A. Davenport NSF Astronomy & Astrophysics Postdoctoral Fellow, Western Washington University DIRAC Fellow, University of Washington jradavenport 1 Collaborators: Kevin Covey, Riley Clarke, Zachery Laycock, Matthew Scoggins Suzanne Hawley, Brett Morris, Leslie Hebb
these giant spots appear? • How long do they live? • How often do huge flares happen? • Could they affect life? • What can spots & flares tell us about a star? • Are spots & flares on other stars the same? • How do they change over (astronomical) time? jradavenport
for GJ 1243 alone most for any star, besides the Sun! • 15% flares are “complex” higher % for large energy flares • wide energy range: Log E = 28-33 erg large solar flares around 1E32 erg jradavenport 13 Hawley et al. (2014) Davenport et al. (2014)
Mazeh, & Aigrain Figure 1. Period vs. mass with comparison to previous rotation period measurements. The 34,030 new rotation periods derived using AutoACF are shown as cyan points. The mass was derived using the models of Baraffe et al. (1998), as described in the text. This figure also displays periods from Baliunas et al. (1996) and Kiraga & Stepien (2007; 114 circles) and MEarth data from Irwin et al. (2011; 41 stars), with gray and black symbols representing objects with young and old disk kinematics, respectively, all of which have available mass estimates. Additional M-dwarf periods from the WFCAM Transit Survey (Goulding et al. 2012), for which no kinematic classification is available (65 triangles), with masses derived from Pecaut & Mamajek (2013). Also included are periods from (Hartman et al. 2011; 1686 small black dots), with mass estimates obtained using Teff and the models of Baraffe et al. (1998), and periods from (Harrison et al. 2012; 265 crosses), with masses derived from a J − K to Teff conversion using data from Kenyon & Hartmann (1995), and the isochrones of Baraffe et al. (1998). (A color version of this figure is available in the online journal.) Table 2 Details of the 99,000 Stars with No Significant Period Detection KIC Teff log g M Prot σP LPH w DC (K) (dex) (M⊙ ) (days) (days) using isochrone no. 1 for M < 0.7 M⊙ and isochrone no. 3 for higher masses, and assuming an age of ∼1 Gyr. We checked that the change in results is negligible if the age is varied by a factor of up to 10. The typical uncertainty associated with the McQuillan+2014 +30,000 Rotation Periods from Kepler Mass Prot (days) jradavenport 39
1. Surface (orange) in the three-dimensional space of color (mass, x- axis), age (Myr, y-axis), and stellar rotation period (days, z-axis). The surface is an extrapolation in age, using P ∝ √ t(Skumanich 1972), of the color–period relation observed among moderate-to-slow rotators in the Hyades and younger clusters (black curve). The black dot marks the color, age, and rotation period of the Sun. The dashed blue curves mark the ages and color ranges of the stars being observed by Kepler in the four open clusters located within its field of Figure 2. Color–magnitude g and r bands and from th http://archive.stsci.edu/kepl a 0. ◦5 radius of the cluster candidate members are ma Meibom+2011 (B-V) Age (Myr) Prot “Gyrochronology” jradavenport 40
& Aigrain e 1. Period vs. mass with comparison to previous rotation period measurements. The 34,030 new rotation periods derived using AutoACF are shown as cyan . The mass was derived using the models of Baraffe et al. (1998), as described in the text. This figure also displays periods from Baliunas et al. (1996) and a & Stepien (2007; 114 circles) and MEarth data from Irwin et al. (2011; 41 stars), with gray and black symbols representing objects with young and old disk atics, respectively, all of which have available mass estimates. Additional M-dwarf periods from the WFCAM Transit Survey (Goulding et al. 2012), for which ematic classification is available (65 triangles), with masses derived from Pecaut & Mamajek (2013). Also included are periods from (Hartman et al. 2011; 1686 black dots), with mass estimates obtained using Teff and the models of Baraffe et al. (1998), and periods from (Harrison et al. 2012; 265 crosses), with masses d from a J − K to Teff conversion using data from Kenyon & Hartmann (1995), and the isochrones of Baraffe et al. (1998). or version of this figure is available in the online journal.) Table 2 Details of the 99,000 Stars with No Significant Period Detection using isochrone no. 1 for M < 0.7 M⊙ and isochrone no. 3 for higher masses, and assuming an age of ∼1 Gyr. We checked McQuillan+2014 with +30,000 Rotation Periods? Mass Prot (days) “Gyrochronology” jradavenport 41
