Stellar Mass was clearly held in high regard early in his career because, although placed in two maidens, he made his third start in the Group 2 Beresford Stakes over a mile at the Curragh. He finished fourth that day, but was only beaten by a short-head, a neck and half a length, which was an encouraging performance. But then he was a beaten favourite in a maiden at Leopardstown a month later.
He was runner-up in another maiden on his seasonal reappearance, then finished only fourth and fifth in a pair of them over 10 furlongs, before finally opening his winning account at the eighth attempt.
That is not the sort of profile that one would expect to see on a colt who was just weeks away from making the frame in Group 1 company, but the step up to 12 furlongs has transformed him from a disappointing runner into one who is a classic-placed pattern winner whose best may still be ahead of him.
The Jim Bolger-trained Stellar Mass was bred by the partnership of Tinnakill House and Alan Byrne, and he made €280,000 in Goffs as a foal. After his maiden success he took the Magners Ulster Derby, a premier handicap, over the extended 12 furlongs at Down Royal and, just one week later, he chased home Harzand and Idaho in the Group 1 Dubai Duty Free Irish Derby at the Curragh.
He was an odds-on winner of the Listed Her Majesty's Plate Stakes over 14 furlongs at Down Royal in July, followed that with a half-length defeat of subsequent listed scorer Almela in the Group 3 Ballyroan Stakes over a mile and a half at Leopardstown, and is due to take on the classic-placed pair Bondi Beach and US Army Ranger, and the high-class filly Zhukova, in the Group 3 KPMG Enterprise Stakes over the same course and distance tomorrow.
Stellar Mass is a son of Gilltown Stud's Timeform 140-rated standout Sea The Stars (by Cape Cross) and he is one of four blacktype earners out of Juno Marlowe (by Danehill), a mare who is a full-sister to three stakes winners. Her son Fairmile (by Spectrum) is a stakes-placed prolific winner, daughter Sun of Jamaica (by Cape Cross) was Group 3-placed in Germany, and the other sibling of note is Marzelline (by Barathea).
She began her career in England, trained by Walter Swinburn, and she won a 10-furlong Lingfield maiden on her second start. She was placed a couple of times after that, but it was not until she crossed the Atlantic that she hit her peak.
There she won a listed handicap over 11 furlongs at Del Mar, was beaten by just a nose when runner-up in the Grade 2 San Gorgonio Handicap over nine furlongs on turf at Santa Anita, and then chased home Santa Tersita in the Grade 1 Santa Maria Handicap over a half-furlong less on the Pro-Ride surface. Another notable performance was her fourth place finish in the Grade 1 Yellow Ribbon Stakes over 10 furlongs, also at Santa Anita.
Juno Marlowe got her wins over seven furlongs at Kempton and Newmarket and she achieved a career-peak handicap mark of 97. Her full-brother Leporello won the Group 3 Winter Hill Stakes at Windsor and Group 3 Select Stakes at Goodwood, and full-sister Calypso Grant won the Listed Masaka Stakes at Kempton.
Poppy Carew, another full-sister, was runner-up in that mile listed contest but won the Listed John Musker Stakes at Yarmouth. She was also a runner-up in the Group 3 Prestige Stakes at Goodwood as a juvenile, and finished third in the Group 2 Sun Chariot Stakes at Newmarket.
They have a stakes-placed half-sister called Flora Trevelyan (by Cape Cross), who is quite closely related to Stellar Mass, and of the rest of their winning siblings the one-time scorer Oh Hebe (by Night Shift) deserves a mention. That is because she has produced three blacktype horses at stud, most notably the ill-fated Grade 2 Oak Tree Derby scorer Devious Boy (by Dr Devious).
Why So Silent (by Mill Reef), the unraced grandam of Stellar Mass, was out of the Group 3 Lancashire Oaks and Listed Pretty Polly Stakes winner Sing Softly (by Luthier), a filly who also performed with merit when runner-up in the Group 2 Ribblesdale Stakes and third in the Group 2 Park Hill Hill Stakes.
The best of her five successful offspring was Supreme Sound (by Superlative), who won 10 times, including the Listed Winter Derby at Lingfield and the Grade 3 Hawthorne Gold Cup, and he was runner-up in the Grade 1 United Nations Handicap at Monmouth Park.
In addition to Why So Silent, his half-sisters included Eliza Acton (by Shirley Heights) and Rosy Lydgate (by Last Tycoon). The former won once as a two-year-old and the latter was placed just once, but they are notable because of the horses who appear under them on a catalogue page. Rosy Lydgate is the grandam of Treaty Of Paris (by Haatef), who won the 2013 edition of the Group 3 Acomb Stakes.
Mile scorer Eliza Acton, on the other hand, is the dam of Stotsfold (by Barathea). He emulated his relation Leporello by taking both the Group 3 Winter Hill Stakes and Group 3 Select Stakes but then improved on that by adding the Group 3 La Coupe, Listed Gala Stakes, and Group 3 Brigadier Gerard Stakes, and he was only beaten by about one and a half lengths when third to Gio Ponti in the Grade 1 Arlington Million. Sadly, he died of colic shortly after his listed-race success.
These are the highlights of the first few generations of the pedigree, although if you go back farther you will find that the sixth dam of Stellar Mass is 1962's dual classic-placed Yorkshire Oaks heroine West Side Story (by Rockefella), who was a grand-daughter of 1944's 1000 Guineas winner Picture Play (by Donatello) and whose only start at two had been quite remarkable: she was runner-up in the Cheveley Park Stakes! Timeform rated West Side Story 127.
This means that he represents a branch of the famous Joel family from which standouts such as Royal Palace (by Ballymoss), Welsh Pageant (by Tudor Melody), Desert Prince (by Green Desert) and Make Believe (by Makfi) emerged or descended, but his connection to them is so distant as to have no relevance to his talent or potential.
It will be interesting to see how much further upwards in the rankings Stellar Mass can go, and he could be a talented stayer in 2017, perhaps even making a return visit to Irish Champions Weekend but, instead of this year's target, for the Group 1 Irish St Leger at the Curragh.