Discovery of two distinct red clumps in NGC 419: a rare snapshot of a cluster at the onset of degeneracy

Colour-magnitude diagrams (CMDs) of the Small Magellanic Cloud (SMC) star cluster NGC 419, derived from Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) data, reveal a well-delineated secondary clump located below the classical compact red clump typical of intermediate-age populations. We demonstrate that this feature belongs to the cluster itself, rather than to the underlying SMC field. Then, we use synthetic CMDs to show that it corresponds very well to the secondary clump predicted to appear as a result of He-ignition in stars just massive enough to avoid e(-)-degeneracy settling in their H-exhausted cores. The main red clump instead is made of the slightly less massive stars which passed through e(-) degeneracy and ignited He at the tip of the red giant branch. In other words, NGC 419 is the rare snapshot of a cluster while undergoing the fast transition from classical to degenerate H-exhausted cores. At this particular moment of a cluster`s life, the colour distance between the main-sequence turn-off and the red clump(s) depends sensitively on the amount of convective core overshooting, Lambda(c). By coupling measurements of this colour separation with fits to the red clump morphology, we are able to estimate simultaneously the cluster mean age (1.35(-0.04)(+0.11) Gyr) and overshooting efficiency (Lambda(c) = 0.47(-0.04)(+0.14)). Therefore, clusters like NGC 419 may constitute important marks in the age scale of intermediate-age populations. After eye inspection of other CMDs derived from HST/ACS data, we suggest that the same secondary clump may also be present in the Large Magellanic Cloud clusters NGC 1751, 1783, 1806, 1846, 1852 and 1917.

A view of Sir Isaac Newton's philosophy

by Dr. Pemberton

Letters from Benjamin Welles to John Henry Tudor, 1799-1801

Benjamin Welles wrote these six letters to his friend and classmate, John Henry Tudor, between 1799 and 1801. Four of the letters are dated, and the dates of the other two can be deduced from their contents. Welles wrote Tudor four times in September 1799, at the onset of their senior year at Harvard, in an attempt to clear up hurt feelings and false rumors that he believed had caused a chill in their friendship. The cause of the rift is never fully explained, though Welles alludes to "a viper" and "villainous hypocrite" who apparently spread rumors and fueled discord between the two friends. In one letter, Welles asserts that "College is a rascal's Elysium - or the feeling man's hell." In another he writes: "College, Tudor, is a furnace to the phlegmatic, & a Greenland to thee feeling man; it has an atmosphere which breathes contagion to the soul [...] Villains fatten here. College is the embryo of hell." Whatever their discord, the wounds were apparently eventually healed; in a letter written June 26, 1800, Welles writes to ask Tudor about his impending speech at Commencement exercises. In an October 29, 1801 letter, Welles writes to Tudor in Philadelphia (where he appears to have traveled in attempts to recover his failing health) and expresses strong wishes for his friend's recovery and return to Boston. This letter also contains news of their classmate Washington Allston's meeting with painters Henry Fuseli and Benjamin West.

Andover (including North Andover), Massachusetts, 1852 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Map of the town of Andover, Essex County, Massachusetts, surveyed by authority of the town by Henry F. Walling, civil engineer. It was published by Lithy. of A. Kollner in 1852. Scale 1:18,000. Covers the towns of Andover and North Andover, Massachusetts. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Massachusetts State Plane Coordinate System, Mainland Zone (in Feet) (Fipszone 2001). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows features such as roads, railroads, drainage, public buildings, schools, churches, cemeteries, industry locations (e.g. mills, factories, mines, etc.), private buildings with names of property owners, town, school district and parish boundaries, and more. Relief is shown by hachures. This layer is part of a selection of digitally scanned and georeferenced historic maps of Massachusetts from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates (1755-1922), scales, and purposes. The digitized selection includes maps of: the state, Massachusetts counties, town surveys, coastal features, real property, parks, cemeteries, railroads, roads, public works projects, etc.

Concord, Massachusetts, 1852 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Map of the town of Concord, Middlesex County, Mass., [by] H.F. Walling, civil engr. It was published in 1852. Scale [ca. 1:18,400]. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Massachusetts State Plane Coordinate System, Mainland Zone (in Feet) (Fipszone 2001). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows features such as roads, railroads, drainage, public buildings, schools, churches, cemeteries, industry locations (e.g. mills, factories, mines, etc.), private buildings with names of property owners, town and town district boundaries and more. Relief is shown by hachures. Includes view: Monument at the "Old North Bridge," and inset: Concord Village. With note that White Pond and Walden Pond are described from surveys made by Henry David Thoreau. This layer is part of a selection of digitally scanned and georeferenced historic maps of Massachusetts from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of regions, originators, ground condition dates (1755-1922), scales, and purposes. The digitized selection includes maps of: the state, Massachusetts counties, town surveys, coastal features, real property, parks, cemeteries, railroads, roads, public works projects, etc.

Pamphlets - homoeopathic.

Title from spine.

Sir Thomas Elyots̓ The defence of good women,

"The defence of good women was first published in 1540. The only known copy of this edition is in the Henry E. Huntington library; this copy is here reproduced in a line-for-line and letter-for-letter reprint."--Introd., p. viii.

Russell on the power and duty of an arbitrator and the law of submissions and awards : and references under order of court, with an appendix of forms, precedents, and statutes.

Mode of access: Internet.

A remembravnce, of the woorthie and well imployed life, of the Right Honorable Sir Nicholas Bacon knight ... who deceased, the 20 daye of Februarie 1578. UUith an exhortation necessarie for euery estate.

"Reproduced from the copy in the Henry E. Huntington Library."

A remembraunce of the precious vertues of the right Honourable and reuerend Iudge, Sir Iames Dier ... who disseased at great Stawghton, in Huntingdonshire, the 24. of Marche, Anno. 1582.

"Reproduced from the copy in the Henry E. Huntington Library."

Autobiography and political correspondence of Augustus Henry,

Mode of access: Internet.

Engravings from the works of Sir Joshua Reynolds, P.R.A. /

Mounted mezzotint engravings after portraits by Sir Joshua Reynolds, executed mainly by Samuel William Reynolds and by numerous other engravers: Richard Parkes Bonington, W.A. Rainger, Frederik Bromley, George H. Every, James Scott, George Sanders, A. Sanders, Joseph W. Edwards, John Richardson Jackson, R. José, H.C. Balding, Charles Tomkins, George Salisbury Shury, Richard Josey, Charles Algernon Tomkins, Arthur Turrell, William Henry Egleton, A.N. Sanders, William T. Hulland, T. Hunt, Stephen H. Gimber, H. Davis, Edwin Hunt, Thomas Lewis Atkinson, T. José, A. Scott.

The gospels in art; the life of Christ by great painters from Fra Angelico to Holman Hunt, the text by Léonce Bénédite, Henry Van Dyke, R. F. Horton and the Bishop of Derry & Raphoe;

On cover : The Bible in art: The New Testament.

Shakespeare's King Henry V.

Mode of access: Internet.