rotation periods derived using AutoACF are shown as cyan as described in the text. This figure also displays periods from Baliunas et al. (1996) and 2011; 41 stars), with gray and black symbols representing objects with young and old disk tional M-dwarf periods from the WFCAM Transit Survey (Goulding et al. 2012), for which from Pecaut & Mamajek (2013). Also included are periods from (Hartman et al. 2011; 1686 s of Baraffe et al. (1998), and periods from (Harrison et al. 2012; 265 crosses), with masses ann (1995), and the isochrones of Baraffe et al. (1998). l Journal Supplement Series, 211:24 (14pp), 2014 April McQuillan, Maze . mass with comparison to previous rotation period measurements. The 34,030 new rotation periods derived using AutoACF are as derived using the models of Baraffe et al. (1998), as described in the text. This figure also displays periods from Baliunas et 2007; 114 circles) and MEarth data from Irwin et al. (2011; 41 stars), with gray and black symbols representing objects with youn vely, all of which have available mass estimates. Additional M-dwarf periods from the WFCAM Transit Survey (Goulding et al. 20 fication is available (65 triangles), with masses derived from Pecaut & Mamajek (2013). Also included are periods from (Hartman et with mass estimates obtained using Teff and the models of Baraffe et al. (1998), and periods from (Harrison et al. 2012; 265 crosses K to Teff conversion using data from Kenyon & Hartmann (1995), and the isochrones of Baraffe et al. (1998). K-M dwarfs: Bimodal Period Distribution Mass 1212 A. McQuillan, S. Aigrain and T. Mazeh Figure 9. Period versus amplitude for the rotating Kepler field M dwarfs. The blue dots represent objects with Prot < 10 d, whi stable modulation patterns in their light curves, and blue stars known, short-period eclipsing binaries (Prˇ sa et al. 2011). The red do of candidate transiting planets (Batalha et al. 2013). All the other M dwarfs with detected rotation periods are shown as grey dot parameter are shown along the corresponding axis, with matching colours. Two long-period binaries are not shown as blue stars in t Figure 9. Period versus amplitude for the rotating Kepler field M dwarfs. The blue dots represent objects with Prot < 10 d, whi stable modulation patterns in their light curves, and blue stars known, short-period eclipsing binaries (Prˇ sa et al. 2011). The red do of candidate transiting planets (Batalha et al. 2013). All the other M dwarfs with detected rotation periods are shown as grey dot parameter are shown along the corresponding axis, with matching colours. Two long-period binaries are not shown as blue stars in t Figure 10. Period versus effective temperature for the rotating Kepler field Figure 11. Histogram of the short- and long-pe McQuillan+2013 McQuillan+2014 2 Possible Causes 1) New transition phase 2) Star formation history jradavenport 43
detected on HAT-P-11 with STSP (see Section 3). The radius of each circle corresponds to the size of the spot. The shading beneath corresponds to the number of times the planet occulted that spatial bin on the stellar surface, which can be used as a proxy for relative completeness. Note that the spots occur preferentially at two active latitudes near ±15 . The 6:1 period commensurability between the orbital period and stellar rotation period produces the alternating longitudinal stripes in relative occultation number. The two red circles in the western hemisphere near longitude 90 highlight the spots derived from the transit light curve in Figure 8, and the four blue circles in the eastern hemisphere near longitude 30 correspond to the spots derived from the transit light curve in Figure 6. The green circle near longitude 100 corresponds to the large spot discussed in Figure 13. for the sensitivities and biases of the di↵erent observing methods is beyond the scope of this paper. The latitude distribution of spots of HAT- show the mean latitudes of spots on each hemi- sphere of the Sun, and the standard deviations of the spot distributions. The pattern of the solar activity cycle is visible — sunspots in the 16 Figure 10. Distribution of spo years of observations for both Sun. The four years of solar spond to the maximum of sol served by Howard et al. (1984 spot latitudes and their unce from the best-fit solutions fr occultation model. Both star HAT-P-11: Active Latitudes Morris+2017 jradavenport 57
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