members of open clusters, stellar
associations, and moving groups of different ages. The evolution in
time of rotation and activity at different masses shed light on the
evolution of the stellar internal structure, on magneto-hydro-dynamic
processes operating in the stellar interior, and on the
coupling/decoupling mechanisms between radiative core and external
convective envelope. As part of this project, in the present paper we
present the results of an investigation of a likely member of the AB
Doradus association, the M-type star 2MASS J15594729+4403595.
In the present study we aimed to reveal the real nature of our target,
which turned out to be a hierarchical triple system, to derive the
stellar rotation period and surface differential rotation, and to
characterize its photospheric magnetic activity.
We have collected RV and photometric time series, complemented with
archive data, to determine the orbital parameters and the rotation
period and have used the spot modeling technique to explore what
causes its photometric variability.
We found 2MASS J15594729+4403595 to be a hierarchical triple system
consisting of a dwarf SB1 M2 and a companion M8. The M2 star has a
rotation period P=0.37d, making it the fastest among M-type members of
AB Dor. The most relevant result is the detection of a periodic
variation of the spotted area on opposite stellar hemispheres which
resembles a sort of Rossby waves or Rieger-like cycles on an extremely
short time scale. Another interesting result is the occurrence of a
highly significant photometric periodicity P=0.443d, which may be
related to the stellar rotation either in terms of a Rossby wave or of
surface differential rotation.
2MASS J15594729+4403595 may be the proto-type of a new class of
extremely fast rotating stars exibiting short Rieger-like cycles. We
will further explore what may drive these short-duration cycles as
well as will search for other similar stars to allow a statistical
analysis.
Description:
2MASS J15594729+4403595 V- and R-band differential photometry
collected at the Zeta Uma Observatory and reduced spectra.
Objects:
-------------------------------------------------------------------
RA (2000) DE Designation(s)
-------------------------------------------------------------------
15 59 47.30 +44 03 59.7 2MASS J15594729+4403595 = TIC 417545885
-------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
vband.dat 34 184 V-band differential photometry
rband.dat 46 10 R-band differential photometry
list.dat 186 13 List of fits spectra
fits/* . 13 Individual fits spectra
--------------------------------------------------------------------------------
Byte-by-byte Description of file: vband.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.4 d HJD Heliocentric Julian Day
18- 23 F6.4 mag deltaVmag Differential V magnitude
29- 34 F6.4 mag e_deltaVmag Standard deviation on V magnitude
--------------------------------------------------------------------------------
Byte-by-byte Description of file: rband.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.4 d HJD Heliocentric Julian Day
17- 23 F7.4 mag deltaRmag Differential R magnitude
29- 34 F6.4 mag e_deltaRmag Standard deviation of R magnitude
36- 40 F5.3 mag delta(V-R) Differential V-R colour index
42- 46 F5.3 mag e_delta(V-R) Standard deviation of differential V-R colour
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 13 F7.4 s RAs Right ascension (J2000)
14 A1 --- DE- Declination sign (J2000)
15- 16 I2 deg DEd Declination (J2000)
18- 19 I2 arcmin DEm Declination (J2000)
21- 27 F7.4 arcsec DEs Declination (J2000)
29- 34 I6 --- Nx Number of pixels along X-axis
36- 56 A21 "datime" Obs.date Observation date
58- 64 F7.2 0.1nm blambda Lower value of wavelength value
66- 73 F8.2 0.1nm Blambda Upper value of wavelength value
75- 83 F9.7 0.1nm dlambda Wavelength resolution
85- 87 I3 Kibyte size Size of FITS file
89-132 A44 --- FileName Name of FITS file, in subdirectory fits
134-186 A53 --- Title Title of the FITS file
--------------------------------------------------------------------------------
Acknowledgements:
Sergio Messina, sergio.messina(at)inaf.it
(End) Patricia Vannier [CDS] 11-Sep-2024