Celestial hemisphere:  Northern  ·  Constellation: Taurus (Tau)
usnoa2-1125-01255816 , 


            Morten Balling
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Acquisition details

Basic astrometry details

Astrometry.net job: 372795

RA center: 03h46m02s.4

DEC center: +24°1142

Pixel scale: 0.963 arcsec/pixel

Orientation: -176.263 degrees

Field radius: 0.088 degrees

Resolution: 588x368

File size: 244.5 KB


Edits/updates at the end of the despription!

Normally when I've captured a series of light frames, I blink through them after they have been registered (aligned), to look for anything moving. A few times I've seen asteroids and minor planets.

This one is a little different. The moving object is a star! It has a boring name (usnoa2-1125-01255816) and that's about the only information I've been able to find.

It is found at 03h45m50s +24deg11'41", in the middle of M45. The characteristic blue and red stars close by should lead you the way.

It's apparent magnitude is somewhere between 18 and 19, but I can't find that anywhere, so it's based on a visual estimate comparing it with known stars (using skymap.org). In the CI image, which has better colour fidelity, the star looks orange or red.

The images are from DSS taken by the Palomar 48-inch Schmidt telescope, and my Crowd Image of M45. The DSS image was taken between Nov. 5, 1986 and Sept. 11, 1996. The images used in the Crowd Image was taken primarily the last couple of years.

The motion is somewhere around 6" in 27 years, based on the green channel of the DSS image, which was shot first (1986) and the CI image shot in2013 (estimated average). That's quite a lot, but nothing compared to Barnard's Star, which moves 10" pr year. On the other hand: Barnard's Star is a mag 9.5 red dwarf, so it's a lot closer to earth than usnoa2-1125-01255816 at mag 18-19. Therefore the movement of usnoa2-1125-01255816 is quite significant, and maybe even larger than Barnard's Star.

EDIT: I've tried to do a simple calculation of the motion of usnoa2-1125-01255816. Assuming that it is a red dwarf similar to Barnard's Star, a rule of thumb is to add 5 to apparent magnitude for every 10 times increase of distance. Barnard's Star (am9) is 6 ly away, so that put's usnoa2-1125-01255816 at 100 times that distance or 600 ly. If usnoa2-1125-01255816 isn't a red dwarf it put's it even further away. That means that the motion of usnoa2-1125-01255816 should also be multiplied by at least 100 (or more), to be comparable to Barnard's Star. Therefore the motion of usnoa2-1125-01255816 at the same distance as Barnard's Star is perhaps up to 22" pr. year. That is twice that of Barnard's Star! Might be have a new known record here?

2nd EDIT: The star is already known to have high proper motion, according to Simbad.


3rd EDIT: This is actually pretty interesting. First: From hereon I'll use the name NLTT11761 instead. It's "easier" The star has a Bmag of 19,7 and a Rmag of 15.6 (red and blue mag), indicating that it is indeed red. An average of the two magnitudes is about 17.5. That means that the star is more than 10 times further away than Barnard's Star giving it a very large proper motion. On the other hand it could be a lot closer. High proper motion is normally an indicator of nearby stars (if a star is close the movement in arc sec pr year will appear larger, than if it's further away).

4th EDIT: My calculations are still very loose, but I'm beginning to belive that NLTT11761 is a so called Hyper Velosity Star, based on estimates of it's space velocity. The star is a type K-M spectral class, making it (probably) an orange dwarf. Lot's of ifs here, but it's pretty interesting to study. I'm learning a lot, that might come in handy

Image credit

A. Tag, Abel de Burgos, achrntatrps, Adam Evans, Ahmad, Alex Gorstan, Alex Lovell-Troy, Alexey Kljatov, Álvaro Pérez Alonso, Alvinillo, Andrea Pistocchini, Andy Rogers, Angel Requena, Anttler, äquinoktium, arcturus13, Armelle & Eric, Asaf Braverman, AstroGG, Ben Gilsrud, benedicte, beta_kappa, Bob Familiar, Bob Star, Boris Stromar, Brett Schaerer, Bryant Olsen, cafuego, Cameraguy34, Carl Drinkwater, Carsten Frenzl, chong huang, Chun-yi Li, Claustonberry, Cobbler, Cody Garges, Cristóbal Alvarado Minic, Dan Seagrave, Dan Watt, Danny Flippo, Darren, David DeHetre, Davide De Col, Dennis Harper, Did23, Donky_Tramp, Eduardo Mariño, eifionglyn, EmileLeTueur, Eric Gorski, Eric Kilby, Evaldas Granickas, Fermion, Ferran Ginebrosa, Filip Lolić, Flavastro, Florian Meyer, Forrest Tanaka, Forrest Tanaka, Francisco Soto, Francisco Soto, Franck Schneider, Frank Carey, Franz Haar, Fred Locklear, Fredrik Ödling, galaad16, geco71, Gianluca, gianni, gianni, Giuliano Pinazzi, hjghjfgjfg, IZAYOI YUKARI, James Hartshorn, Jason Hullinger, Javier Falcón Quintana, Jean-Daniel Pauget, Jill Robidoux, Jim Keller, Jim Mac, john.purvis, johnny9s, Jorge, Jose Carlos Castro, jpstanley, Juan Jimenez, Juan Lozano, Kristian Urdal, LLacertae, Luca Argalia, Luis Argerich, Lukáš Kalista, m1fcj, Marc Van Norden, Mario Bertsch, Mark Philpott, MarkC1952, Matthew Cheng, Matthias, maxgaspa, Mike Durkin, Mike Markiw, Mike Miller, Miodrag Sekulic, Miquel, Morten Balling, nd-nʎ, neptun, Nick Ares, Nick Bramhall, Olivier x, Paul_Blakeman, PaulHutchinson, pbkwee, Peleg Wasserman, Pete Collins, Peter Gottstein, Phil Hosey, Phillip Seeber, poppet with a camera, Preis Alois, [email protected], Ralph W, Ram Viswanathan, Richie Jarvis, RIKY, Ro Irving, Rob Glover, Roberto Ferrero, Rochus Hess, s58y, Salvatore Iovene, Salvopa, Serge, Sergei Golyshev, Shin-ichi Ueda, Stan McQueen, Stefano Morandi, Stelios ZACHARIAS, Stéphane Bourgault, Stephen Hanafin, Stephen Little, Stephen Rahn, Steve, Steve Yan, stevebryson, Steven Duckworth, sweeper, taitan, Tarfin T, theilr, Thomas Bresson, Tim, Tino Leichsenring, Tomofwight, Upupa4me, vastateparksstaff, Vedran Vrhovac, vetenskapsman, Wayne Young, Yodatheoak, Yohan Riou & Yusuke Morimoto.

NASA, ESA and AURA/Caltech


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Sky plot