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Ongoing and Post-Mass-Transfer Binaries: A Living Catalog and Unified Review of Binary Mass Transfer Products
Lieke A. C. van Son, Natsuko Yamaguchi, Pranav Nagarajan +6
Mass transfer is arguably the most defining interaction in binary stellar systems, yet many aspects of its physics remain poorly understood, from stability to endpoints and observa…
Gaia astrometry disfavors a binary origin for long secondary periods
Cheyanne Shariat, Kareem El-Badry, Morgan MacLeod +1
Approximately one-third of luminous pulsating red giant stars exhibit long secondary periods (LSPs): stable photometric variability with periods of several months to years in addit…
The Blue Lurker WOCS 14020: A Long-Period Post-Common-Envelope Binary in M67 Originating from a Merger in a Triple System
Emily M. Leiner, Natalie M. Gosnell, Aaron M. Geller +3
We present Hubble Space Telescope far-ultraviolet (FUV) spectra of a blue-lurkerwhite-dwarf (BL-WD) binary system in the 4 Gyr open cluster M67. We fit the FUV spectrum of the W…
Radial Velocity and Astrometric Evidence for a Close Companion to Betelgeuse
Morgan MacLeod, Sarah Blunt, Robert J. De Rosa +10
We examine a century of radial velocity, visual magnitude, and astrometric observations of the nearest red supergiant, Betelgeuse, in order to reexamine the century-old assertion t…
Stellar Spin Down in Post-Mass Transfer Binary Systems
Meng Sun, Seth Gossage, Emily M. Leiner +1
Motivated by measurements of the rotation speed of accretor stars in post-mass-transfer (post-MT) systems, we investigate how magnetic braking affects the spin-down of individual s…
Wind Roche-lobe Overflow in Low-Mass Binaries: Exploring the Origin of Rapidly Rotating Blue Lurkers
Meng Sun, Sasha Levina, Seth Gossage +4
Wind Roche-Lobe Overflow (WRLOF) is a mass-transfer mechanism proposed by Mohamed and Podsiadlowski (2007) for stellar binaries wherein the wind acceleration zone of the donor star…
An Eclipsing Binary Comprising Two Active Red Stragglers of Identical Mass and Synchronized Rotation: A Post-Mass-Transfer System or Just Born That Way?
Keivan G. Stassun, Guillermo Torres, Marina Kounkel +7
We report the discovery of 2M0056-08 as an equal-mass eclipsing binary (EB), comprising two red straggler stars (RSSs) with an orbital period of 33.9 d. Both stars have masses of 1…
WIYN Open Cluster Study. LXXXVII. HST Ultraviolet Detection of Hot White Dwarf Companions to Blue Lurkers in M67
Andrew C. Nine, Robert D. Mathieu, Natalie M. Gosnell +1
We present the results of our Hubble Space Telescope far-ultraviolet survey of the blue lurkers (BLs) in M67. We find evidence for two white dwarf companions among the BLs that are…
Revealing the Field Sub-subgiant Population Using a Catalog of Active Giant Stars and Gaia EDR3
Emily M. Leiner, Aaron M. Geller, Michael A. Gully-Santiago +2
Sub-subgiant stars (SSGs) fall below the subgiant branch and/or red of the giant branch in open and globular clusters, an area of the color-magnitude diagram (CMD) not populated by…
Observationally Constraining the Starspot Properties of Magnetically Active M67 Sub-Subgiant S1063
Natalie M. Gosnell, Michael A. Gully-Santiago, Emily M. Leiner +1
Our understanding of the impact of magnetic activity on stellar evolution continues to unfold. This impact is seen in sub-subgiant stars, defined to be stars that sit below the sub…
A Census of Blue Stragglers in Gaia DR2 Open Clusters as a Test of Population Synthesis and Mass Transfer Physics
Emily M. Leiner, Aaron Geller
We use photometry and proper motions from Gaia DR2 to determine the blue straggler star (BSS) populations of 16 old (1-10 Gyr), nearby ( pc) open clusters. We find that th…
Stellar Radial Velocities in the Old Open Cluster M67 (NGC 2682). II. The Spectroscopic Binary Population
Aaron M. Geller, Robert D. Mathieu, David W. Latham +3
We present and analyse 120 spectroscopic binary and triple cluster members of the old (4 Gyr) open cluster M67 (NGC 2682). As a cornerstone of stellar astrophysics, M67 is a key cl…
