Editing Triangulum Galaxy (section)

=== Location – distance – motion ===
[[File:Andromeda constellation map (1).png|thumb|upright=1.45|Triangulum (M33; lower left of center) and Andromeda Galaxy ([[Andromeda Galaxy|M31]]; above center)]]
Estimates of the distance from the Milky Way to the Triangulum Galaxy range from {{Convert|2380|to|3070|e3ly|kpc|abbr=on|lk=on}} (or 2.38 to 3.07&nbsp;[[Mly]]), with most estimates since the year 2000 lying in the middle portion of this range,<ref name=aass06/><ref name=apj696/> making it slightly more distant than the Andromeda Galaxy ([[Andromeda Galaxy#Distance estimate|at 2,540,000 light-years]]). At least three techniques have been used to measure distances to M 33. Using the [[Cepheid variable]] method, an estimate of {{Convert|2770|+/-|130|e3ly|kpc|abbr=on}} was achieved in 2004.<ref name=aj127/><ref name=ap49/> In the same year, the [[tip of the red-giant branch]] (TRGB) method was used to derive a distance estimate of {{Convert|2590|+/-|80|e3ly|kpc|abbr=on}}.<ref name=mnras350/> The Triangulum Galaxy is around 750,000 light years from the Andromeda Galaxy.<ref>{{cite web |url=http://www.messier.seds.org/m/m033.html |title=Messier 33 |access-date=22 July 2024 |website=SEDS Messier Catalog}}</ref>

In 2006, a group of astronomers announced the discovery of an [[eclipsing binary|eclipsing binary star]] in the Triangulum Galaxy. By studying the eclipses of the stars, astronomers were able to measure their sizes. Knowing the sizes and temperatures of the stars, they were able to measure the [[absolute magnitude|absolute]] magnitude of the stars. When the [[Apparent magnitude|visual]] and absolute magnitudes are known, the distance to the star can be measured. The stars lie at the distance of {{Convert|3070|+/-|240|e3ly|kpc|abbr=on}}.<ref name=aass06/>  The average of 102 distance estimates published since 1987 gives a [[distance modulus]] of 24.69, or .883 [[Megaparsec|Mpc]] (2,878,000 light-years).<ref>{{Cite web | url=http://ned.ipac.caltech.edu/cgi-bin/objsearch?objname=messier+33&extend=no&hconst=73&omegam=0.27&omegav=0.73&corr_z=1&out_csys=Equatorial&out_equinox=J2000.0&obj_sort=RA+or+Longitude&of=pre_text&zv_breaker=30000.0&list_limit=5&img_stamp=YES | title=Your NED Search Results}}</ref>

The Triangulum Galaxy is a source of [[Astrophysical maser|H<sub>2</sub>O maser]] emission.<ref name=apj708/> In 2005, using observations of two water masers on opposite sides of Triangulum via the [[Very Long Baseline Array|VLBA]], researchers were for the first time able to estimate the angular rotation and [[proper motion]] of Triangulum. A velocity of {{nowrap|190 ± 60&nbsp;km/s}} relative to the Milky Way was computed, which means Triangulum is moving towards [[Andromeda Galaxy]] and suggesting it may be a satellite of the larger galaxy (depending on their relative distances and margins of error).<ref name=science307_5714/> 

In 2004, evidence was announced of a clumpy stream of hydrogen gas linking the Andromeda Galaxy with Triangulum, suggesting that the two may have tidally interacted in the past. This discovery was confirmed in 2011.<ref name=nra020120613/>  A distance of less than 300 kiloparsecs between the two supports this hypothesis.<ref name="pawlowski">{{Cite journal |last1=Pawlowski |first1=Marcel S. |last2=Kroupa |first2=Pavel |last3=Jerjen |first3=Helmut |date=November 2013 |title=Dwarf galaxy planes: the discovery of symmetric structures in the Local Group |journal=[[Monthly Notices of the Royal Astronomical Society]] |volume=435 |issue=3 |pages=1928–1957 |arxiv=1307.6210 |bibcode=2013MNRAS.435.1928P |doi=10.1093/mnras/stt1384 |issn=1365-2966 |s2cid=53991672 |doi-access=free}}</ref>

The [[Pisces Dwarf]] (LGS 3), one of the small Local Group member galaxies, is located {{Convert|2022|e3ly|kpc|abbr=on}} from the Sun. It is 20° from the [[Andromeda Galaxy]] and 11° from Triangulum. As LGS 3 lies at a distance of {{Convert|913|e3ly|kpc|abbr=on}} from both galaxies, it could be a [[satellite galaxy]] of either Andromeda or Triangulum. LGS 3 has a core radius of {{Convert|483|ly|pc|abbr=on}} and {{nowrap|2.6 × 10<sup>7</sup>}} solar masses.<ref name=apj562_2/>

Pisces VII/Triangulum (Tri) III may be another satellite of Triangulum.<ref>{{Cite web |last=Lazaro |first=Enrico de |date=18 November 2021 |title=Amateur Astronomer Discovers New Dwarf Galaxy |url=https://www.sci.news/astronomy/pisces-vii-dwarf-galaxy-10283.html |website=Sci.News |language=en-US}}</ref>