WOCS 5379: Detailed Analysis of the Evolution of a Post-Mass-Transfer Blue Straggler
Meng Sun, Robert D. Mathieu, Emily M. Leiner +1
The blue-straggler binary WOCS 5379 is a member of the old (6-7 Gyr) open cluster NGC 188. WOCS 5379 comprises a blue straggler star with a white dwarf companion in a 120-day eccen…
The K2 M67 Study: Precise Mass for a Turnoff Star in the Old Open Cluster M67
Eric L. Sandquist, David W. Latham, Robert. D. Mathieu +8
We present a study of the bright detached eclipsing main sequence binary WOCS 11028 (Sanders 617) in the open cluster M67. Although the binary has only one eclipse per orbital cycl…
WIYN Open Cluster Study. LXXVII. Radial-Velocity Measurements and Spectroscopic Binary Orbits in the Open Cluster NGC 7789
Andrew C. Nine, Katelyn E. Milliman, Robert D. Mathieu +4
We introduce the stellar sample of the WIYN Open Cluster Study radial-velocity survey for the rich open cluster NGC 7789 (1.6 Gyr, [Fe/H] = +0.02). This sample lies within an 18…
Blue Lurkers: Hidden Blue Stragglers on the M67 Main Sequence Identified from their Kepler/K2 Rotation Periods
Emily Leiner, Robert D. Mathieu, Andrew Vanderburg +2
At an age of 4 Gyr, typical solar-type stars in M67 have rotation rates of 20-30 days. Using K2 Campaign 5 and 16 light curves and the spectral archive of the WIYN Open Cluster Stu…
Constraining Mass Transfer Histories of Blue Straggler Stars with COS Spectroscopy of White Dwarf Companions
Natalie M. Gosnell, Emily M. Leiner, Robert D. Mathieu +4
Recent studies show that the majority of blue straggler stars (BSSs) in old open clusters are formed through mass transfer from an evolved star onto a main-sequence companion, resu…
Observations of Spin-Down in Post-Mast-Transfer Stars and the Possibility for Blue Straggler Gyrochronology
Emily Leiner, Robert Mathieu, Natalie Gosnell +1
Blue stragglers and other mass transfer/collision products are likely born with rapid rotation rates due to angular momentum transfer during mass-transfer, merger or collisional fo…
On the Origin of Sub-Subgiant Stars II: Binary Mass Transfer, Envelope Stripping, and Magnetic Activity
Emily Leiner, Robert D. Mathieu, Aaron M. Geller
Sub-subgiant stars (SSGs) lie to the red of the main-sequence and fainter than the red giant branch in cluster color-magnitude diagrams (CMDs), a region not easily populated by sta…
On the Origin of Sub-subgiant Stars. I. Demographics
Aaron M. Geller, Emily M. Leiner, Andrea Bellini +8
Sub-subgiants are stars observed to be redder than normal main-sequence stars and fainter than normal subgiant (and giant) stars in an optical color-magnitude diagram. The red stra…
On the Origin of Sub-subgiant Stars. III. Formation Frequencies
Aaron M. Geller, Emily M. Leiner, Sourav Chatterjee +3
Sub-subgiants are a new class of stars that are optically redder than normal main-sequence stars and fainter than normal subgiant stars. Sub-subgiants, and the possibly related red…
The K2 M67 Study: An Evolved Blue Straggler in M67 from K2 Mission Asteroseismology
Emily Leiner, Robert Mathieu, Dennis Stello +1
Yellow straggler stars (YSSs) fall above the subgiant branch in optical color-magnitude diagrams, between the blue stragglers and the red giants. YSSs may represent a population of…
The K2 M67 Study: Revisiting old friends with K2 reveals oscillating red giants in the open cluster M67
D. Stello, A. Vanderburg, L. Casagrande +6
Observations of stellar clusters have had a tremendous impact in forming our understanding of stellar evolution. The open cluster M67 has a particularly important role as a calibra…
WIYN Open Cluster Study. LXXI. Spectroscopic Membership and Orbits of NGC 6791 Sub-Subgiants
Katelyn E. Milliman, Emily Leiner, Robert D. Mathieu +2
In an optical color-magnitude diagram sub-subgiants (SSGs) lie red of the main sequence and fainter than the base of the red giant branch in a region not easily populated by standa…